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Keith Miller
11-11-2007, 10:35 PM
I just completed GM TBI install on a Jeep 258 straight 6 stock motor. I running stock everything except a glasspack muffler. I have also installed a Motorcraft TFI coil on the stock distributor (weights and vacuum advance removed) with large rotor and distributor cap , 8.8 mm wires and am using a GM 8 pin EST. I have checked all voltages and run the Initial System Setup/Must Read checks. Timing is set a 0 with unplugged bypass, IAC is set a 500 rpm, TPS is .46 which is a little low, and fuel pressure is 12 lbs input, 1-2 lbs return. Fuel pump is an E2182 and ECM is 1227747. Donor vehicle was a Chevy Astro Van 4.3 Liter. On to the problem. The first few times I started the motor is started well and ran great. Now the motor will not start. The initial fuel sprayed into the Throttle Body during the Starter run seems to be flooding the motor. The only way I have found to get the motor started is to let the motor flood on the initial attempt to start, unplug the injectors and crank until the motor catches and then quickly connect the injectors again.

Does anyone have any ideas as to how to correct this problem?

Does the GM ECM have a flood circuit where flooring the accelerator will cut out the fuel flow to pass the overflow of fuel? It does seem to work in my application.

During a couple of test drives, the horsepower seems a little weak with the current setting. I haven't built an ALDL cable yet, and will need to borrow a laptop for logging data. I need to get the starting issue fixed before trying any fine tuning.

Bill noted in one of the threads that the GM tables are heavy on fuel at startup for an AMC motor, but I wouldn't think it was so bad that it would flood the engine.

Bill USN-1
11-11-2007, 11:13 PM
The ECM does have a clear flood mode.
If the throttle is held above about 65% during cranking it will reduce the fuel while cranking.
Have you connected pin A and B of the aldl to get the error codes?

Have you rechecked the fuel pressure?
You may want disconnect the return line and run it into a bucket to see if it makes a difference.

You said it worked fine when you first started it and now it doesn't.

Did you change anything? Try to remove the chip, change wiring?

Have you performed the key on and engine run voltage checks?
It could be as simple as the temp sensor connection.

Keith Miller
11-12-2007, 10:11 PM
I tried checking voltages again. Coolant temp was 3.75 Volts when the engine was cold, and 1.56V when the engine was all the way warm and idling at 700 rpm after about 14 minutes. TPS was .43 volts from B to A. Map was 4.73 from B to A. O2 sensor was .38 when engine was warm but not running. I performed the fuel return line to a bucket suggestion and noted significant fuel flow (I wasn't expecting this). I installed a pressure meter on the return fuel line and it is still reading about 2 lbs. Of note, with the pressure meter in the loop the motor did start regularily on two attempts. The return fuel line is 3/8 out of the Throttle Body, and is reduced to 1/4 hardline where I installed the meter near the charcoal canister. I seems that the motor coughs one time during attempts to start and if it catches, all is good. If it doesn't, I have to pull the plug on the injectors. The 65% WOT flood clear doesn't seem to work in my case, although I do have full travel using the gas pedal.

The only ALDL code I'm getting is a 12.

The only changes I made prior to this problem starting were to retard the timing to get to 0 degrees with bypass disconnected, and to cleanup the wiring and install it in split loom. I can't rule out missing a wire somewhere during cleanup, but it doesn't seem to be in the sensors and the motor runs well once it is started.

Bill USN-1
11-12-2007, 10:34 PM
Was the map reading with the eng running? 4.75 is basically 100 map.

You may want to do the complete key on and eng running voltage checks as listed on sheet 1.

Keith Miller
11-13-2007, 09:03 PM
Bill,

This is probably too much information, but just to show that I really am performing the checks you suggest


Key On Cold Running 700 RPM

12.48 V for 2 Sec. 14.0V A1
--- --- A2
--- --- A3
113 mV 200mV A4 Not Connected
85 mv 14.3V A5
12.51 V 14.2V A6
128 mV 300mV A7 Not Connected
3-4.5 V 3-5 V A8
4.99 V 4.98 V A9
5 mV 11.3 V A10 Not Connected
11 mV 11 mV A11
8 mV 8 mV A12

12.5 V 14.2 V B1
12.4 for 2 Sec. 14.18 V B2
.4 mV 2 mV B3
--- --- B4
21 mV 2 V B5
--- --- B6
4.99 V 4.98 V B7
13 mV 13 mV B8 Not Connected
--- --- B9
3mV 14 V B10
--- --- B11
--- --- B12

--- --- C1
--- --- C2 No wire in Harness
11.26 V .8 13 V switching C3
2 mV .8 13 V switching C4
11.29 V .8 13 V switching C5
5 mV .8 13 V switching C6
11 V 14 V C7
--- --- C8
0 V .1 mV C9
3.72 V 1.44 V C10
4.7 V 1.24 V C11
--- --- C12
.448 V .463 V C13
4.99 V 4.98 V C14
--- --- C15
12.5 V 14.2 V C16

.77 mV .82 mV D1
10.1 mV 10 mV D2
--- --- D3
60 mV 1.2 V D4
76 mV 4.73 V D5
.8 mV 1 mV D6
.39 V .5 V D7
--- --- D8
--- --- D9
--- --- D10
--- --- D11
--- --- D12
--- --- D13
12.5 V 14.1 V D14
--- --- D15
12.5 V 14.1 V D16

All voltages were checked at the ECM. The voltages look pretty good to me but you're the expert. Note: I was able to get ECM flood clearing to work by starting with the accelerator pedal up when engaging the starter and then go to WOT. The flood cleared and the motor started. Not an ideal way to start the motor but at least it does work without pulling the injector wires.

Bill USN-1
11-14-2007, 10:23 PM
There's never too much information.

Couple thoughts....
1. The voltage difference on D1 and D2 concerns me. It's not much but considering that they are soldered together just inside the ECM makes me think there is a bad ground somewhere.
2. I am assuming that with the 4.98 on B7 that you have it tied to C14.

3. Where are you getting your voltage from? Where is your 12V for B1 and C16 tied to and how are you powering A6/
You should check your voltage drop on these during cranking.

4. Is C9 connected? If it is, are you getting 12V during cranking on this pin?

5. Where is your map sensor mounted?
It should be above the vacuum port it is connected to on the back of the TBI. Make sure th hose is not holding fuel in it.

Keith Miller
11-18-2007, 09:55 PM
It's been a couple of days since I was able to troubleshoot the TBI. To answer your questions.

1. I checks all the connections again and to only difference is that the wiring diagram I am using shows A11 tied to D2. All these are signal grounds, and the stock harness didn't have this connection. I went ahead and made the connection. I'm still getting .86mV at D1 and 11 mV at D2. Since the ground is being supplied by the ECM, and not the sensors, I don't know where the difference might be coming from. I still need to check my crimps at the engine ground, but I believe I made all the ground connections to the same point on the block.

2. Yes B7 is connected to C14

3. Voltage for B1 and C16 is connected straight to the Battery lead after the 15A fuse. A6 is powered from the relay, except that A6 and 8 pin module + are spliced and going to one contact on the relay via a single wire.

Voltage is down to about 9 volts during cranking, the battery is getting weak from continuous cranking trying to get it started and to clear the flooding.

4. C9 is connected to the starter solenoid and again is about 9 Volts during cranking.

5. Map sensor is mounted above the vacuum port and the hose has no fuel in it.

This problem is worst when the engine is hot. Most times I am able to crank the cold engine and get it started. I looks like the injectors are dumping way too much fuel during the initial cranking. Once started cold, or after clearing the flood the engine runs really well with no codes being generated, other than the VSS which isn't there.

I should have data logging capability shortly after Thanksgiving. Will a data log do any good for the hot flooding problem?

Bill USN-1
11-18-2007, 11:22 PM
At the end of the wiring FAQ you will see where I talk about the grounds.
D1 and D2 are soldered together inside the ECM just like A11 and A12.
The D1 A11 connection is external in the harness for the sensor grounds.

There is also a table in the program that will add fuel if the voltage is low.
I would think this was added to assist with winter starts when the engine turns slow and the voltage is low.
I normally zero these out when I set up a chip.
Have you completely charged the battery and tried it?

But some logged data may help.
The BLM's along with the data log during nrmal running and then when turned off and restarted.

Keith Miller
12-11-2007, 10:47 PM
Bill,

It's been a while since I have asked for any more assistance. I have the Jeep starting pretty reliability while cold, although it still floods badly when warm. I have been trying to log data, but after about 3 minutes of logging, the data stops (20) no longer pulses green. I added an LED to the cable prior to the Transitor in my logging cable to see if the data stream is being interupted, and it does not appear to be stopping, so I think the problem may be in the data actually going into WIN ALDL. I have to unplug the USB cable and shut down and restart ALDL to get data going again, and then it just stops again. I'm trying to troubleshoot other causes of the flooding and got to thinking that I had to replace one fuel injector from the orginal pair with another junk yard replacement. I have been trying to cross reference the fuel injector part numbers to determine if they are compatible with each other. One injector (from the original TBI) is GM 5235203RDP 2202 GM* and the replacement is GM 5235203 RPD 9070 GM. Could either one of these be from a V8? I have noted that the Rich Flag is toggling during times when I am monitoring WINALDL.

Thanks,

Bill USN-1
12-11-2007, 11:20 PM
the 5203 is the 4.3 injectors.

The rich flag cycling during closed loop is normal since the ECM has to swing the fuel from rich to lean so it can always stay in the middle.

Make sure there is nothing else running on the laptop and that there are no power savers/sleep enabled.

Keith Miller
12-16-2007, 11:10 PM
Bill,

I was finally able to generate a .BLM file with over 30 minutes of running time. I have sent this file along with several .Log files that hopefully capture my troubles during warm cranking. These files have been sent to your email address.

Thanks for the assistance,

Bill USN-1
12-16-2007, 11:50 PM
well definately have some issues.

First I would recommend doing the initial setup procedures in the FAQ's.
The TPS is too low.
Next the IAC is maxing out at 85 counts.
I'll have to look at your bin but all the bins I have dealt with are set at 145.
You may have IAC problems.
Have you verified it is working? There are a couple recent threads discussing this.

Next you are always in clear flood mode.
This makes me think you have a wiring issue concerning the crank sense wire C9 iirc.

All of these will cause starting problems.

lhc_cj7
12-17-2007, 08:32 PM
Bill, can you post his log and bin. I'm intersted in seeing this. Thanks

Keith Miller
01-03-2008, 11:17 PM
Bill,

I have reset the TPS and other initial setup procedures and now the TPS appears to be more in line with the expected values. IAC is indicating 140+ when the engine if first starting up but seems to settle into max 85 after warm up. I have swapped the IAC with another junkyard unit and the reading seem to be about the same. The Clear Flood flag seems to be intermintent, or may have to do with initial start up. It will often be set at initial start up and continue to be set for the duration of the drive, but it is often not present after a second startup. I have found that the engine will start up from cold, or after only several seconds of being turned off. Anything after a minute or two and I have the flood condition. The wiring looks like it is going directly to C9 and no where else, but I still need to ring it out just to make sure. I will be emailing you another log and BLM file. The drive was primarly highway for about 25 minutes. I know you would rather see a more all around sample of driving conditions and will try to get another BLM file soon. I was hoping you could give the log file another look and see if I'm getting closer to the baseline values

Keith Miller
02-04-2008, 09:45 PM
I have discovered on more piece to the flooding problem. After driving the Jeep for the last couple of months expecting that I will have to remove the fuel injector wires from the TBI when warm starting the engine, I finally have figured out that if I floor the gas pedal before cranking the engine, and keeping the pedal down during cranking, the engine with catch. If I floor the gas after cranking has started the damage is already done and I have to remove the injector wires to clear the flood. Once started the engine runs pretty well and I'm not showing any error codes except the VSS which is not installed. The VSS error will usually occur sometime in the next 15 minutes while decelerating.

Bill USN-1
02-04-2008, 10:31 PM
Got your email.
Sorry you got lost in all my shuffle before.
I have been doing 12hr days for a while now.

Have you tried to remove the crank sensor wire?
IIRC it's C9.

lexum
03-09-2008, 07:34 PM
Wow, I finally found an active thread about the exact same problem I am having. I want to follow along here and try and add more data to help solve this TBI flooding issue.

Some brief information about my setup:
88 YJ 258, Howell TBI, TFI coil, Duraspark module(until now) - with resistor wire in place.

Reasons for touching the working system on my Heep:
I am only getting about 15 mpg. I took some WinALDL data and found that all of my BLMs were in the 112 to 118 range. The idle kept dropping low, probably because of the rich condition.

I came across the same flooding problem this week while I tried to upgrade my ignition module to HEI. I couldn't get it working until I realized that the resistor wire needs to be bypassed. The TFI coil is pretty much useless with this resistor wire in place. Also, I read that the Howell TBI does not work properly with anything less than 12 volts from the coil?

The engine runs wonderfully once it is started. However, it barely starts cold (fires at about 500 rpms and creeps up very slowly to a 1200 rpm cold start idle) and floods immediately on a hot start.

I read about the "clear flood mode" in the manual, but it only worked part of the time. I now realize after reading this thread that you have to have the ECM powered before you floor it. Thanks for the info!

What can I do to help? Should I get the same BLM data and compare? Why would the TBI start perfect every time with the original setup (Duraspark and resistor wire) and then flood with the HEI ignition module (I am assuming that Keith removed the resistor wire when he did the TFI coil)?

I read somewhere that the Duraspark ignition module advances the timing during a hot start and the HEI module does not. Does this have anything to do with this issue?

Bill USN-1
03-10-2008, 11:50 PM
Howell FI normally is a fuel only system and you use your stock ignition.
Choice is yours what model..duraspark or HEI.

IIRC Kieth used a complete system with timing control so his problem should not be related to yours unless something really wierd happened.

Now even with full efi you can chose what coil to run..but that does not mean the complete ignition system or module.

The GM E-core and the ford TFI coils are both popular choices.

So I recommend you start with the basics like a complete voltage check and then the fuel pressure on the inlet and return lines.
Then try to log some data to see how the sensors are operating.

lexum
03-11-2008, 05:09 PM
This is exactly what I am getting at!

Has Keith solved his problem yet? I suspect it has nothing to do with his FI setup. We are having the same symptom regardless of whether our system controls spark or not.

I have checked my fuel pressure and tried running with the return fuel in a gas container. There is no difference. Fuel pressure is not my issue.

While I was out checking my fuel pressure I ran the following tests with a spark gap of .045", duraspark, distributor upgrade with 8mm wires:

1. Starting with HEI ignition module, bypassed resistor wire = fires once or twice and then dies, flooded

2. Starting with HEI ignition module, with resistor wire = fires once or twice and then dies, flooded

3. Starting with Duraspark ignition module, bypassed resistor wire = starts with low rpm and creeps up about 1200 rpm

4. Starting with Duraspark ignition module, with resistor wire = immediately starts and jumps above 1200 rpm

Once running, I do not have any issues other than a rough idle with the Duraspark setup. Is there reason to believe that I should run the Duraspark IM with resistor wire and spark gap to .035". Like I said before, I think the TFI coil is useless if it is only powered with 9V.

As soon as I get access to my wife's laptop I will log data for all of these setups to see which of these setups is running closest to stoich. Remember, my reason for going HEI is to try and correct the rich condition. If HEI works then I can setup the 8-pin module, add spark to my chip, and run Full EFI like you guys!

Thanks for the quick response Bill.

lexum
03-12-2008, 07:50 PM
After toying with the HEI and spark gap and timing and fuel pressure and injectors and clear flood mode... I have given up on the HEI ign mod for now. I tried 2 different HEI ign mods and the engine floods before they can fire up. I no longer believe that the HEI module will improve my mpg anyway.

I returned to the Duraspark with resistor wire and the system start beautifully.

So back to the rich running Howell TBI. There seems to be too much fuel all the time not just while starting. Last week, I did some datalogging with the Duraspark. The data showed that I was running in the 110 BLMs, rich.

I wish there was a way to post the txt file from WinALDL...

Bill USN-1
03-12-2008, 08:52 PM
Almost sounds like the distr wires are reversed when using the HEI.

You need to perform the initial setup procedures.
The IAC goes to 0 at idle and yes you are rich all the time.
Next time you log...uncheck the raw box and also save the BLM table when done.

And if you are a supporting member you can add attachments.

Eric VanBuren
03-13-2008, 12:04 AM
I agree with Bill that it is highly possible that the pickup wires were reversed with the HEI module.

I am confused as to your set up though, the stock 88 Jeep DuraSpark has a fixed dist with computer controlled timing. While it uses the old school Ford pickup coil and horseshoe connector coil it uses a unique Jeep spec module with Weatherpack connectors. The pick up connects to the EEC-III which computes the timing and signals the module to fire the coil. How is this interfaced with the TBI? Or did you substute a early mech/vac advance distributor and blue grommet module with the Ford style connectors?

On Ford applications of the horseshoe coil there is no resistor in the coil (+) feed. The resistor serves to limit the current through the coil and thus the coil driver to protect it. If you have swapped in the mechnical dist and corresponding module then you can remove the resistor and swap in the TFI coil. The higher output coil will not improve the idle quality however, the voltage requirement is at its lowest during idle.

lexum
03-13-2008, 05:40 AM
The stock 88 YJ comes with the Carter BBD and the emissions computer. Yes, the ignition module was routed through the computer to control the distributor. The Howell TBI is fuel only control, no spark. The "nutter bypass" is performed routing the ignition module directly to the distributor.

I had tried switching the distributor lines coming from the HEI ign mod. I could not get it to run long enough to change the timing. I got to the point where my vacuum advance was hitting my block and I could not go any further.

The data log I sent you, Bill, was with the Duraspark that has been running and starting fine, just running rich and stumbling a bit at idle. I am not sure why the IAC is going to 0. Where is the IAC, might I have plugged it? I think I have run the setup procedure many times. Are you referring to jumping A and B on ALDL connector and disconnecting the stepper motor and setting idle?

If it is just a plugged IAC I am going to cry...

lexum
03-13-2008, 07:13 AM
I think I understand what you are saying.

My data shows that my IAC is set too low(open).

If my IAC is wide open the data will show 0 but the computer will try to compensate with a rich mixture and try to maintain a 750 rpm idle.

So, I think the way to correct this is to slowly close the IAC, let the computer adjust the mixture (not sure how long I need to wait), check the IAC data, and repeat until the IAC data reads 750 rpm.

Is this correct?

The Howell TBI has always run like this, even with the preset IAC from the factory. It says in my manual that the IAC adjustment should not need adjusting (as in the setup procedure should not be attempted) and they put a seal over the adjustment screw to discourage the end user from changing it. Perhaps I just got one that was not adjusted properly.

Anyway, I will give this a try tonight if you can confirm that I am on the right track. Thanks, again!

Bill USN-1
03-13-2008, 07:48 AM
You can'tdjust the IAC itself. You can adjust the amount of air going in by adjusting the throttle plate via the min idle screw. Then as the idle speed is reached the ECM will position the IAC to maintain the proper idle. The ECM is driving it to 0 trying to get the idle lower and can't.
I doubt the IAC is plugged but a simple finger over the hole above will tell you if it's moving.
I doubt the ECM will adjust the fuel enough to compensate for how rich you are.
Either the chip will need tuned or you need to lower the fuel pressure.
But you need to measure it first to know what it is and if it is really high, why.
I don't like to run them lower then 11psi so if your at 13 you can lower it, provided the pressure is steady.


When you ran the HEI was it mounted on a flat, grounded, heat sink?

rick W.
03-13-2008, 10:23 AM
My data shows that my IAC is set too low(open).

If my IAC is wide open the data will show 0 but the computer will try to compensate with a rich mixture and try to maintain a 750 rpm idle.


IAC at 0 means the computer has commanded it to go fully closed and not let air go past if it's working correctly.
You have the scenario right though only the air is going past the throttle blades and the computer is trying to compensate....

lexum
03-13-2008, 10:28 AM
Yeah, after posting I realized from some research that the IAC value of 0 means it is trying to close. And it is closing because it is trying to bring the idle down but cannot because there is so much fuel coming out of the injectors. I am idling around 600 to 700 rpm. The idle is not rocketing up or running too high.

I don't think the Howell TBI fuel pressure regulator is adjustable without removing parts from the TBI unit. The round part of the regulator is on the bottom of the unit, while most TBI units have it up top with an adjustment. My fuel pressure gauge only reads up to 10 psi, so I only know that it is higher than 10 on the inlet. The fuel return line is about 1 psi. I imagine you would recommend putting some kind of flow restrictive device between the pump and the TBI unit in an attempt to reduce fuel flow to the TBI unit. This is what the fuel regulator should be doing anyway. I do have the tools to retune the chip(most of it came from my Honda tuning kit). It is just my understanding that the presets from Howell should fit better than this.

The HEI was setup just like the Stealth HEI mod. I sacrificed an extra Duraspark case, mounted the module flat against the inside of the case with computer CPU heat sink grease. I did this with two modules and had the same results. The module was grounded to the case and wire harness(black wire) and I assume the case is grounded to the Jeep when it is mounted on the fender.

rick W.
03-13-2008, 10:47 AM
Doesn't the Howell system use a standard GM throttle body? These can be made to be adjustable but you really need to get a gage that works withing the right perameters.....I assume you have a suitable pump?

lexum
03-13-2008, 10:50 AM
Pump came with the Howell kit, should be 12-15 psi. Supposedly, the regulator on the TBI unit is preset to 12 psi from Howell.

Here is what I am working on:

http://www.4x4xplor.com/images/TBI/DSC07952.jpg

And this is what you are probably accustomed to:

http://users.california.com/~eagle/figs/howell/tbi.gif

rick W.
03-13-2008, 10:54 AM
The one on top is a standard GM unit. The one on the bottom is what I have, a Holley unit. You can adjust that GM unit. I thought the FAQ had directions?

lexum
03-13-2008, 11:38 AM
That's funny, I got the second picture from this guys "Howell" TBI site, http://users.california.com/~eagle/howell.html

I believe everything I read...

<Begin Speculation> All adjustments are intentionally removed from the Jeep Howell instructions to deter the end user from adjusting them. Seems like they will more readily send you a leaner chip rather than have you adjust their presets. <End Speculation>

I will grab another gauge to check the inlet pressure. I would expect to see a little more than 13 psi if the FPR is set to 12 and my return is 1. If it is 14 or 15 psi then I know the FPR is set too high. Then I will find the appropriate information to adjust the FPR. Probably in someone elses GM TBI manual.

Eric VanBuren
03-13-2008, 12:29 PM
That's funny, I got the second picture from this guys "Howell" TBI site, http://users.california.com/~eagle/howell.html

I believe everything I read...

<Begin Speculation> All adjustments are intentionally removed from the Jeep Howell instructions to deter the end user from adjusting them. Seems like they will more readily send you a leaner chip rather than have you adjust their presets. <End Speculation>

I will grab another gauge to check the inlet pressure. I would expect to see a little more than 13 psi if the FPR is set to 12 and my return is 1. If it is 14 or 15 psi then I know the FPR is set too high. Then I will find the appropriate information to adjust the FPR. Probably in someone elses GM TBI manual.
The Holley TBI body is a clone of the GM unit with there own FPR and injectors mounted on the top so that pic is valid as to the location of the min idle adj screw.

You bet they don't want you messing with the adjustments and learning how it works for fear that you learn that you could DIY it for a much lower cost and bypass them.


As to the FP adjustment, full directions along with detailed color pics are available right here in the FAQ.

lexum
03-13-2008, 12:47 PM
I found written instructions on another website. I do not see anything under the IHC FAQ under Fuel System for FPR adjustment.

I'm glad I paid Howell to pre-tune their system to match my Jeep, lol. I could have gone Junkyard TBI if I knew I would be doing all the adjustments.

lexum
03-13-2008, 12:52 PM
Nevermind, I see the InjectorTalk FAQ now.

rick W.
03-13-2008, 05:08 PM
I'm glad I paid Howell to pre-tune their system to match my Jeep, lol. I could have gone Junkyard TBI if I knew I would be doing all the adjustments.

Don't wory, you're not the first to make that mistake.....:dots:

lexum
03-13-2008, 05:17 PM
The fuel line in is a little less than 13 psi and return as I said before is 1psi. Understanding that the only reason that the computer would show rich and the IAC is closing means that the computer is at its limits of adjustment. I can only adjust the FPR or the program.

I guess this is somewhat good news because it indicates that my engine is in good working order and there are not vacuum leaks. I will let you know how the FPR adjustment goes and a quick BLM chart to go with it.

Thanks for the help guys.

rick W.
03-13-2008, 05:34 PM
The fuel line in is a little less than 13 psi and return as I said before is 1psi. Understanding that the only reason that the computer would show rich and the IAC is closing means that the computer is at its limits of adjustment. I can only adjust the FPR or the program.


I would adjust the IAC per the initial setup procedures in the FAQ. Afterwards don't forget to check the TPS at idle. May help the idle out a bit but won't make it any leaner at cruise. For that just do some adjustments to the main VE table using the BLM's as a guide or lower the FP a touch to get it in the right ball park....

lexum
03-13-2008, 06:52 PM
Well... the FPR has a little adjustment on it, but it is not easy to get to from under the TBI unit.

http://www.aquatab.org/photos/img_1243small.jpg

My FPR was pretty much maxed out...

http://www.aquatab.org/photos/img_1244small.jpg

I set it about halfway. Knowing that I may have to take it off again, I won't put new gaskets on until later.

I set the idle using the idle setting procedure. I loosened the TPS and tried to measure the voltage at B on the ALDL connector. No matter which way I twist it the voltage is always 4.98V with the ignition ON. I am awaiting the laptop(wife) to get home so I can verify this in WinALDL.

rick W.
03-13-2008, 07:26 PM
You're checking the input voltage to the TPS which if I'm not mistaken is supposed to always be about 5 volts. When you hook up winaldl check for about .54 volts with the throttle closed....You do this after setting the IAC because when adjusting the IAC you're moving the throttle stop position which also moves the TPS stop position...
Did you modify the FPR or was it already done before you got to it?

lexum
03-13-2008, 08:15 PM
The FPR was already modified by Howell.

I collected data but I will spare you the log files.
I am still just as rich and the IAC is still 0 at idle. I reduced the pressure regulator even further and got the same results.

The TPS at idle for the first test was .58.

I adjusted the idle for the second test and the TPS was .55 at idle.

At idle the BLM is 108 to 112 for both fuel pressures.

I'm done for tonight. Tomorrow I might go further on the FPR and try again.

Does the throttle plate shaft ever leak on these things?

rick W.
03-13-2008, 08:28 PM
I am still just as rich and the IAC is still 0 at idle.

I would adjust the IAC to where it does not quite go to 0 at idle. Maybe 5 to 10 counts. Maybe Bill has some input on this?


At idle the BLM is 108 to 112 for both fuel pressures.


How low did you go with the FP? I assume this is fully warmed up? Sounds like time for some chip work.

lexum
03-14-2008, 05:26 AM
I ran for about 30 minutes with the adjusted FPR at idle. There is just too much gas metered at idle. I dropped the throttle plate adjustment until the idle will not drop and the IAC never backs off.

I understand that this could also be a vacuum leak below the throttle plates. I have a new intake manifold gasket and I have sprayed carb cleaner all around the base of the tbi. I get a steady 20 in Hg manifold vacuum = pretty much rules that out.

I'm curious now that I may find the ECM already modified like the FPR was. I am waiting on the Moates adapter, but I might just crack the ECM open now and see what is in there. I have read on other forums that Howell has sent some people leaner chips to pass smog tests and there was never a mention as to whether they did any soldering work or needed an adapter.

Bill USN-1
03-14-2008, 08:32 AM
The FPR was already modified by Howell.

In what way?

I ran for about 30 minutes with the adjusted FPR at idle.
Adjusted to what psi?

I'm curious now that I may find the ECM already modified like the FPR was.
Why? The only mod that Howell normally does is burn a chip for the application...which brings me to the next question...If you bought this for your engine then why not just have howell provide you with the right chip?
Is this a second hand system?

You need to get the fuel close enough for the ECM to adjust it before worring about all the other stuff.
The engine is flooding..the IAC is not going to correct that and it is too rich for the ECM to adjust in closed loop if it ever gets to closed loop.

lexum
03-14-2008, 08:56 AM
My picture from an earlier post shows the FPR on my TBI unit. The casing of the FPR is all one piece, you cannot adjust it by turning the bottom part. There is an adjustment screw that controls the spring compression. I was able to turn the funny looking screw head with a flat head screw driver to adjust the level of the tab. Rick asked me earlier if I had added the modification to the FPR. I said no, it came like that from Howell.

I have not tested the return line pressure yet to see what the adjustment did. I will do that tonight when I adjust the tab all the way to the bottom.

You are probably right. Why add an adapter and a 29C256 if they only plan on swapping the chip once. I'm assuming they just take the stock GM ECM and switch the standard PROM.

I bought the kit new from Collins Bros. in Wylie, TX. They also sell the kit on ebay. I did send a message, detailing my troubleshooting, to Howell this morning and I am waiting to hear back. I wanted to make sure it was the program that is causing the issue and not my engine or setup before contacting Howell tech support.

Bill USN-1
03-14-2008, 09:55 AM
I'm not that concerned with rtn pressure but with inlet, unless you think the rtn is higher then 1psi.
You said the pressure was 13psi and then said you adjusted it....to what?

With the regulator upside down and adjusting the tab to the "bottom"...you are increasing the pressure.
You need to turn the screw clockwise and that will move the tab up which will lengthen the spring and reduce the pressure.

If you turn CCW it will move the tab towards the injector mount and increase pressure.

lexum
03-14-2008, 10:12 AM
Sorry, it is a little confusing when you flip the FPR upside down to tell what is up and what is down.

The Pump supplies 13 psi. Pump pressure - FPR setting(pressure applied to injectors) = Return pressure
Original setting:
Pump return is 1 psi, so FPR setting is 12 psi.
Right side up(bulb part of FPR down) the tab is at the top closest to the injector mount as pictured in earlier post.

Modified setting:
I am turning the screw CW which is moving the tab down (right side up) away from the injector mount.

The inlet pressure is always 13 psi. Knowing the Return pressure will give you the pressure to the injectors. I want the FPR to allow more pressure to bypass to the return line. So, which way does the tab go?

lexum
03-14-2008, 10:26 AM
I'll correct myself.

If the pump is at dead head while going through the regulator, the inlet pressure will remain 13 psi. The inlet pressure will decrease if the bypass is large enough to allow enough flow.

Anyway, I will get some pressure readings tonight and go further on the FPR adjustment.

Bill USN-1
03-14-2008, 10:51 AM
There's the problem..your line of thinking is off.


The regulator is on the outlet side of the injectors it will maintain the constant pressure to the injectors no matter how high the pump pressure goes.
The return pressure should always be near 0psi as it reflects the restriction in the return line and has nothing to do with the pump pressure.
Now if the rtn line is restricted it will override the regulator and cause the inlet pressure to rise.

So if you read the inlet pressure and pinch the return line...the pressure will go up.
Put the gauge on the inlet and set the pressure to 11psi and try it.
The tab should be away from the injector mount or down when viewed installed on the TBI.

You can then run it with the gauge connected and rev it up...if all is good the pressure should not change.

Then pinch the rtn line and see if the pressure goes up.

If good,
check the pressure in the return line.

lexum
03-14-2008, 11:55 AM
Doh!:death: If I had followed the flow path through the TBI I would have got this. There's a reason I posted on a newbie thread.

So the FPR was set to almost 13 psi, thanks Howell. Should be 12 psi and the 1 psi at the return line should not be enough to override the FPR.

I'll get that pressure gauge hooked back on the inlet side. Can I leave work now?

Are ya'll hobbyists or are you mechanist? Just curious.

lexum
03-14-2008, 05:08 PM
I installed the pressure gauge on the inlet side. Last night when I finished adjusting the FPR the pump pressure was at 10 psi and still 108 BLM at idle and IAC is 0. TPS is 0.55V. Guess I will adjust the FPR back to 12 psi and wait for the Moates adapter to tune. I should be able to get a good BLM chart and tuning done while I wait.

rick W.
03-14-2008, 09:03 PM
Are ya'll hobbyists or are you mechanist? Just curious.

<LOL> I'm a hobbyist and still learning at that. Bill is a seasoned pro...
Like Bill said earlier the IAC adjustment isn't going to solve anything. I just think that initial settings should be done before tuning. I do find it puzzling that the IAC counts don't rise when you close the throttle blades down lower that idle. Some time you may need to figure that out.....

lexum
03-16-2008, 06:14 PM
I pulled my ECM and took the cover off to prepare for the Moates adapter to arrive. Then I realized from Bill's instructions in the FAQ that I could just make my own.

Before I pulled the ECM I logged about 30 min of BLM data. I plan on doing some longer logs to fine tune. Again, I was 108 to 112 across the board even with the fuel pump at 11.3 psi.

I started tuning but I am not sure I am using the correct bin file. I chose the AKSU file which should be a 4.3L 5-speed bin. Anyway, I tuned up a bin using my BLM data and tunercat. I stuck it(the programmed AT29C256) in my ZIF on my loosely modified ECM. I didn't get any data on winaldl with the key in the ON position. I thought I read somewhere that I would need to use an offset when I load my bin, is this true? I stuck the Howell chip in the ZIF to verify that the ECM still works fine. It does.

BTW, this is the Howell CA legal chip for the I6 258. Hand written on the chip. I doubt I could pass smog here, I don't know how this would pass in CA.

lexum
03-16-2008, 06:23 PM
I wrote AKSU, I meant AKSN. I used the AKSN1175.bin

lexum
03-16-2008, 07:19 PM
Success... but still more ?s.

loaded my bin in tunerpro and stacked my bin using 4k bin, 32k chip, and 4k block sizes. I'm sure this can also be done in tunercat.

BLMs are hovering around 128 now. While cold, the idle went to 134 for a while. IAC is still 0 at idle after the engine warms up. There are two issues I notice that may be causing this:

1. If I back off the throttle plate screw the throttle plates never bottom out. If I then push the throttle plates closed, they will stay there and idle low. There may be some kind of restriction keeping the throttle plates from closing.

2. My idle randomly drops 50 to 75 rpm at idle every 5-10 seconds. It has always done this, even when I had the carburetor on. The carburetor could never recover like the TBI does. I have investigated this many times and the only thing I think I have not checked is the valvetrain.

I think 1 is the likely the culprit and maybe 2 is just normal for a barrel type fuel delivery system.

rick W.
03-17-2008, 06:40 PM
BLMs are hovering around 128 now. While cold, the idle went to 134 for a while. IAC is still 0 at idle after the engine warms up. There are two issues I notice that may be causing this:.
While cold? Is this after closed loop? How is your original over rich issue?......If I undrestand what you've done you now have a different bin and the IAC is still staying at 0? Is the throttle cable keeping it from closing?



1. If I back off the throttle plate screw the throttle plates never bottom out. If I then push the throttle plates closed, they will stay there and idle low. There may be some kind of restriction keeping the throttle plates from closing.

2. My idle randomly drops 50 to 75 rpm at idle every 5-10 seconds. It has always done this, even when I had the carburetor on. The carburetor could never recover like the TBI does. I have investigated this many times and the only thing I think I have not checked is the valvetrain.

I think 1 is the likely the culprit and maybe 2 is just normal for a barrel type fuel delivery system.

lexum
03-17-2008, 08:09 PM
I am setup to do fine tuning on the Howell bin. I extracted the howell bin and am using the BLM data from my previous log to modify the bin. It looks like I will have no problems getting a good AFR.

I did find that my vapor(charcoal) canister is purging at idle. I have ordered a new one. This should solve my idle issues and keep the engine from flooding when it starts. Once I have everything fixed I will report back and then start again with the HEI ignition module swap.

I am still having issues where the engine will fire (while cranking) around 500 rpms for a second and then die. Then I have to use the clear flood mode to get started again.

Could a small ported vacuum leak (vapor canister) cause the IAC to go to zero at idle and keep the engine from starting?

Bill USN-1
03-17-2008, 08:22 PM
The vacuum leak will affect the IAC position mostly when warm. but won't cause the IAC to keep the engine from starting. The IAC is parked at 145 when starting.
But vacuum leaks affect lots of other things like the map sensor readings.

lexum
03-18-2008, 02:45 PM
Troy gave me a call just a while ago. He is going to send me a leaner CA chip.

I am still trying to understand the flooding problem and what I can do to the bin file to fix it. I think there may be a possibility that the engine starts but doesn't get enough fuel at start to keep the engine climbing up to idle or higher. The engine dies while the remaining fuel jets into the manifold. When trying to start again, more fuel is injected and the manifold is already flooded. I then have to use "clear flood mode" to start again.

What can I do in the bin file to alter the startup fuel metering? I would like to play with less and more fuel delivery in the startup routine.

Bill USN-1
03-18-2008, 03:15 PM
You should not adjust any fuel tables until the main fuel table is correct.
All the other tables are added or subtracted from that one.
So if you are not logging data and have your normal closed loop fueling set to 128/14.7afr then you should not play with the others.

I think you are just too rich.

lexum
03-22-2008, 07:55 PM
Just an update on datalogging/tuning. I have found little time to do so, but here is my progress.

Original Howell BLM table (approx. 30 min run time on country roads)
http://www.aquatab.org/photos/original.jpg

Latest tune (just a quicky, forgot to print screen on previous longer datalog)
http://www.aquatab.org/photos/latest.jpg

I am getting closer and the gas fumes and burning eyes are less frequent.

I noticed a few constants in the Howell bin that looked "conservative" compared to a stock 4.3 GM chip. The Stoichemetric AFR was set to 14.2 while the AKSN_42.bin has Stoichemetric AFR set to 14.7. Open loop AFRs were also offset by 0.5. I am curious to see what the "leaner" chip from Howell has to offer.

It dawned on me that I could speed up the tuning process if I hooked up my LC-1 wideband that is collecting dust in my garage. I originally bought it to do some Honda tuning a couple years ago, and then I put a different engine in the car. Is there a way to hook the LC-1 into the ECM and get the wideband data through the ALDL?

Bill USN-1
03-22-2008, 08:50 PM
You can't just hook up a WB in place of the NB.
The WB is a 0-5v signal.
There are some add on circuits that you could use but I normally just start the LC-1 log at the same time as the data log. Then I can review them side by side.

I don't understand the 14.2 stoick. guess they wanted a little richer mixture to help prevent the lean roll at idle that happens some times.

lexum
03-24-2008, 06:16 PM
I got the "leaner" chip today. Doing a comparison with the original chip, Main Fuel Table #2 was reduced by 4.7 percentage points in each cell from 400 to 4800 rpm.

If I understand correctly, this is basically the same thing as selecting all of Main Fuel Table #1 and reducing those numbers by 4.7 points.

My concern here is that I am already leaned out on Main Fuel Table #1 (on my ongoing tune) more than this "leaner" chip. I am beginning to wonder if my FI kit came with the wrong size injectors. Is there any way to identify which injectors I have without taking it apart?

Bill USN-1
03-24-2008, 07:30 PM
Read the numbers on the top of the injector.
Then post the number up here.

lexum
03-25-2008, 05:37 AM
Unfortunately, there are no numbers on the top of the injectors. They are completely blank. All I have is some blue and yellow paint indicating the positive and negative terminals of the injectors.

Eric VanBuren
03-25-2008, 02:54 PM
The color is the size code, the injectors do not have a polarity. Do a search on TBI injector size the color codes and #'s are listed in a couple of threads. To see the part #s you need to remove the black rubber terminal seal from the top of the injector if it stays there instead of coming off w/ connetor. There should be a number that ends with a *rpd.

lexum
03-25-2008, 03:21 PM
Hah, I didn't think they had polarity, I just couldn't think of any other reason why there would be 2 different colors on each post. I did look under the rubber gaskets and there is no number. I found this on the search:

Color code Yellow/Blue
Engine 4.3L
Flow lbs/hr @ 13psi 45
TBI bore 43mm
GM part # 5235203

from here (http://www.binderplanet.com/forums/showpost.php?p=391364&postcount=5)

Looks like that one is ruled out. I think I am better off tuning my own chip rather than have Howell blindly tune my chips.

Eric VanBuren
03-25-2008, 05:55 PM
I don't understand the 14.2 stoick. guess they wanted a little richer mixture to help prevent the lean roll at idle that happens some times.


14.2 is the correct A/F ratio for Gasohol, EC100, oxygenated fuel or what ever its called in your area. Many states such as CA, OR, WA mandate it use of it under the guise of reduced polution. Apparently someone sold the right person on the fact that alcohol needs a richer mixture so adding it will cause the engine to run leaner. Of course this only works on vehicles that lack a O2 sensor and adaptive fuel control. It is normal to see BLM's or Long Term Fuel Trim indicating the addition of fuel across the board since it has been required year round in our area.

Check the pump next time you are there it will indicate "ethanol added" or "may contain up to 10% alcohol" in many areas.

rick W.
03-25-2008, 06:33 PM
Of course this only works on vehicles that lack a O2 sensor and adaptive fuel control.

Not sure I understand why this is?

lexum
03-25-2008, 09:38 PM
Eric, you completely confused me on that one.

Yes, I am running gasohol and I do understand this reasoning for 14.2 as stoich for gasohol. More ethanol (less air) is required to produce the same power.

Are you claiming that this is why my BLM table looks so rich? So...
128 BLM = 14.7 AFR
? BLM = 14.2 AFR

I have already changed my stoich to 14.7 in my bin. I tend to drive this vehicle out of the city more than in it.

Eric VanBuren
03-26-2008, 12:49 AM
Not exactly, I mean that in a rig operating on gasohol where stoich is set to 14.7 it is normal for a 100% stock perfectly operating engine for it to show that it has compensated as evidenced by BLM's or fuel trims that show the addition of fuel accross the board with an average of 5-10% added IE BLMs of 135-140 instead of a percent or 2 added or subtracted here and there. This is consistent amoung all manufactures. A few years ago a rig that was reading +10% fuel trim consistently would have indicated the need to check the FP or pull the injectors for a flow test and cleaning, now it is considered normal when looking over data for driveabiltiy concerns.

The BLM is the learned correction factor in the basic equation for determining the correct amount of fuel. The req fuel equation is really just a long chain of mulitplcation. The BLM # is divided by 128 (the center point of the range of 2 digit hex) and the resulting number is placed in the proper place in the equation. A BLM of 128 gives you 1 or no change and indicates the current tune achieves stoich with no correction in that cell. In simplest terms the BLM indicates how far off the current tune is away from stoich in any given cell. You must remember that the O2 sensor does not read A/F ratios, it indicates if the waste products were produced by a stoich combustion event or one that was too rich or too lean. Since you are tuning, 14.2 vs 14.7 doesn't really matter as it will all "wash out" in the VE table as you tune it to achive Target BLMs of 128. This will put you at the "center point" where the computer has equal potential to add and subtract fuel.

rick W.
03-26-2008, 06:08 AM
The BLM is the learned correction factor in the basic equation for determining the correct amount of fuel. The req fuel equation is really just a long chain of mulitplcation. The BLM # is divided by 128 (the center point of the range of 2 digit hex) and the resulting number is placed in the proper place in the equation. A BLM of 128 gives you 1 or no change and indicates the current tune achieves stoich with no correction in that cell. In simplest terms the BLM indicates how far off the current tune is away from stoich in any given cell. You must remember that the O2 sensor does not read A/F ratios, it indicates if the waste products were produced by a stoich combustion event or one that was too rich or too lean. Since you are tuning, 14.2 vs 14.7 doesn't really matter as it will all "wash out" in the VE table as you tune it to achive Target BLMs of 128. This will put you at the "center point" where the computer has equal potential to add and subtract fuel.
Thanks....This is the way I understood it also. The NB 02 only knows stoich regardless if stoich is 14.7........14.2 or whatever....I guess I just didn't understand your statement above. Now you say gasohol may be as much as 10% correction factor different from gasoline? Really? The reason I ask is I run my system open loop all of the time here in WA. Now if I take a trip to UT it may run a bit rich?...It seems to run fine now at very high elevations so I'm thinking it should be OK.

Eric VanBuren
03-26-2008, 11:52 AM
Remember I am looking at the data from these vehicles to try to find the cause of a reported driveability issue or emmissions failure. I think the actual correction is about 4% but add that to the acceptable +/- 5% and you can end up with a vehicle that shows a lot of areas with the LTFT or BLMs indicating additon of near 10%, while others may end up showing zero. In the past a +10% was "way high" where w/gasohol its "a little high".

The adaptive fuel control is the reason that they can get away with 10% alcohol. The lack of it on some carb rigs caused a fair number of HC failures when "oxygnated fuel" was first introduced and neccistated the rejetting or raising of the float levels to richen the vehicle enough to pass. So much for the cleaner air aspect, since it leaned out all vehicles equally w/o adaptive ability those that were running right on the edge of stoich already were suddenly too lean and actually "dirtier" than before.

lexum
03-29-2008, 08:32 PM
Alright, back to the original topic of this post...

I think we have a good lead on Keith's flooding problem. I met him this afternoon and checked out his rig. First thing we noticed is that his engine cranks very slow. I checked his battery voltage while cranking and it drops to around 9.5 Volts. First, I thought maybe his battery is bad. He said he had it tested okay. Later, I realized my mistake. He probably has a bad alternator cell!

I think we have already come to the conclusion that there is no telling what the ECM will tell the injectors to do if it doesn't get 12V while cranking.

We jumpered my battery to his which improved the situation, however, cranking was still very slow and we all know how hard it is to start an engine when the starter is slowing turning the crankshaft and the sparks are playing "marco polo".

This possible solution is pending an alternator change.

I got some very useful information from this meeting. Keith's 258 runs rather well with the Howell chip. Based on some of his earlier BLM tables with the astrovan chip, the Howell tune looks like it is correctly tuned for his engine.

I am back to looking for mechanical problems that could cause my engine to run rich. I have no vacuum leaks, compression is good, all cylinders are firing, spark plugs are new with light carbon soot, pcv valve is new, egr valve is new, o2 sensor is new, tps reads 0.55V, air filter is new, iac works, coolant sensor works, charcoal canister is new, TFI coil is new, ignition module works, timing is good, and mechanical advance works.

I ran some seafoam today to try and clear out any carbon from my recent tuning runs and found a small exhaust leak immediately after (1 inch) the o2 sensor. Even if it was before the sensor, that would cause it to read lean.

Those of you who have TBIs... At idle, do you see fuel dripping along the throttle body wall down to the throttle plates when you idle?

I am pretty certain that all fuel delivered from the injectors should be immediately sucked past the plates. It's a long shot since both injectors appear to be delivering the same pattern of fuel, so I doubt that both are working incorrectly.

What is the best way to force open loop so that I can troubleshoot engine problems without computer interference?

rick W.
03-29-2008, 09:33 PM
I ran some seafoam today to try and clear out any carbon from my recent tuning runs and found a small exhaust leak immediately after (1 inch) the o2 sensor. Even if it was before the sensor, that would cause it to read lean.


If the O2 senses oxygen from a exhaust leak the ECM thinks it's running lean and will compensate by adding fuel= richer.

rick W.
03-29-2008, 09:36 PM
What is the best way to force open loop so that I can troubleshoot engine problems without computer interference?

You should be able to just unplug the O2 sensor.

lexum
03-30-2008, 07:00 AM
If the O2 senses oxygen from a exhaust leak the ECM thinks it's running lean and will compensate by adding fuel= richer.


Yeah, but I am having the opposite problem. My O2 sensor is reading rich counts and the low BLM indicates that the computer is trying to lean the mixture. So I don't think the exhaust leak after the O2 sensor has any effect.

lexum
03-30-2008, 08:23 AM
Keith's fuel table from astrovan
20 30 40 50 60 70 80 90 100
400 16 19.1 21.9 30.1 36.7 41.8 46.9 46.5 55.5
800 19.1 25.8 34.8 39.1 43 45.7 46.9 49.6 57.4
1200 23 32.4 41 46.5 48.8 50.8 52.3 54.3 58.6
1600 28.1 37.1 42.2 47.7 50.8 52.3 54.3 56.3 61.3
2000 35.2 41.8 44.5 50 53.1 54.7 55.9 57 61.7
2400 42.2 44.9 48.4 53.9 55.9 57 58.2 58.6 62.1
2800 44.9 48 52.3 55.9 57.4 59.4 59.4 59 61.7
3200 48 51.6 54.7 58.2 59 60.5 60.9 60.2 62.5

Keith's BLM table from astrovan
Narrow Avg
RPM \ MAP 20 30 40 50 60 70 80 90 100
400 0.0 0.0 0.0 126.0 0.0 128.0 0.0 0.0 0.0
800 0.0 126.2 127.8 0.0 134.0 0.0 0.0 0.0 0.0
1200 120.8 116.4 124.1 125.1 130.5 137.4 150.0 0.0 0.0
1600 114.8 120.3 127.4 128.5 134.2 140.2 138.0 127.8 0.0
2000 120.1 127.9 130.4 129.4 134.4 137.6 131.3 0.0 0.0
2400 124.7 130.1 135.7 136.3 135.0 131.3 130.0 129.0 0.0
2800 0.0 137.0 133.1 135.6 136.1 136.4 133.0 0.0 0.0

My current tune and still leaning....
6.6 12.9 18.0 25.4 31.6 37.9 41.8 44.9 50.4
9.0 16.8 22.7 28.5 34.8 40.6 44.5 47.3 51.6
11.7 18.8 28.5 31.6 37.5 42.2 45.7 48.0 52.7
13.7 20.3 28.5 34.0 38.7 43.8 45.7 50.0 53.9
16.8 24.2 33.6 34.8 44.5 48.8 49.2 50.0 54.7
21.5 29.3 35.9 37.1 42.6 47.7 49.6 50.4 54.7
31.3 35.2 39.1 40.6 46.1 48.4 48.8 50.4 56.6
35.2 37.9 43.4 44.5 47.3 50.8 52.7 53.9 59.0


My current BLM table
Narrow Avg
RPM \ MAP 20 30 40 50 60 70 80 90 100
400 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
800 0.0 116.9 0.0 122.0 0.0 0.0 0.0 0.0 0.0
1200 0.0 122.6 0.0 0.0 122.5 0.0 0.0 0.0 0.0
1600 114.5 118.2 111.2 111.8 115.1 112.7 109.0 135.5 0.0
2000 118.0 115.2 122.2 120.1 110.9 116.5 137.5 119.0 0.0
2400 0.0 114.0 127.5 0.0 139.0 122.0 0.0 0.0 0.0
2800 0.0 0.0 0.0 0.0 0.0 0.0 0.0 139.0 0.0

lexum
03-30-2008, 10:03 AM
The O2 sensor on the early wranglers is on the exhaust manifold about 1 inch before the exhause pipe flange.

The seafoam treatment leaked at the flange on one side. I was only able to tighten the nut on that side about 1/2 turn more. I went datalogging this morning and my entire BLM table was above 130 BLMs, a couple cells were as high as 150.

Time to start over with the base bin. I'm glad I finally discovered this. My engine was starting to sound like a race car.

I recommend seafoam as a great way to find exhaust leaks because the smoke will come out of any leak in your exhaust system. I found a pin hole further down the pipe. I have had an exhaust "specialist" look for leaks in my exhaust and even he did not find these leaks.

Keith Miller
03-30-2008, 10:35 PM
It looks like my problem was mainly my starter. I have installed a loaner and the motor turns over much quicker, and I am able to warm start with very little trouble. It still needs a little longer to crank than I prefer, but at least it starts.

Thanks for the help on Sat. Justin.

One more trip to the parts store.

lexum
03-31-2008, 09:09 PM
Here we go again...

First, I'd like to retract some statements from post #73. The Howell tune did NOT work well in Keith's 258. It ran just as rich as mine does.

After losing tons of sleep over my tuning woes, the problem dawned on me while I was cruising around datalogging with the astrovan bin in my chip. Recall from the previously posted BLM table from Keith's rig, he runs just a little lean at the bottom right portion of the table. I run about the same just scaled a little richer but the best tune I have run so far. His setup is slightly different than mine; less exhaust restriction, no charcoal canister on his ported vacuum, and electronic timing.

So I figured out the trouble I am having tuning off the Howell bin. Fuel table #2 is not smooth. This means Fuel table #1 is not normalized. Looking back at Bill's FAQ on tuning, I see now why I have had so much difficulty smoothing out Fuel table #1 on the howell bin. So if I used aldltobin to make adjustments and then smooth out FT1 I am actually making the table worse.

My theory is that Howell tunes the FT2 to get "in the ball park" values for an engine and then fine tunes FT1. This is consistent with the leaner chip they sent where they only adjust FT2 to make a leaner chip.

Needless to say, I datalogged and tuned using the astrovan chip which has a very smooth FT2 and I now have 128 BLMs +/-2 in every cell after one adjustment. Just in time! I have to smog next month.

If all goes well, Keith will be up and running with the same results. Thanks for the input guys.

Bill USN-1
04-01-2008, 11:41 AM
If you look at table 2 it is a single column based only on rpm. So it's easy to just highlight the entire column and reduce it.
So if Howell leaned the fuel with FL2 then it was probably out of convenience.

Keith Miller
04-03-2008, 10:14 PM
Well, Thanks to everyone's help, especially Justin and Bill, I finally have the bugs worked out of this Junkyard TBI installation. The biggest problem seems to have been the starter. After meeting with Justin, we decided that the low voltage to the ECM during cranking must be the culprit. I had previously had the battery checked at the auto parts store and was told the battery was fine. A swapped out the starter and Wa La. She starts up fine now. The new starter cranks the engine much faster and with more authority. Justin sent me a re-programmed chip which modified the original Asto-Van tables and the initial review of the BLM table looks very promising. I'm not an expert at reading the tables, but the majority of the cells appear to be between 125 and 130. I'm going to send this table back to Justin and see if he wants to make one more tweak.

Many thanks to everyone for the assistance with getting the problems worked out. When I first started this thread Bill suggested I check all my voltages and I knew way back then the ECM voltage was low during cranking. I just wish I had run that problem to ground before messing with everything else. It really took hearing another 258 cranking to realize my problem wasn't with the TBI, but just a basic engine problem. Funny, I never had starting problems with the carb.