Lean until warm (more IAC issues?)

[scorp1us]

It seems from a cold-start she runs lean until she warms up. But here is the thing. I have to turn it off, then start it again when she is warmed up to get the lean condition to go away. (I'm assuming lean because she's backfiring through the TB) After the restart - mere seconds later, she runs like a champ.

I replaced the CTS.

I am guessing my IAC likes to be more open than it should, which is why I am running lean. I'm guessing the computer is trying to have me idle higher than what I have the throttle plate set for. But here is the question: should I open the throttle (via the torx screw) or close it? Opening it will have me idle higher. Closing it will make me richer, which would counter-act the over-opened IAC. It seems that I need to match the computer-designated idle RPM for the IAC to behave properly. I'm thinking if I open it, then the IAC will close more.

I've started with the IAC closed several times now and this keeps happening. At least it's consistent.

[Bill usn-1]

Have you logged any data or done any voltage checks?

The minimum idle screw should be set and forgot.
There is no need to use it to try and correct for a tuning problem.
It is normally set just off of fully closed. About the thickness of a sheet of paper slipped between the center of the blade and the body.


I don't remember seeing any data logs or BLM data from your system.
Last I saw you needed to build a 2 trans cable or buy the right one for the PCM.

[scorp1us]

I'm working on attempt 3 of the cable. One problem is my harness didn't come with a connector, so I don't know what connector I should have. The system is out of a 94 5.0 which by the book is 16 pin... But it could be 12. Which is now running in 1995 5.7 ECU.

Moral of the story: pull the setup yourself.

Sometimes you need a 10k resistor too. Which all might explain why my IAC doesn't shut when I short the pin.

[Bill usn-1]

You don't need the 10k with that pcm to initiate comms.

You don't need the aldl connector unless your buying a cable with the other end that just plugs in.
All you need is to make the 2 trans cable and connect the serial data wire from the ecm and the ground.

[scorp1us]

Whoo hoo! i got it working!

Here's my adl file. It is of a warmed-up engine. It did do the pop thing once.

I'm using TunerPro RT and I don't know how to get to the knock /BLM table...

I did watch the dash - 50 knocks, always on the rich side (114 at the richest) IAC is moving (or so it thinks)

[Bill usn-1]

So what did it take?
Did you make the 2 trans cable?

The log I looked at only showed the basic data and a count of 1, Very short.

[scorp1us]

Yeah, the 2 trans cable with +12V. Somehow I got "connected" in blue in TunerPro with the 1 trans cable and that threw me off. (But there was no data)

Now I get data.

Well the file is 1.3megs I don't know why it is acting like it only has one sample.
I'm using a $OD cal 0 which should be fine because the other data is valid.

I'm looking into it more today.

[Bill usn-1]

Did you play the data?
Does it run for you?
Being an adl file I assume you have TP4.

[scorp1us]

It seems the file was corrupt. Each session goes in the same file until you change the file. So since my data connection issues were first, it corrupted every session in it.

I did another run today. Fresh file, Attached. Three sessions:
1- highway
2- blank.
3- 40mph road - one pop a minute or two from the end.

Yes, TP4. I tried 5, but I confused me on the data connection stuff.

One thing I did notice on the highway run is at WOT, it wasn't going faster than 3200 RPM. Only a slight incline. Whereas I got it up to over 3500 moments earlier at partial throttle.

[Bill usn-1]

I played the new log and tried several ads files but none of the TP4 files showed any histograms.
Makes it a little difficult to get a good view of what the engine is doing.
Have you downloaded TP5 and tried logging with it?
It looks like it has some up to date OD ADX files.