Custom EFIs

[bmalta]

OK, now I'm thouroughly confused (just when I thought I was close)!? I rebuilt the regulator with a new diaphram and seals, and adjusted the tab to the top of the slot for max pressure according to the FAQ (it was near the bottom).

And what did this do?

Almost nothing as far as the pressure is concerned and now it runs even worse, stumbling and backfiring with moderate to heavy acceleration. I want to blame the pump, but I can't make sense out of how it can attain pressures like 80psi when the return line is pinched, but can't exceed 6-8psi via the regulator. (BTW spring appeared stout, and similar to a friend's that I used for comparison).

Please shed some light in this darkness.

[Bill usn-1]

If you have a compressor I would hook a hose the inlet or blow in the inlet and see if you have any restriction.

What pressure does it show?
There's only 2 parts. The regulator and the pump.
So see if you can adjust the pressure. If you can with the air then the pump is weak.
If not then you need to look at your regulator assy and TB.

[bmalta]

OK, when things don't make sense, look for the obvious:

I changed the in tank sending unit while the truck was laid up, and the gas was low in the tank... I added 5 more gallons of gas and suddenly was able to achieve 10psi! I'm guessing that I didn't get the pickup to the bottom of the tank and to make matters worse I was test driving up and down a hill (so I could coast home when I stalled). I suppose I was just starving the pump.

Now it starts much stronger, idles well, and runs!! However, it still stalls and stumbles. I couldn't create a clear pattern, but it appears to be after giving alot of gas and coming to a stop or slowdown. I'll gather some data and post. I will also have my Alt tested, as I suspect low voltage to pump can be compounding isses. Need to also check my sparkplugs and pressure under load. More to come. THANKS!

[Bill usn-1]

lol
I can't predict the level in the tank.

But 10psi is still low.

[bmalta]

I took a quick ride around the block before going on a longer data collection run (that I planned to involve a trip to AutoZone to chk the alt). Pulled into my garage to get something I'd forgotten, and as I put the car in reverse to leave, discovered that I no longer have reverse!

Apparently my fuel issues will have to be temporarily put on hold.... Am I the only one that wonders why we like old cars?

[Ethan B]

Fluid is probably low. Or filter clogged. The TF 727 is a pretty tough transmission, IMHO.

[bmalta]

Thanks Ethan, I hope you're right. I was on my way to work when this happened so I didn't have the ability to investigate. I plan to drain and refill the TC and tranny tonight.

Low fluid wouldn't surprise me, but how would it affect reverse gear only??

[Bill usn-1]

HMMM, BTDT.
You may want to do a search for "no reverse".
I did a write up here or on Justih.
Mine was the reverse servo.

[bmalta]

Ok, even though I'm down, I'm not completely out. While fooling around with the transmission, I also plumbed my fuel gauge to the return side of the TB and verified zero psi on that end. BTW intermittently my idle will be high and not kick down unless I key off and back on again.... I guess a VSS would fix this but I don't think it should be happening in the first place.

WRT the tranny: fluid was over a qt low, but filling it didn't change a thing (in any gear). Since I needed to heat it to fill and check, and it needs to be cool to change, I will have to wait until tomorrow before I'll pull the pan and get a visual internally. According to my service manual, after low fluid, a mis-adjusted band aerated fluid and bad servos are the next likely culprits.

[bmalta]

I searched for no reverse, and similar entries and found a fair amount of info, most of which pointed to the write up that Bill did.... However, all the links to that post seem to be bad or dead links??? Am I doing something wrong, are they archived and I don't know how to access?

I also had a chance to drop the pan, and get a look inside: The fluid was still reddish, it didn't smell burnt, there were lots of iron filings below the filter and a few chips/flakes above, but they didn't appear to be significant. (pictures attached).

I have a question on the Rear Band adjustment: The initial condition of the band is loose/floppy. When I snug up the threaded stud, and back off 2 full turns I'm right back to loose/floppy. Is that normal? Or does that point to my problem??