Warm stall EFI problem, Auto trans

Hey All, I'm having a bit of trouble with a Bronco that has EFI installed and it's a wierd problem. I've had Mustangs and converted Broncos, etc with idle issues and stalling when cold, but this is different.
The Bronco has a '95 Mustang motor and AOD, with a Telorvek EFI harness. All systems work and no trouble codes. Starting cold, it fires right up and you can go into reverse or drive gears and you are off to the races. No issues there. However, once warm, say if you pull in to the station to fill up the tank, and then go to restart it, it will start fine, but will die when put into gear. Restarting it and putting it back into gear it will be fine. It will only do it once. I've been able to get past the stall by revving the motor once and then putting it in gear...it wont stall that way. So far we've set TPS voltage new IAC motor, cleaned TB and MAF, and have installed new O2 sensors. Any other thoughts on what could cause this? Otherwise smooth idle and rock solid reliability.

I have had similar running issues in the past where it would run perfectly most of the time, but sometimes when it was hot it would stall and sputter and have no power. I determined that it was fuel pressure building in the return line (mostly from heat) and it was impacting the FPR on the rail. I rerouted my return line away from any potential heat source and it never returned.


Hope this is helpful.

Rich

Do you have the VSS or speed sensor hooked up correctly into the computer?
IIRC it needs this to operate the IAC correctly...

Good suggestions guys. We are wrapping the pipe and fuel filter as a first step.

Subscribing.....my 351 EFI with a chip does the same exact thing.....very often at the gas station as Andrew mentioned. The guy who tuned my rig and installed the chip swears it is nothing in the tune, he steadfastly says it is IAC failure. I have swapped IAC's but haven't spent a bunch of time to figure it out. Hope you do and I'll let you know if I come up with the fix.

Is the tank vented to a charcoal canister? If the tank is unvented, you MUST run a vented cap or there can be some vapor lock, and will do as you described also.

Also, what condition is your ECT sensor and TFI module?

Sounds like an issue with the IAC or dirty throttle body/MAF.

Not a problem with tank venting if the tank was just filled and vented. VSS has no output when stationary.

Yeah, now that I read that more closely it does sound electronic related. What ECU are you running, the A9P? You're running the AOD and NOT the AOD-e correct?

Without knowing much about your setup or if you are running a custom tune, one area I would suggest you research is the ACT (Air Charge Temp). If that sensor is in the #5 runner, it can get heat soaked and potentially result in some of the behavior your experiencing. Most folks running a custom tune move it from that runner to somewhere in the intake tube, and then make the needed tweaks to the tune to account for the new spot.