Ninja636

iTrader: (2)

Hey all, i picked up an 88 AE T2 fresh rebuild with a "stage 2 street port" that I'm having idle trouble with, the car starts right up and runs for 20-21 seconds (i used a stopwatch) then shuts off, i can do this over and over again and it's the same outcome, engine hot or cold. RPM's shoot up to about 3k then bounce between 1300-1500 and after 20sec it shuts off, if i hold the throttle over 2k it will keep running steady but seems to hesitate when pressing and depressing the throttle.

What i have done so far:
Checked volts and Ohms on TPS they are within FSM range
Cleaned and bench tested BAC, 12v to the connectors activates the solenoid. Unplugged or plugged the BAC doesn't make a difference on the 20sec shutoff
Had to manually screw in the idle adjustment screw near the firewall, this was the only way to keep the car running otherwise it would start up and die
Vacuum looks good couldn't find or hear any leaks and the stock gauge has the needle all the way on the bottom post when running, boost also builds quickly
Tried separately jumping the yellow fuel pump test jumper and the green Initial set coupler jumper, that made no difference on the 20sec run time.

professionalpyroman

How is your fuel pressure? I see you ran your fuel pump, but no pressure numbers. Have you checked out your pump and fuel filter?

Are there any codes in the ecu?

TII777

iTrader: (2)

Could be AFM sensor. A bad AFM sensor can cause all sorts of issues both in idle and under load. A common symptom of a bad AFM is dying after start up. Do a search and you can find procedures to test it with a multimeter. If its bad let me know. I have a good S4 turbo AFM I can sell ya.

Ninja636

iTrader: (2)

Solved! (i hope)

Hey all, just wanted to update this thread in case someone in the future has similar issues and finds this post. Thank you professionalpyroman and TII777 for the suggestions.

Last week i had some free time and tested some more of the components and replaced the fuel filter as mentioned above and was still getting the same issue. Running out of ideas i borrowed my buddies higher end smoke tester that works under pressure and ran another vacuum line test, this time after about 5 mins of it running under pressure we saw a steady stream of smoke coming from a slit in the turbo inlet pipe before the turbo housing and after the AFM which would mean a good amount of unmetered air was getting into the system causing the ecu to not supply enough fuel, well at least i think thats how that works. We used some fancy aviation glue that works on rubber to seal the opening and she fired right up and ran great, idle is smooth and power steering starting working too yay! Now i need to solve my boost creep under load.

Although the inlet pipe seems to be holding up just fine i would like to get another one without damage just in case, does anyone know if there is an aftermarket option or is oem the only way to go?

Molotovman

iTrader: (49)

Is the car 100% stock or modified? Stock vs. Standalone EMS matters.

Also, the fuel pump my just be bunk. It may pressurize the rail to start the car and then be unable to supply adequate pressure, if it's the stock pump it is 37 years old at a minimum.