Tonight when i was driving home, my 87 t2(s4 motor s5 turbo emission deleted) died on me, and trying to start it resulted in it to not stay running, only 2 ish seconds before it cut off and died. with my limited tools and time i checked the tps sensor, plunger looks good, checked connection on the afm, checked throttle cable and butterflies.
Only got the car to run and respond to throttle by propping open the afm and jumping the fuel connector.
Anybody have suggestions on how to start diagnosing this issue? Seems to be a fuel pump safety shutoff related issue.


TLDR
87 fc t2 only runs for 2 seconds before dying, only runs when afm is held open and fuel connector jumped.

 

I really can't help much but ohming out the wiring from the ECU connector per the FSM would be a good start. You can find misbehaving items rather easily.

 

been unplugging things looking for changes, discovered that when the afr is unplugged the car runs pretty normally, minus it sounding a bit rough. could this mean a bad afr or is it just tricking the ecu to run the car normally?

 

You should probably try testing it. Although, I have no idea what an AFR even is.

 

maybe it’s called the maf? it’s got a spring loaded plate inside to measure airflow, big silver box thing. unsure how to test, only have access to a multimeter

 

I just did the test myself. A sweep test is needed as well. A multi meter and the FSM is all that is needed.


I did a sweep test from E2 to VS. Push the door from open to closed smoothly and look for jumps or dropouts.

https://www.rx7club.com/2nd-generati...sting-1167365/

This is my thread here. I never got an informed response if my test was good or bad. I assumed it was bad. An analog meter is easier to see what is going on.

 

i’m in bed at this point lol, going to try tomorrow. did yours fail or not? if so were your symptoms similar? i’ve already found a replacement if so

 

My car has idle issues and the 3,800 hesitation. The TPS was never set correctly wither. I haven't even warmed the engine to normal operating temperature since 2012.
Do a search for AFM here. There are many threads with this similar issue. An AFM can fail in many different ways. My thread with the sweep test is the only one that is on the site as far as I know.
I never got a the response from any senior members here with the experience of sweep testing to confirm my suspicion. In threads here it stated, even if the AFM passed the tests listed in the FSM, it doesn't mean that the AFM is any good.

 

You should start by checking for vacuum leaks and ensuring that your vacuum system is correct and functioning. Your idle air is primarily supplied by the air bleeds for your oil injectors and fuel injectors. It is then moderated by the ecu using the BAC solenoid. The small air bleeder on the BAC is the fine idle air adjustment.

If the throttle body has been messed with, restore it to the original state.

As far as setting the TPS, the only reason to warm up the engine to set this is to disengage the thermowax that holds the throttle open until the engine is warm. You can set it just the same if the cam is not preventing the primary throttle plate from closing. With the primary throttle plate closed, you can set your tps. You should only have to set your tps once. This isn't like adjusting a carburetor. You set it once the right way and its done.

 

just replaced the afm. didn’t change a thing, car runs with it disconnected, but the second i plug it in, dies after revving up for a few seconds. i’ve extensively gone through my engine for vacuum leaks, nothing, throttle body is set properly. IDK if this is any help, but i cannot use the throttle to make it hold idle, i can’t press the throttle in far at all without it making the car die.

 

I am kind of surprised that you replaced the part without posting results. Putting this car through a parts cannon is costly and not advised. I kind of lost track of the threads that people checked for leaks and still missed them. If you used a smoke tester, the torch fuel method or the starting fluid method, I would be more convinced. If you don't want to check for leaks again, check for codes and/or start ohming at the ECU. You might have some bad wiring. There aren't many options left as far as I can tell.

Edit: Engine and sensor grounds are very important too!

 

i smoke tested. yeah a guy rly near me had a afm i could borrow lol. i fixed the issue tho, i did a little more reading on this issue and people were talking about fuel pressure. that clicked in my brain and i knew exactly what was wrong, rubber fuel hose between the metal pipe and fuel pump had a hole in it 😭

 

I am happy it clicked in your mind because it didn't for mine. I would have not guessed a fuel delivery issue.This will be a lesson in trouble shooting for me, thanks. Nice work finding the issue. Enjoy your car and be safe.

 

Big thanks for your time and replies, and same to you!