Well this all started a while back when I was just cruising around on my new motor (800 miles on it) and my car just lost power and stalled, and would not restart.



Well a month of troubleshooting later and its still doing it.


Compression = ok
Fuel pump is getting full voltage...

the car starts..revs to like 2k or 1k, and then sputters out or dies immedialty. its getting spark, the injectors seem to be ok, the cas is ok, the fuel pump ground is ok... i dont have a fuel pressure checker so im not sure about that..


but if while im cranking it i hold the pedal to the floor, it wont try to start.. but right when i let off the pedal it will start and rev higher (like 3k) and then stall again.

im just lost and im not sure what to check next.

 

can you push on the gas and keep the rpms up or does it just stall? If so, does it stay running after its warmed up?

 

nah if i touch the gas it stalls

 

Are you sure your injectors are hooked up right / not leaking?

 

they are hooked up right, and im pretty sure they arent leaking

 

Got a "check engine" light?
My guess - you get code 2 - AFM.
Maybe a loose AFM connector?

 

no check engine light on s4's, but i did check the ecu for codes and it gave me none. the starter is fine (the engine is turning over and starting.. then sputtering out)

and the sparkplugs where the first things i changed =/.

and then afm is plugged in and the afm tested out ok

 

How old is the fuel filter??

 

i just put a new fuel filter on 3 days ago =[



how would i test the alt?

 

That's kind of tricky.

I would just go to autozone. Buy a new one or rebuilt one and then keep it real nice and shiney.

Replace the alt and then if problem solved. Viola you're good to go. If not, put it back in the box and take her back for a refund.

I would normally suggest to take your alternator to autozone and have them bench test it. But after having a bench test on a faulty starter that I had that worked fine on their bench, but not in my car, I have little faith in their testing abilities.

 

i really dont think my alt is bad.. because when my car is running for the 3 seconds before it stalls, the voltage on my battery jumps up to 13-14 volts


then drops back to 12 when the car stalls

 

Here's a thought - the fuel pump pickup filter (sock).

A theory:
Any loose debris in the tank will wash off the sock, then as fuel is delivered, it gets sucked back up to block the sock.

I know it's a lame theory - but maybe?

 

Vacuum leak? TID fall off? Cracked intercooler hose?

 

no vac leaks that i can find, tid is still attached, and all the intercooler hoses are fine. =///

 

Try jumpering the fuel pump test connector. Yellow 2 prong connector by the pass side strut tower. This will allow the pump to run without the signal from the ECU, which seems to be your problem.

Jarrett

 

j-rat, even when i did that the car still sputters out




... and sureshot thats what i was thinking, the intank filter... but the 6 screws on my fuel pump are going to be a very major pain to get out, they are just basically rust piles

 

Then I gotta side with AAron on this. Bummer.

Did you use your ECU tester lights to ensure the ECU was coming online?

Jarrett

 

well... the ecu check lights both light up for a second or two right when i put the key into the on positition... but they are sending no codes.

 

and as far as i can tell there is no leaks between the afm and turbo

 

well another thing that could be bad....


i have a rebuilt engine from an 87 t2.. and my car is an 88, and i have high resistence injectors (12ohms) and the 87s used low resistence, right? i dont know what ecu i have either..


but the car ran fine before it quit on me, i had put 800 miles on it.

 

Maybe this is not of any value, but just because the pump is getting voltage, and the filters are new, doesnt mean the pump is flowing enough fuel. I'd say get a fuel pressure gauge, and do a flow test carefullly with the fuel line dissconnected from the engine. Sounds to me like not enough flow.

 

yeah i was kinda thinking that.. i needa get my hands on a fuel pressure tester

 

This could be it. I've searched and some people think it will burn the ECU up and others say it will **** the injectors up. My friend put some of my low impedence TII injectors into his 88(high impedence) NA and it ran fine for a while. And then is started running like **** and he changed them back and it was fine. There is a number on the ECU I believe, someone on here will know which one correlates to which year. I'm not sure myself. But you have the little resistor box right? In the front passenger side corner, behind the headlight?

 

yeah theres a little box up there with a resister and what looks like a relay

 

Maybe this is it then. Because my friends ran like ****, but he had only secondaries in there. If he had primaries too his **** would probably not even ran at all. Just get to your ECU and see what number is on it and then someone will know if you have the right ECU or not.