Car starts for a minute, then dies. I have a theory
 

So I recently bought a fully built 1988 Atkins Turbo II. Its running a FMIC, Tiel BOV with some odd wiring attached to the MAF, I'm assuming so that the previous owner could run a BOV with the MAF. It has a GM turbo from a turbo-diesel truck. He is running the stock fuel rail with some RC injectors. And a full turbo back 3" or so exhaust.:icon_tup:

I can't get the car to run for more than a minute. After it runs briefly it will die. I try to start it again and it wouldn't start but had a HUGE back fire :shocking: . So my theory is that the injectors are too big for the stock fuel system.

I sold my DSM to buy this car, which makes me cry :icon_no2: , and I am not totally certain what the capabilities of the car are. Can the stock fuel system adequately handle what I assume must be much larger injectors?

I was going to start diagnosing this problem with some smaller, perhaps stock injectors. Does that sound good?

The BOV is not an issue unless it's leaking.

What else can you tell us about the mods? what ECU?

It could be something simple like the AFM flap stuck part open, or a leaky injector, or a pinched fuel return line.

I read something about that being a possible cause. However, when I search AFM I can't find too much on what it is or where. I hate to be the noob asking that question here but I will.

What is the AFM, where is it? Or could you link me to a thread that has it listed. I read the FAQ and had been searching forums because in other no start threads its always referenced.

AFM = Air flow meter, In some cars it's aslo called the MAF (mass airflow sensor).
It's betweem the air cleaner & the TB (throttle body).

There is an abbreviation guide in the FAQ thread at the top of the forum.

Could also be a clogged fuel filter...

vacuum leak or bad idle adjustment is my guess. does it stay running if you hold the gas down a bit?

What runs the car?

Stock ECU? Haltech? SAFC? etc.....

Stock ecu won't handle bigger injectors very well since it thinks 550's are there.

What size injectors?

Not starting after it dies sounds like flooding.

Yeah its definitely flooding because it backfired. The injectors are just bigger, thats all I know. I am taking off the "dynamic intake" I believe it is called, tonight so I can get the injectors out of there. It is being powered by the ECU.

As far as the AFM goes, I wasn't aware it was actually a flap and not a sensor? So I should take the intake apart and make sure its closing properly?

As far as vacuum leaks, wouldn't it not be leaking until the car was running and under boost? If not, where are probable leak spots on '7s

(PS: I knew the AFM was air flow meter, but I didn't know it substituted the MAS in traditional vehicles)

no it doesn't stay running if I pedal it.

I would put stock injectors in the primaries find out what ecu your running. Also check fuel pressure with tester after it starts and dies it may have bad fuel pump resister or relay. Clean plugs do the d fouling procedure.:fingersx:

best place to start is to hook up a fuel pressure guage as this can point to several possible issues.

fuel pressure should be from 32-42PSI, depending on if the fuel pump was upgraded or not it should be near the low end at idle.

if the fuel pressure starts to drop off before the engine dies then you will have to find the cause, either the pump is turning off and residual pressure bleeding off is causing the engine to stall or the pressure is being restricted somewhere. there is a switch in the AFM that controls the fuel pump operation, if there is a large enough of a vacuum leak then the AFM flapper closes enough to cause the switch to close again and turn the pump off.

more than likely if that is the case you have either a vacuum leak or a plugged fuel filter or a pump that is dying.

if the pressure is constant even when the engine stalls then it is likely too much fuel via large untuned injectors or the timing is severely off either at the CAS or some spark plug wires are crossed.

only other likely causes would be very poor grounding and massive restrictions in the intake/exhaust (aka completely clogged cats)

THANKS! Lol, cats.... not much chance of that ;)

Busted7, could you link me to the fouling procedure? I seem to not have very good search terms?

Thanks everyone!