1991 3.1 Lumina Weird runing issues

[lilrogue78]

I just bought the car and it starts great then idles for a few seconds perfectly then sputters and dies out and stalls also if i touch the gas pedal it stalls i pressed the button on the fuel rail and it sprays ALOT of fuel so its getting good pressure and plugs look good i also scanned it and no codes so i am dead on ideas so if you guys have ANY ideas please tell me.
Thanks
Dave

[kevinb70]

I think you are on the right track, it sounds like a fuel delivery problem... i would fully check out fuel delivery before moving on to something else

but checking for spray - thats not a good fuel pressure test. you need a fuel pressure gauge to properly test.

check pressure with fuel pressure gauge, PSI should be in the 40s

did you recently run the tank near empty before filling it up? if YES --> replace fuel filter

disconnect vacuum line from the fuel pressure regulator... plug up the vacuum line. see if she starts. just see if she starts and stays running, dont run long like this. FPR is on the fuel rail, just to the front of the throttle body (ok im talking later generation 3.1L but FPR should be on fuel rail, with vacuum line attached) ... if she runs then i think vacuum is dropping the fuel pressure too low, might be bad FPR.

all the while you need to have fuel pressure gauge connected to see how the pressure is during this entire test, and look for any dips in pressure especially when the engine dies. sticking your finger in the shrader valve won't cut it.

also check see if any fuel is getting up in the vacuum line, leaking out of the FPR.


also .. theft deterrent could be cutting the fuel pump off.


also... oil pressure sending unit (sticking out of the block, near the oil filter) controls the fuel pump after startup, safety feature. if this sensor switch is bad, the fuel pump wont run (ie: wreck, engine cuts off, oil pressure drops - this drop shuts off the fuel pump)


I believe the oil pressure sending unit can be bypassed by just grounding the single wire that come out of the sensor. see if this bypass lets it start. if so, immediately stop the engine after that and check for bad pressure switch, bad oil pump, or LOW OIL in crankcase.



plz dont go replacing parts at random. there is a test for just about everything.




a completely clogged cat might cause this as well, and im sure several things i havent mentioned could be causing this too.. but test fuel pressure first.

[lilrogue78]

Okay well i need to get a tester now then i guess but the weird thing is how it runs perfectly then just stalls out or if i touch the gas pedal it just dies ....bah annoying

[kevinb70]

call autozone and the other parts places to see if they have this on Loan-A-Tool, if you dont want to own this incredibly useful troubleshooting tool... ive been seen test driving the lumina around with this gauge popping out of the hood so i can read pressure while driving.

[lilrogue78]

Finally! its fixed ended u being a
a bad map sensor.... go figure didnt even pop a check engine light
tHANKS Guys!
dave