90 lumina wants to stall

[dirtfarmer678]

Hi everyone, looking for a little help
My girlfriend has a 90 Chev Lumina Euro 3.1 that wants to stall out as soon as you give it some gas. It seems to idle alright but as soon as you touch the gas it bogs and stalls out. She has a parts car that ran good but the tranny went out so we have been swaping parts to no avail. It seems to be running very rich and after it stalls it can be difficult to start. when it starts the idle is high: telling me its loading up. We can't get any codes. We have changed the IAC, fuel preasure regulater valve, coil pack, new wires & plugs, temp sensor, replaced vac lines from fuel tank to cannister, cleaned the throttle body, map sensor, cat converter (18 months ago) etc. I'm wondering if it could be the egr. The parts car has a vaccuum module on the egr but this car is controlled by electric solenoids. Is there a way to test the electric egr? Any Suggestions? Is it possible the egr is stuck open & there is too much exhaust being recirculated causing it to stall?
Thanks in advance

[richtazz]

You need to check fuel pressure with a guage at the schrader valve on the fuel rail. It should be 31-34 psi, key on/engine off.

[dirtfarmer678]

Thanks for the reply. I'll see if I can get that checked

[dirtfarmer678]

Borrowed a snap on fuel pressure tester. This is what I got for readings.
Key on engine not running 41lbs
Engine Running 38lbs
Engine shut off 43lb
Is this too high?
The guage was reading 2 lbs without presure so prhaps all readings are two lbs lower.
What to do next? Any thoughts?

[maxwedge]

Pressure apppears too high if the gage is accurate, make sure the return line is not pinched or damaged somewhere along the under body.

[dirtfarmer678]

Haynes repair manual calls for 40 to 47 psi key on not running & at idle 3 - 10psi lower. The mechanic I borrowed the tool from tells me fuel pressure is ok but with the guage possibly being out 2 lbs I'm more confused than ever. I've been under the car & have not seen kinked lines; I've had the fuel tank off recently to replace the vent lines to the charcoal filter & the electric solenoid. Car runs the same before & after the fuel tank drop, so I don't think anything went wrong there. Mechanic thinks its a vaccuum link; so did I originally, I've been over the lines & they look Ok. Unfortunatley, I don't have a vac tester. I ran the car with the line off to the press regulater valve: no fuel came out, pressure went up to 46 psi & car run rough. Not sure if that means anything. Not sure what to make of the discrepency in required psi, but I'm beginning to think I should be looking at the egr. The car had sit for awhile (couple of months) before she purchased it. She tells me its hard on gas, so that makes me think maybe its in the injectors.

Feel free to jump in with any expertise here.

Told the grlfrnd she can't have her car back until its running properly & she's not happy being without wheels so you know how that goes.

[richtazz]

I stand corrected on the fuel pressure. The fuel pressure spec for your car is in fact 40-47 psi. It's odd to me that a Cavalier, with the same engine is only 31-34 psi. With that said, your fuel pressure is within spec. I would check the TPS (Throttle Position Sensor) for any dead spots as it is moved through its range of motion. TPS's can get funky without actually tripping a CEL on OBD-I vehicles.

[maxwedge]

Seconded on the FP, no problem there, I made the same mistake Rich did!. Check for good vacuum to the map also.

[dirtfarmer678]

Thanks for the info. Good to know about the FP; didn't feel like dropping the tank again. Haynes tells me some motors used an adjustable TPS. I'll see what I have tomorrow. Forgot to mention but the check engine soon light comes on after running for 5-10 minutes.
Would a OBD 1 reader tell me anything different than jumping the terminals & reading the engine light. I suspect not but thought I'd ask.
Could TPS malfunction account for black smoke & excessive fuel consumption?

[maxwedge]

Tps would really have to be reading near full throttle for that rich a mixture, and would not correlate with the map sensor and set a code, yes jump a and b in the aldl.

[dirtfarmer678]

Hi Fella's
Been wrenching on the lumins still. Last night I pulled the plenum wanting to check the PCV line. It had a few cracks in it. Auto parts store gave me some 3/8 fuel inj rubber line as a replacement line. Unfortuantley this line cannot make the required curves without collapsing. I suspect this is a specialized molded line?
I also pulled the vac line going to the HVAC and tried the old vac test ie plug one end and suck on the other. It was not holding pressure. It had been repaired before & had a rubber line over the plastic. The rubber line was not sealing properly. Replaced it with better rubber line & it seems to hold pressure. I'm hoping I found my problem. Going to put it back together today if I can find a PCV hose.

[dirtfarmer678]

Car runs much better. No more black exhaust. Car did stall on me twice in traffic yesterday, soits not 100%. As the car had the vac problem for awhile, I'm thinking perhaps the injector's are foul. I've added inj clnr so we'll see how that works out.
I haven't switched up the TPS yet and may do that if performance doesn't improve