trickydick

First and foremost, I have a 1990 Pontiac Firebird 6cyl 3.1 MPFI Vin “T”
The story:</B>
I drove my car to an interior upholster place, we talked, I went to leave and started my car and it ran for about 10 seconds then stalled. I did it again…stalled. Again. Same. I tried it one more time and it wouldn’t start at all, just turned over and over. No matter what you did...rev engine it would still stall. The engine smelt like fuel, like it was flooding the engine. Made sense, because you leave it set for a while it’ll start up again and stall. Right?

The troubleshooting: </B>
The first thing I did was check the diagnostic codes….no codes just normal operation. When I towed it home, initially I thought it was a fuel issue. I replaced the fuel filter and blew out the return line with an air chuck. Same problem. I then tested my ignition system. I even replaced the ignition coil and spark plugs. The spark plugs were covered in black soot (carbon). The spark plug wires ohm test was good. I also checked the distributor cap for corrosion. Engine idles perfect. Timing is good. I couldn’t figure it out. I read online it might be my fuel pressure regulator…so I replaced that as well. It still stalled. I was going through my Chiltons book and found that my car has an oil pressure sensor that if not detecting oil pressure it would shut of my fuel. I check the sensor and noticed it was leaking at the wire harness. Even though you could hear the fuel pump turn on, I decided to replace the oil pressure sensor and blew out the oil in the wire harness and tested the wires. Everything tested fine. Sensor was working properly. The car still stalled. Then a friend told me it could be my O2 sensor or fuel pump and I need to test the fuel pressure. I replace the 02 sensor and ran the engine. Nope not it. I bought a fuel tester. The tester was reading 40psi (needs to be within 37 to 45 psi) when ignition is turn in the on position and during startup. Perfect. It never goes down. I don’t know where to look….

Troubleshooting summary:</B>
No codes
Engine Idle good
O2 sensor replaced
Fuel filter replaced
Fuel Pressure Regulator replaced
Oil Pressure Sensor replaced
Spark Plugs replaced
Ignition Coil replaced
Fuel pump pressure 40psi

Engines flooding, spark is good, fuel pump seems fine. What else could it be? Bad fuel? Injectors? ECM?

Please help!!!!

2.8RS

iTrader: (5)

How long does it hold pressure for? It could be your injectors flooding the engine.

trickydick

How should I test the pressure? Turn the key on while the testers hooked up then turn the key off and see how long the pressure holds? Am I supposed to plug the return line?

2.8RS

iTrader: (5)

Leave the gague on the schrader valve after you prime it and see how long it holds. If it goes down right away then your injectors could be leaking. What is your pressure while the motor is running?

xbcrguy182x

Check you MAF or MAP sensor. Its located next to the air filter. Disconnect the plug that goes into it, then start the car and see what happens. If it stays running, then ur maf/mat sensor is no good. I wouldnt recommend leaving the car running w/o it connected tho.

trickydick

Just to note: my fuel pressure tester is plugged inline with the fuel line. My tester didn't come with the schrader valve adapter. (in the attached picture, i put a square around the fuel pressure tester setup)

I checked the fuel pressure during priming. It reach about 44psi. then once the fuel pump turns off, it sit at 40psi and then it takes up to a minute for the fuel pressure to relief to 20/25psi. During idling, the pressure will hold a steady 44psi.

The MAP sensor is attached to my throttlebody correct? In the picture I circled the MAP sensor. I disconnected it. The engine ran for what i thought for a little longer but still stalled and with a fuel smell. Its still flooding.

Xoferif

Nope, that's the TPS (Throttle Position Sensor).

If I remember correctly, the sensor you're looking for is the one in the top-left corner of that picture with the big 'ol green plug running into it.

trickydick

Actually the TPS sensor is right under that connected to the throttle flap. If the top sensor is not the MAP, I found out it the IAC sensor (idle Air control valve) I did try to run the engine withe green plug off (it does have an air line connected to it form the intake manifold); it still stalled on me.


my chiltons says" it is also normal for the fuel pressure to drop slightly when the pump first stops, but it should then hold steady." but my car does not do that, although it is not connecte to the fuel rail...like the directions say. I will have to buy the adapter to fully test it. it also say the pressure should decrease when at idle. which is not the case. can a fuel pump be pumping too much fuel pressure?

trickydick

Could it be the EECS canister? Maybe its full. I thinking this stalling issue has to do with the emmission systems...or injectors.

Xoferif

Yea, I'm gonna blame that one on sleep deprivation.

trickydick

the car is running! can you guess what I replaced to fix it? the ignition module! Man I feel like a dumb ***. The ignition module is located in the distributor. It controlled the timing sequence of the fuel injection to spark

The story:
I went to Advanced Auto Parts to price injectors but the they had none on stock. the guy asked me why I wanted injectors so I told hin the story. He immeiately start rattling off questions and thing to check. The secone one was the ignition module. He told me to bring it in and get it tested. I failed every test! I replaced and BAM. my baby runs like a champ!

Thanks for trying to help me out though.

cutchant

Idle air controll motor is problably sticking not allowing any air into intake plentum this may be why lots of fuel lots of spark but no air rember with injection you dont controll the fuel with your accelrator like the carb you controll air hope thios helps

mercdeking

all your symptoms are exactly what is happening with my car. I got a fuel presure tester from checkers for fuel injected vehicles and it has a shrader connector that fit my connector perfectly. I bled off the fuel pressure by taking off my fuel cap. I would prime it and it would go to 40 psi exactly and would drop off within a minute or 2 to 20-26 psi and it holds at 20.
On idle it holds strong at 42-44psi. But the shop manual I have and the chilton both say that the fuel pressure should drop a bit when at idle.

That's were I got the idea that it could be the fuel pressure regulator unless I just read the shop manual wrong.

I was looking into replacing the fuel pressure regulator with a holey adjustable unit. Can someone explain what the ingition module has to do with my fuel pressure?

From people saying it could be leaky injectors; I have a new "used" and tested set in there from Fuel Injection Connection, I tested the ohms myself to make sure they were near each other and there were no leaks.

I even bought a replacement o2 sensor since the guy at the auto shop I went to said that since I was running rich for so long that I might have killed it. Funny thing is that my car never stalls really bad-no complete cut off and i found out that it was because I was really low on gas later on (fuel gauge is not working), it surges which is what was getting me and if I put the pedal to the metal I get a nasty noise and then my check engine light comes on. Going on a spin right now to make that error come up to test that.

Someone please answer how the ignition module would affect my fuel pressure and thanks!

jstrdn90rs

correct me if I am wrong ,but the ignition module sends a reference pulse to the ECM ,which in turn adjusts fuel injector pulse width ..which will have some affect to fuel pressure.I think that is about as close as you can get to answering your question.I would have to say if you dropped 20 PSI in fuel pressure within a minute after primed, you still have a fuel problem.It shouldnt drop more then 20 PSI in 20 minutes.If you know your regulator is good and your injectors are too ..then a check valve in the fuel pump isnt holding.Easy way to check it .is those two rubber fuel lines along the drivers framerail(in the engine bay).One is inlet and the other is return.Find out which one is inlet,and clamp it down or pull it off and plug it.I use a set of vise grips with pieces of heater hose around the jaws..prime the system and clamp the inlet while watching the fuel gauge.If it drops again 20 PSI in a minute or so its your pump..if it doesnt then prime it again and clamp the return line.If it drops 20PSi in a minute again its in your injectors or regulator or you have a fuel leak somewhere in the system?.

87IROCZ350TPI

Need more info. What kind of noise are you hearing?