2003 Tahoe starts.... and dies

[brasil]

Friend of mine owns a 2003 Tahoe...5.3 LT and sadly the car makes some strange things

perhaps someone here can show me the right direction ?

O.K. so when he tries to start the engine... SOMETIMES the engeine turns..starts and after 2-3 sec.
dies imediatly. So when he tries to start again... nothing the engine cranks... but will not start. You can smell the gasoline at the exhaust after doing this a couple of times.

But after 20 or 30 tries the engine starts to run... first a little loopy but after 10 -15 sec. everything is fine. also when he shuts off the engine...and make a new start. everything is o.k. but a few days or even weeks later the same Problem occurs again...

Any Ideas ? We checked the Trouble codes... no codes .

Thank you for your help


Greetings Juergen

 

[brasil]

forgot something the car restarts only if he steps in fully on the accelerator pedal and holds it on the floor

also the problem only exists if the car has been parked overnight..i.e with a cold engine.
never had a problem with a warm or hot engine

greetings Juergen

 

[DenaliEd]

When you turn the vehicle over with the accelerator pedal all the way to the floor, it tells the engine that it is flooded, and it shuts off the fuel injectors to help clear the engine of the excess fuel. First thing to check would be the fuel pressure regulator, I don't know if this engine would have one or not, it depends. If it does, it will be on the driver's side (left side) of the intake manifold, it looks like a little disc with a vacuum hose coming out of it. Pull the hose off of it, and if it smells like gas, the regulator is bad. Buy one from a dealer or a GM one, the parts-store ones don't last very long. To remove it you just remove the snap-ring. You can either use a special snap-ring pliers, or in a pinch a screwdriver that fits in the hole will remove it.

If that doesn't work, I'd next look at the injectors, one of them might be sticking open.

 

[rockola1971]

He has a flooded condition BEFORE he tries the old stompy on the accelerator. So he is just getting flooded because the engine isnt starting, not because an injector is flooding a cylinder. So I would be looking at pulses from crank and cam shaft sensors. Or id just just replace the crank position sensor and it will probably fix it. Any codes thrown?

 

[brasil]

There are no codes stored - also when the engine runs there are no stored codes. We used a Auto Xray 4000
to read the codes.
Couldn´t it be the "PAsslock2Antitheft " ? I for my self think that the ignigition has to do with the problem... because there is fuel.. but without a spark ?? The engine will be flooded right ? So how does the Passlock System work ? does it cut the fuel delivery or does it cut the spark ?

in the www I found this : http://newrockies.com/passlock-bypass-2/

perhaps this can resolve the problem ?

Greetings Juergen

 

[DenaliEd]

Usually if it's a security issue it'll start and run, but just for a couple of seconds. And the SECURITY light on the dash will be on.

 

[brasil]

Yes the engine starts and runs a couple of seconds.. then dies. But the security light isn´t on.
The car as I just wrote sometimes runs for 2 or 3 weeks.. without a problem . So you never know when it happens. But it does.
Greetings Juergen

 

[ali saleh]

Check fuel pressure

 

[rockola1971]

When you first turn the key to run position before it gets to engine crank all of the main lights come on and that is a bulb check to see if any of the important ones have bulbs blown. Does your security light come on then? Do all the major lights come on then? If a bulb is burned out then you wont know there is a issue. If all is good there then when the no start condition shows up I would put a fuel pressure gauge on the fuel rail. The PCM has no way to tell if the proper pressure is there or not. If there is enough to get the engine started and running but not enough to properly feed the right amount of fuel then you will get engine lean codes and probably some knock detection too. If there just isnt enough fuel pressure to get the engine running then there wont be any codes stored for that condition because the PCM just has no way to tell.

 

[M1Gunner]

The anti-theft system shuts down the injectors.