hard start after run

[Criminal_Mind]

I got a great response from my last post so I'll give it another go about my wife's grand am this time.

My wife has a 97 GAGT with the 3.1L just like mine (except blue), starting the car is easy in the morning, it fires up and runs fine. Sometimes the wife says that it takes a few times to start it but it always does. The problem comes after the car has been brought up to operating temp and then shut off. The car can be drove around but if it is parked and left to sit for about 15 to 30 minutes, it will NOT start again until it has sat and cooled completely back down. By cooled back down I mean that it needs to be sitting for hours before it will start again. It turns over just fine but it just will not "catch" and stay running. I have thought about this until it has made me crazy and can't figure out what the problem is. I can always tell when it has sat for almost long enough to NOT start because when it starts it will sputter and cut out alot until it moves down the road a ways and then will "clear" out and run smoothly. Guys this is driving me crazy. Any idea's on the problem here?

Could it be the fuel pump or maybe plugs and wires? the air filter is new. Could it be the fuel filter doing this? and if it is why would it only give her troubles after it has been running and then shut off for a while? is there a pressure regulator somewhere that may be messing up? I'm lost. please help.

[Coondog]

This is a common symptom of leaking fuel injectors. When the engine is shut off, the fuel injectors are supposed to stay closed and prevent gas from flooding the cylinders. If they are leaking, they dump the fuel remaining in the fuel rail causing flooding.

It sounds like a leaking fuel injector(s). If you have a fuel pressure guage, do a leak down test.

1. Connect the guage and turn on the engine. Bleed all the air from the guage.

2. Turn off the engine. It should hold most of the pressure for quite a long time and it will bleed down over several hours.

or the quickie test.

1. Turn on the engine and let it warm up.

2. Press in the schraeder valve on the fuel rail and drain the gas out. As always with gas, be careful and try to drain it into a cup/rag/ whatever.

3. Let it sit the 15 to 30 minutes.

It should start right up.

[rixGAphx]

Coondog is 100% accurate: Leaking injector(s).
Except when it/they leak, they dump fuel FROM the rail into the intake manifold (which is 'flooding': a mixture so rich that the engine can't fire).

If it were only one injector leaking, then the other cylinders would fire strongly enough for the engine to run and clear the flooding immediately.
My guess is that several are leaking.

Running a bottle or two of name-brand off-the-shelf Fuel Injector cleaner thru the tank according to bottle directions *might* help, but I doubt it.
That stuff is only intended to dissolve the film of varnish that develpos around the injector nozzle, and it is very good at doing so.

Your injectors leak because there are microscopic grains of sand stuck in the injector orifice, preventing the needle from fully seating and thus closing the nozzle.
The micro grains *might* be stuck in some varnish, in which case dissolving the varnish would work.
Most likely, they have actually dug into the metal surface of the orifice and need high pressure to dislodge them.

So, look in the newspaper for a 'Pressurized Fuel Injection Cleaning" special at a reputable place, about $100 for a 6 cyl.
They'll use a solution like the FI cleaner, but apply a lot more pressure to try and blow-out those obstructing micrograins.

It's really weird that the car isn't showing a 'Check Engine' light and codes P0300 thru P0306, Misfire.
Don't let this go too long, or it will damage the front O2 sensor and the cat.

The micrograins prolly got past a dirty fuel filter; should be changed at least every 30k miles.
With all this unburned gas, a change of plugs after this problem is solved wouldn't be a bad idea, either.

Good luck,
-Rick

[Criminal_Mind]

Thanks for the responses guys, know at least i know what the problem is. I'll change the fuel filter and try the injector cleaner and see if it helps at all, if not I might just have the wife abandon the car in favor of another one. It has 197,000 miles on it but it still runs so well. It's almost running like a new car except for this fuel injector problem. I didn't think that it would make it this long but I guess i was wrong about that.

Can't complain really I guess. The 3.1 in my grand am is giving me troubles at 116,000 miles with the LIM and a few other minor things, so I guess 197,000 with nothing but a water pump, a power steering hose, and now the injectors isn't so bad.

As for it putting on a light and giving me a code, it probably is, but the light is probably burnt out.

Thanks again.