[weister42]

If you have been tracking my posts I have a hot start problem when my car's been parked for at least half an hour after the engine warms up. First I thought it was my stereo and I ripped it all out, then I had a shop run a cleaning agent to clean my fuel injectors, replaced the fuel pump relay & filter, plugs & wires are 8 months old and the car runs perfect when it's running. I replaced the FPR this weekend and the problem did not improve a bit (60 dollars down the drain:banghead: ). One thing I noticed when I removed the old FPR was a coat of very dark red oily substance under the FPR and probably all around whatever else that's connected to the underside of the FPR, my friend and I couldn't figure out what it is but I don't think it should be there (should be just fuel).

So, I'm confused. I'm wasting my money. WTF???

 

[zonie77]

The suggestion was to buy a vacuum tester and test it before replacing it.

I would test the fuel pressure next.

 

[weister42]

Actually my mechanic told me the FPR is fine...he followed the vaccum test on this forum but I just want to eliminate all the possible faulty parts. Fuel pressure comes out to be 42psi. Again the car drives perfect when it's running.

:bighead:

 

[weister42]

However I do have one question...what are those wires running into the passenger side of the engine compartment? It's a black plastic wire organizer and that's where my power wire for the stereo goes through (wires were the only component I didn't remove when I took everything out). I trimmed the plastic part so the thick wires can go through and it's really close to the factory wires.

 

[eldorado1]

Could you explain in more detail what it's doing?

When you start it, it turns over... does it try to fire? Do you hear a couple puffs? Does it just crank? How long does it take until it does fire up? Does it start up if you let it cool down? (is that the only way it will start?)

What happens when you push the pedal down when you try to start it? Does it start easier? Not effect it at all?

 

[zonie77]

The wires go to the computer, it's behind/below the glove box.

 

[CadillacSTS42005]

I had the same problem with my Trans AM but thats a crossfire lol. (AKA designed by those who had developed the caddy 4 6 8 motor so you kno the set up is shit) i had to replace the ECM worked fine ever since

 

[weister42]

It takes about 3~5 seconds to start when it doesn't want to, starter spins rapidly and everything is normal, car drives perfect when it's on.

My car does start better when I press on the gas pedal (at times when it doesn't start right away), so does this mean I have a fuel leak somewhere?

 

[eldorado1]

So it doesn't even try to fire?

And it only happens when it's hot? No stalling or hesitation or anything when it's running?

 

[zonie77]

I'd hook up a fuel pressure gauge and check it every time I started it. It would be nice to have it sticking out of the hood where you could easily see it.

The check ball in the fuel pump could be leaking and letting the fuel drain back to the tank. I realize this should be true on cold starts also but this is the next step I'd take. If it showed 40+ while no start it would eliminate pump.

 

[coppertop]

I thought the fuel pressure was not to be under 45- 50 PSI? Is that just pre starting the motor? I was ready to change the fuel pump because my car running is at 35 PSI.:suspense:

 

[zonie77]

I said 40 without checking. Don't take that for gospel.


to Weister, check what the pressure should be. If it's even a few pounds low it can give hard start problems.

 

[eldorado1]

I thought the fuel pressure was not to be under 45- 50 PSI? Is that just pre starting the motor? I was ready to change the fuel pump because my car running is at 35 PSI.:suspense:

Fuel pressure should be at least 40psi idling, and it should rise 5psi if you disconnect the vacuum line to the FPR. If that is not the case, you need to investigate and/or replace the fuel filter, FPR, or fuel pump.

 

[El Dobro]

I've had a similar problem with my 98 SLS. The car will not start after approx. 5 min. when hot. It wil start before and after that time period and it doesn't do it all the time. Everything checks out. Now, to play it safe, I depress the throttle slightly to ensure that it starts when I fill up for gas.

 

[weister42]

My fuel pressure is at 42psi so it's normal, I now have to tap the gas pedal halfway down to get the car to start. My car does the long cranks mostly when the engine is warm but sometimes cold. I'm guessing there might be some sort of gas leak that drained the gas out so it takes time for the fuel pump to refill the gas line?

 

[weister42]

So it doesn't even try to fire?

And it only happens when it's hot? No stalling or hesitation or anything when it's running?

The engine tries to start but sometimes it totally fails as if I ran out of gas. Other than that the car runs great on and off highway and even under WOT with five people in the car. Strange huh?

 

[mcowden]

Weister42, it sounds exactly like you have a leaking FPR or a leaking injector, especially if you can put the pedal down and it starts fine. When you have this problem again, run to the tailpipe immediately when it starts and sniff the exhaust. If it smells strongly of gas, you have a leak somewhere, be it the FPR or an injector. It's normal for the exhaust to smell somewhat like gas for a while after starting because the catalyst and O2 sensors have to heat up, but if the gas smell is very distinct and strong, it's got to be a leak into the intake. My money is still on the FPR, despite the test results. Mine was the same way. No visible leak whatsoever but it wouldn't hold a vacuum very long.

 

[Ranger]

If I am not mistaken, holding the pedal half way down does nothing. Holding it to the floor shuts off the injectors to clear a flooded engine. Other than that, the PCM controls the injector pulse width during crank cycle to my understanding.

 

[mcowden]

If I am not mistaken, holding the pedal half way down does nothing. Holding it to the floor shuts off the injectors to clear a flooded engine. Other than that, the PCM controls the injector pulse width during crank cycle to my understanding.

That's my understanding as well. My point is just that opening the throttle will allow more air in there to burn off the extra fuel that has accumulated. If it's loaded with gas, there might not be enough air to burn it and start. Opening the throttle lets in enough air to burn it properly and start. It's just speculation on my part. Am I wrong?

 

[eldorado1]

Depends on how far he holds down the throttle... up to about 50% throttle, it will increase the cranking fuel. Past that threshold, it enters Clear Flood mode, and won't fire the injectors until it is running.

I would put the fuel pressure gauge back on it, and try to duplicate the hard start problem. If the fuel pressure holds steady after you turn the key to run (don't start), but it's still hard to start (after you watch the gauge for a few minutes), then you know it's not the injectors or FPR.