the car is easy to start when cold. but when the car has been running for a while it is a little difficult to start. i have to crank it over for about 3-4 seconds then it starts. what could be the problem?

 

I had the opposite thing happen, when it was cold it would not stay running, but as soon as it warmed up it was fine... The Temp Sensor for the ECM on the front of the Intake was my problem.

$12 in 1999

John

 

My car WON'T start at all once it is warm.
I have to let it cool off for a bout 10-15 minutes before she'll fire up again.
I'm going to replace my coolant temp sensor first and then move on to playing with the crank fuel on the PROM.

I'll figure this one out . . . someday.

 

2 questions, are you running headers??? And secondly, when's the last time you checked out your timing?

Headers cause the starter to heat up more than it would like, so the starter probably doesn't wanna engage when the car is cold.
This problem is amplified if your starter is original(which I'm guessing it is)and is starting to wear out. You don't nesessarily need to have headers to create this problem, however, they seem to kill starters quickly on our cars due to the positioning of the starters right next to the y-pipe connecting flanges.

TIMING: If your timing is advanced, this can cause the car after its run to have trouble starting. Again an old starter will amplify this problem more so, but when your timing is advanced, the engine actually fires on the end of the compression stroke, making it that much harder for the starter to turn the crank. at setting is) 0degrees (where the factory the piston is at TDC when the plug fires, which actually starts much easier with less compression than advancement.

Let me know if any of these could be it, and if not, I'll think of something else.

 

leaking injectors maybe?

 

I was thinking about this, and I had a 90 Riv that had this exact problem, matter of fact when it got hot I had to wiat 10 min for it to cool off before it would start at all. It turned out to be the crank sensor, since we do not have crank sensors on our cars, I would look for things that are important on starting. Because something seems to be changing when the car gets hot and is not needed when the car is running.

John

 

a good place to start looking on a tpi system that starts hard hot is the fuel rail pressure.........GM stock fuel pumps are known for letting the fuel leak back into the tank after shut down......when this happens as the fuel pressure in the rail drops the fuel in the rail starts to boil and at that point the fuel is useless.When you crank the engine over long enough the the fuel pressure builds up and boiling stops and engine starts.There can be other reasons why the fuel pressure drops also...fuel pressure regulator,leaking injectors.A quick test can help pin point if fuel pressure drop is the cause.With engine hot shut off and let sit 15 min....then turn key to the on position(but don't start it)you will hear the fuel pump run for a few seconds then turn off...now turn off key and wait 20 seconds and repeat this without starting the engine until you hear fuel returning to the gas tank(loud sound rumbling in tank) now try starting the car....if it fires right up you have a fuel pressure leak back into the tank after shut down and need to get a pressure guage on the fuel rail with some clamps to isolate the leak back or leak down.