Car acts funny when hot?

[rob350]

Hi all,

My 85 gn has done this since I got it running. After the car warms up and I got to restart the car, it takes alot of cranking to finally get the car to fire again. When the car is cold, it fires almost instantly when you go to start it. Another problem is when you have the car in park, rev the motor, and let the car go back to normal idle, the rpms will drop down like its going to die, then it will catch and idle as normal. Any ideas what it could be? I haven't hooked the car up to a scanner or anything yet. I also cleaned the IAC sensor but it did no good.

Thanks,

Rob

 

[Jerryl]

Hi all,

My 85 gn has done this since I got it running. After the car warms up and I got to restart the car, it takes alot of cranking to finally get the car to fire again. When the car is cold, it fires almost instantly when you go to start it. Another problem is when you have the car in park, rev the motor, and let the car go back to normal idle, the rpms will drop down like its going to die, then it will catch and idle as normal. Any ideas what it could be? I haven't hooked the car up to a scanner or anything yet. I also cleaned the IAC sensor but it did no good.

You may have multiple issues.
Doe the fuel pump prime when it is hot? (Can you hear it run?)
What is your IAC count? (You really need the scan tool data)
Is your temp sensor working?

 

[GN84Turbo]

Like Jerryl said, it could be may things...but it could be fuel delivery. Get a fuel pressure guage that taps into the fuel line. If fuel pressure drops dramatically after you stop the engine...you probably have bad injectors; theyll leak all of the fuel in the lines into the combustion chamber, wetting the spark plugs, allowing for hard warm start.

Bad MAFs will also make the car run similarly. Some say tapping on a faulty MAF will make the car's idle stumble.

Good luck!