Thread: 1999 GTP Hard to start issues. I am at a loss. Need help!!!!!

Hello all,
I am rather new to the post. I have visited a few times over the years and found all of you to be very educated about the scenarios that come up which helped me fix my issues. I have had this car for 12yrs (has 150k) and have always kept everything in tip top shape, regular maintenance, old changed at 3k, etc.
Need some help because I am at lost. Dealership(s) have no idea


Issue:
car starts up fine when cold or sits overnight. When I drive it for a while and then immediately start again it fires right up. When I drive for 20 mins or longer and then let it sit and try to start I have to crank it for a long while to get it to start and it stutters for few seconds then idles back to normal. Exhaust is really rich fuel smell. At one point blacker then usual smoke came out . Once running it runs great. In the past year had tune up/spark plugs/wires replaced, fuel filter, MAF, fuel pressure regulator, TBI cleaned, idle air control valve replaced, fuel pump assembly. Tried seafoam to help clean as well and still at a loss of what it could be.

I travel a lot for work so took to the dealership while out of town back in Oct and they had off and on for 2 weeks. they did fuel pressure test a dozen times, spark test and gosh knows what else. Dealership was able to reproduce the problem and said believe to be the fuel pump so replaced fuel pump, but still same problem. I don't have a ton of tools to do my own test but can do some. Need help!!!!!!!!!!!!!!!!!

Is the CEL on? Other than that the only other thing that comes to mind is the fuel pump resistor.

I would guess leaking fuel injector. Can you test fuel pressure? Something else you can check (and it's easier), is your throttle body. Make sure it's clean, and the idle air control valve is clean and functional. It sounds to me like you have fuel leaking into a cylinder, or not enough air at start up.

Also for giggles, try to cycle your key on and off a few times. This will make sure you have fuel pressure at start up.

Will look at those items again. No CEL on. It was a few times and replaced MAF and reset and check engine lights have been off since. Throttle body was cleaned few weeks ago. just replaced the idle air control valve. Dealership did fuel pressure test few times when was in shop and said was fuel pump so bought new from autozone. I am confused about fuel pump resistor. I have read it doesn't exist. Is it part of the fuel pump assembly?

Sounds like something is getting heat soaked... I'd look at the icm or crank position sensor.

If you can pull the plugs you can limit it to a cylinderor another system. If one plug looks black or otherwise messed up but theothers are a toasty light brown then it is cylinder specific. Black smoke is fuel vs blue smoke is oil andsteam is coolant. Once you narrow itdown to cylinder or motor you have to figure out why a system or part is notworking correctly. All sensors send avoltage to the computer so you can use a safety pin and a digital multi meterto see what the voltage is and then reference to what it should be (within)before you replace parts.
A rich condition can saturate the cat to the pointwhere the chemical reaction that changes carbon monoxide to water creates somuch heat that it damages the converter as well as the oxygen sensors. At least that’s what we were taught in autotech school but I have not seen a lot of people with this problem so no need to comeunglued about it yet.

it appears to be a bad injector. Hope that solves it.

If you’re on a budget a local junkyard will let you pull an injector for a few dollars. How did you figure out it’s a bad injector? Is it not shutting right?

[QUOTE=Slappyn;950828] If you’re on a budget a local junkyard will let you pull an injector for a few dollars. How did you figure out it’s a bad injector? Is it not shutting right?


took to local garage and he determined it was injector. He said spotted pretty quickly. I wish had time to go to local junkyard but needed it fixed asap. Plus colder then heck the past few weeks in Massachusetts. If was still in AZ would have done it that way. I am not sure why dealership did not see this since they had it off and on for 2 weeks. Since repaired it runs great. no more issues other than $900 in other parts replaced but at least know not much left to replace down the road. starts right up. appear to see a little better gas mileage too according to the control display center.