hey guys. Was wondering if anyone could give me any advice on an issue im having. My 01 grand prix starts perfectly from a cold start, and ALWAYS runs perfectly once started. But often times lately, once the car is warmed up, ill shut it off then restart it a few minutes later, and it will start right up then die. The tach jumps right up to 1000-1200ish then falls right back down. Sometimes ill press on the accelerator a little to prevent it from dying. Several seconds of cranking is required to start it back up when this happens. . Ive ran 2 bottles of chevron techron in the gas, which has made no difference. I also took the IAC valve out and cleaned it with carb cleaner, and used a screwdriver and shop rag to clean inside the hole it goes in. Ive also tried cleaning the maf, which made no difference, and unplugging the MAF, which made the problem a LOT worse. is there any chance a bad IAC valve could cause this? just acting completely crazy right at start up? Any help would be greatly appreciated! thanks!
warm start troubles
- Thread starter Jakegday
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Do you get a security light at all? Does it keep running if you push that gas like you say? The reason I ask is because many of the cars around that time had issues with the anti theft not working properly which would cause it to start up and stall right away like that. I think it was more popular in the Grand Am but I am pretty sure the Grand Prix was plagued with that problem as well as ignition switches going bad. If it has nothing to do with the security system then my first guess would be coolant temp sensor if I was just guessing and throwing parts at it. Might think it is still cold and flood the engine when you try to start it warm. Seen it many times. They may not trip a CEL they just lie and the car never knows they are not giving the right info.
JHZR2
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Originally Posted By: Jakegday
hey guys. Was wondering if anyone could give me any advice on an issue im having. My 01 grand prix starts perfectly from a cold start, and ALWAYS runs perfectly once started. But often times lately, once the car is warmed up, ill shut it off then restart it a few minutes later, and it will start right up then die. The tach jumps right up to 1000-1200ish then falls right back down. Sometimes ill press on the accelerator a little to prevent it from dying. Several seconds of cranking is required to start it back up when this happens. . Ive ran 2 bottles of chevron techron in the gas, which has made no difference. I also took the IAC valve out and cleaned it with carb cleaner, and used a screwdriver and shop rag to clean inside the hole it goes in. Ive also tried cleaning the maf, which made no difference, and unplugging the MAF, which made the problem a LOT worse. is there any chance a bad IAC valve could cause this? just acting completely crazy right at start up? Any help would be greatly appreciated! thanks!
My 91 BMW 318i does the same thing, summer time only. Never when it is cold out. I always figured it was some sort of volatilization of the gasoline in the injectors. Mine too holds if I keep a tiny bit of throttle, and once stabilized, it will never happen again.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2276343
hey guys. Was wondering if anyone could give me any advice on an issue im having. My 01 grand prix starts perfectly from a cold start, and ALWAYS runs perfectly once started. But often times lately, once the car is warmed up, ill shut it off then restart it a few minutes later, and it will start right up then die. The tach jumps right up to 1000-1200ish then falls right back down. Sometimes ill press on the accelerator a little to prevent it from dying. Several seconds of cranking is required to start it back up when this happens. . Ive ran 2 bottles of chevron techron in the gas, which has made no difference. I also took the IAC valve out and cleaned it with carb cleaner, and used a screwdriver and shop rag to clean inside the hole it goes in. Ive also tried cleaning the maf, which made no difference, and unplugging the MAF, which made the problem a LOT worse. is there any chance a bad IAC valve could cause this? just acting completely crazy right at start up? Any help would be greatly appreciated! thanks!
My 91 BMW 318i does the same thing, summer time only. Never when it is cold out. I always figured it was some sort of volatilization of the gasoline in the injectors. Mine too holds if I keep a tiny bit of throttle, and once stabilized, it will never happen again.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2276343
Fuel pressure regulator could be leaking, causing an overly rich mixture when starting after a hot soak. Do you notice black smoke or lower fuel mileage? If the regulator has a vacuum line, pull it off and see if fuel is in the vacuum line, if so the regulator is bad.
no security light, or anything else to make me think its security system related. regarding the coolant temp sensor, the gauge reads accurately at all times.. No black smoke, and if there has been a difference in gas mileage, i havent noticed it. I dont normally keep track of that, but it hasnt been using an unusually higher amount of gas. Ill check the regulator vacuum line for gas tonight..
Originally Posted By: another Todd
Fuel pressure regulator could be leaking, causing an overly rich mixture when starting after a hot soak. Do you notice black smoke or lower fuel mileage? If the regulator has a vacuum line, pull it off and see if fuel is in the vacuum line, if so the regulator is bad.
well son of a gun. i just went and checked the regulator right after a drive, and there is definitely gas in that vacuum line. thank you for the tip!
Fuel pressure regulator could be leaking, causing an overly rich mixture when starting after a hot soak. Do you notice black smoke or lower fuel mileage? If the regulator has a vacuum line, pull it off and see if fuel is in the vacuum line, if so the regulator is bad.
well son of a gun. i just went and checked the regulator right after a drive, and there is definitely gas in that vacuum line. thank you for the tip!
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Replace the regulator then and your problem will go away (and your mileage will go up). And you are welcome!
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well, i replaced the regulator with one from autozone. the hard start problem went away but it created an entirely different problem. The car would not idle steady in park. it bounced between 500-1500 until after a minute of the bouncing the idle would fall so low that it killed the engine. I put my original regulator back in and went to return the new one. They didnt have a new one in stock so i had to wait until the next day for the new replacement to come in. In that time, i drove with my original regulator, and did not experience the original hard start problem once. And the idle was perfect.
The next day i went to get the new (2nd) regulator from autozone, and it had the same identical idle problem as the first one. I took it back for a refund, and have driving with my original regulator ever since. My car has been starting and running perfectly ever since this ordeal. I should add that i discarded the original o-rings at first, so i had to keep the new ones. So it does have new o-rings right now
So now i cant decide if i should just keep driving with my original regulator, since its working fine now, or go get a replacement from a different store, and risk having the same issue as the autozone one had. what would you do?
The next day i went to get the new (2nd) regulator from autozone, and it had the same identical idle problem as the first one. I took it back for a refund, and have driving with my original regulator ever since. My car has been starting and running perfectly ever since this ordeal. I should add that i discarded the original o-rings at first, so i had to keep the new ones. So it does have new o-rings right now
So now i cant decide if i should just keep driving with my original regulator, since its working fine now, or go get a replacement from a different store, and risk having the same issue as the autozone one had. what would you do?
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For something like the fuel pressure regulator, I'd go with OEM.
Consider also that with the leaking fuel pressure regulator you get some extra volume of fuel into the intake. Your PCM, then, should have learned to reduce the fuel trim - basically open the injectors for a shorter period of time - to get the fuel mixture where it ought to be.
Now when you put on a new non-leaking regulator it loses that extra fuel and runs lean (especially at idle) until it "unlearns". You can probably help it along by disconnecting the battery when you put the regulator on. When you first start it, let it warm up at an idle then drive it around some before you decide if things are better or worse.
Now when you put on a new non-leaking regulator it loses that extra fuel and runs lean (especially at idle) until it "unlearns". You can probably help it along by disconnecting the battery when you put the regulator on. When you first start it, let it warm up at an idle then drive it around some before you decide if things are better or worse.
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Originally Posted By: yonyon
Consider also that with the leaking fuel pressure regulator you get some extra volume of fuel into the intake. Your PCM, then, should have learned to reduce the fuel trim - basically open the injectors for a shorter period of time - to get the fuel mixture where it ought to be.
Now when you put on a new non-leaking regulator it loses that extra fuel and runs lean (especially at idle) until it "unlearns". You can probably help it along by disconnecting the battery when you put the regulator on. When you first start it, let it warm up at an idle then drive it around some before you decide if things are better or worse.
+1
Consider also that with the leaking fuel pressure regulator you get some extra volume of fuel into the intake. Your PCM, then, should have learned to reduce the fuel trim - basically open the injectors for a shorter period of time - to get the fuel mixture where it ought to be.
Now when you put on a new non-leaking regulator it loses that extra fuel and runs lean (especially at idle) until it "unlearns". You can probably help it along by disconnecting the battery when you put the regulator on. When you first start it, let it warm up at an idle then drive it around some before you decide if things are better or worse.
+1
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