Engine surging on cold starts.
08-10-2007, 09:25 AM
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Engine surging on cold starts. I have a 02 Z28 with 30,xxx miles. The only mods are Volant CAI, Granatelli MAF, BBK 85MM TB, and Borla catback.
When I first start it up after the car has been sitting the RPM's will surge between 800 and 1300 or so. Its like I am very lightly tapping the gas then letting off. I was wondering if it was having trouble getting fuel ( only had maybe a gallon or two in the tank ) so I gave it some gas and brought the RPM's to 4K. It made the little popping noises that you normally hear when you shift. I was like WTF so I just let it run a little bit.
Then after it ran for another min or two, it went to a steady idle of around 900 or 1000. It also didn't do the little pop noises when I hit the gas ( although it does them most of the time when I shift at more than 4K rpm in low gears )
Is this the best place to post this or should it be in the Engine section?
When I first start it up after the car has been sitting the RPM's will surge between 800 and 1300 or so. Its like I am very lightly tapping the gas then letting off. I was wondering if it was having trouble getting fuel ( only had maybe a gallon or two in the tank ) so I gave it some gas and brought the RPM's to 4K. It made the little popping noises that you normally hear when you shift. I was like WTF so I just let it run a little bit.
Then after it ran for another min or two, it went to a steady idle of around 900 or 1000. It also didn't do the little pop noises when I hit the gas ( although it does them most of the time when I shift at more than 4K rpm in low gears )
Is this the best place to post this or should it be in the Engine section?
08-10-2007, 10:30 AM
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I don't have a lid, the car came with a volant CAI kit. Here is a pic:
http://www.redlineperformanceenginee...om/volant1.jpg
http://www.redlineperformanceenginee...om/volant1.jpg
08-10-2007, 01:59 PM
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Did you make any recent changes to the car just before this issue started?
PS. Moving to General Maintenance & Repairs....
PS. Moving to General Maintenance & Repairs....
08-10-2007, 02:28 PM
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Originally Posted by plainred02Z
I have a 02 Z28 with 30,xxx miles. The only mods are Volant CAI, Granatelli MAF, BBK 85MM TB, and Borla catback.
When I first start it up after the car has been sitting the RPM's will surge between 800 and 1300 or so. Its like I am very lightly tapping the gas then letting off. I was wondering if it was having trouble getting fuel ( only had maybe a gallon or two in the tank ) so I gave it some gas and brought the RPM's to 4K. It made the little popping noises that you normally hear when you shift. I was like WTF so I just let it run a little bit.
Then after it ran for another min or two, it went to a steady idle of around 900 or 1000. It also didn't do the little pop noises when I hit the gas ( although it does them most of the time when I shift at more than 4K rpm in low gears )
Is this the best place to post this or should it be in the Engine section?
When I first start it up after the car has been sitting the RPM's will surge between 800 and 1300 or so. Its like I am very lightly tapping the gas then letting off. I was wondering if it was having trouble getting fuel ( only had maybe a gallon or two in the tank ) so I gave it some gas and brought the RPM's to 4K. It made the little popping noises that you normally hear when you shift. I was like WTF so I just let it run a little bit.
Then after it ran for another min or two, it went to a steady idle of around 900 or 1000. It also didn't do the little pop noises when I hit the gas ( although it does them most of the time when I shift at more than 4K rpm in low gears )
Is this the best place to post this or should it be in the Engine section?
Mine did that and I got the exact same surging on cold start up as you describe, than it would smooth out and idle normal.....and it would drive around 100% normal. You cannot tell the engine/PCM is in SD tune.
Mine was in SD tune and I could go drive around NORMALLY and the engine performed perfect.....with BOTH the MAF and TPS unplugged.
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08-10-2007, 03:18 PM
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why would my PCM be in SD tune? Don't you have to go to a tuner and pay $500 bucks for that? I doubt the person who used to own this car did that as it doesn't have any big mods that warrant a tune. Also, why would he leave the MAF on there if its got a SD tune done?
08-10-2007, 05:22 PM
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Originally Posted by plainred02Z
Don't you have to go to a tuner and pay $500 bucks for that?
If a part like the TPS or MAF fail, the PCM will automatically default to a SD tune. Mine did just that, the PCM is supposed to do that so you can still drive the car. And it drives perfectly. Mine did for over a year before I realized it.
Just do the tests I described and see if it happens. Have a buddy sit in the drivers seat so he can turn the engine off in case it revs up a bit when you do it...just in case.
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