sputtering/missing when warm
08-05-2009, 12:13 AM
#1
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sputtering/missing when warm So I was driving home today and it started sputtering, at 2k and above idles fine. With no check engine light. I parked it for about 30 min and went for a drive and it ran great for about 5 minutes then started sputtering again. I did a racetronix fuel pump yesterday, and drove it about 30 miles and it seemed fine. Fuel pressure is 42psi with vacuum unplugged from regulator.
I recently did a msd opti, msd coil and wires. Could it be my ICM overheating? How would I test this? THX
I recently did a msd opti, msd coil and wires. Could it be my ICM overheating? How would I test this? THX
08-05-2009, 08:53 AM
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Check your spark plug wires and boots, particularly #5 if you have LTs. If the wire has burned through the insulation it is shorting on your primary causing you to have no spark. Heat increases resistance in wires, and as your engine warms up, heat from the primary heats the core of the wire causing less spark and a short in your ignition system. I had just done wires on my car when I had the exact same symptoms as you describe, and it turned out 1 boot was burned halfway through (#5) so thats $$ down the toilet. If thats not the case, find someone with a good running LT1 and borrow their ICM real fast and see if it helps, its really easy to swap.
08-05-2009, 10:01 PM
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I took it for another drive. let it idle for about 20 min. then ripped **** up..ran great till i swapped a donut and instantly it started sputtering. Im thinking its fuel sloshing around and its running out of gas. I just did the racetronix pump the other day... I have a 3/4 tank of gas.
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08-06-2009, 01:22 AM
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A sensor such as an o2 that is only used when the car is in closed loop mode (I.E. when it is warm) can be the cause of such a problem. Possibly the MAF, but I would check the O2 sensors first.
08-06-2009, 01:36 AM
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Mine had a plug wire grounding out...#5. It was fine till it got warm...started missing after that.
If it was cold and I did a donut it would miss...
WOT it would miss...
I think you have a plug wire grounding out. Wait till its dark...like no light at all...and pop the hood. look for it arcing when it gets warm.
If it was cold and I did a donut it would miss...
WOT it would miss...
I think you have a plug wire grounding out. Wait till its dark...like no light at all...and pop the hood. look for it arcing when it gets warm.
08-06-2009, 10:13 AM
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k i got it figured out. my bad, when i put the pump in, the rubber valve on the bucket fell out but I put it wrong so it was blocking the fuel from filling the bucket. oops
still has a slight miss at idle though, ill check the plugs at night.
still has a slight miss at idle though, ill check the plugs at night.
08-06-2009, 10:26 AM
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Hell you could even do away with that bucket that the actually fuel pump is in. You can mount it directly to the bracket it'self if it becomes an issue again!
