Help! There's a unicorn in my engine bay, somewhere
11-28-2011, 07:52 PM
#1
Staging Lane
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Help! There's a unicorn in my engine bay, somewhere Background: 2000 Z28 M6, 176,000mi, ALL maintenence always on schedule or sooner. (stats in sig) Never had anything but Shell or BP 93 octane gas.
Problem: For a week now it occasionally sputters and misses really bad. 2x it completely died while in gear, on the interstate. 1st time it fired back up after a few cranks. 2nd time took bout 20min of cranking and another 5min of violent bucking and surging just to get to 40mph. Then suddenly runs smooth and with full power. Today started acting up til it died and now cant get it to start at all. During all 3 "happenings" the exhaust has a strong fuel odor. The slightest throttle increase during, causes it to stall.
Already ruled out: Fuel and ignition systems components. No visible damage (melted, pinched, scored) to wiring harness or connectors.
Any help at all would be greatly appreciated.
Its what Id imagine a unicorn hunt is like.
Problem: For a week now it occasionally sputters and misses really bad. 2x it completely died while in gear, on the interstate. 1st time it fired back up after a few cranks. 2nd time took bout 20min of cranking and another 5min of violent bucking and surging just to get to 40mph. Then suddenly runs smooth and with full power. Today started acting up til it died and now cant get it to start at all. During all 3 "happenings" the exhaust has a strong fuel odor. The slightest throttle increase during, causes it to stall.
Already ruled out: Fuel and ignition systems components. No visible damage (melted, pinched, scored) to wiring harness or connectors.
Any help at all would be greatly appreciated.
Its what Id imagine a unicorn hunt is like.
11-29-2011, 01:29 PM
#4
On The Tree
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I would start by checking fuel pressure. I know you said fuel/spark are good, but how did you check? I would also check the MAF and clean using a MAF sensor cleaner. Has there been any recent mods done? Headers?
One other thing that pops in my head I have experienced is a faulty IAT sensor in the intake tract. I have seen a few that when bad, read intake temperature is -40* and the PCM was trying to make up for that by dumping loads of fuel.
One other thing that pops in my head I have experienced is a faulty IAT sensor in the intake tract. I have seen a few that when bad, read intake temperature is -40* and the PCM was trying to make up for that by dumping loads of fuel.
11-29-2011, 05:41 PM
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Staging Lane
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1st time I checked fuel psi was spot on, so i dismissed the pump. had it towed to XXX in pensacola, they just chkd it again today and it had nothing. so now it has been traced to the pump, good news is now ill upgrade in prep for the h/c setup.
