Pinging/Low Power: Tried much. Bright Ideas?
#1
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Recently bought a 1995 Carrera with 100k. Great shape, great leakdown. But it pings and is definitely down on power. It has one of Steve Weiner's GIAC chips, but even when I swap for a bone stock DME, the problems remain.
-Pulled a spark plug, definitely lean
-Plug wires are in great shape (recently done)
-Distributor belt not broken
-No error codes
-New air filter
Yesterday, I took my first reasonably long drive (~25 mins) in the 45 degree weather. Pinging was much worse (credit the denser air here most likely) - power too. Toward the end of the drive, I could smell fuel (unburned) in the cabin. I should note that the engine runs incredibly smoothly, which prompts me to believe it's not a one-off thing, like one injector or one plug, etc.
I will appreciate any and all suggestions/advice on where to proceed from here. Fuel? MAF? Timing? All of the above?
Thanks in advance.
-Pulled a spark plug, definitely lean
-Plug wires are in great shape (recently done)
-Distributor belt not broken
-No error codes
-New air filter
Yesterday, I took my first reasonably long drive (~25 mins) in the 45 degree weather. Pinging was much worse (credit the denser air here most likely) - power too. Toward the end of the drive, I could smell fuel (unburned) in the cabin. I should note that the engine runs incredibly smoothly, which prompts me to believe it's not a one-off thing, like one injector or one plug, etc.
I will appreciate any and all suggestions/advice on where to proceed from here. Fuel? MAF? Timing? All of the above?
Thanks in advance.
#5
Racer
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Sounds like belt issues to me too. A tooth missing will allow one half to be out of time from spec. Does the engine run the same on either distributor equally well? Unplug one coil wire at a time and test by running it. You don,t need to drive it to tell because it should idle smoothly on either half.. You might also have mixed up the firing order on one set of wires. The engine will run but one side might be igniting one or two cylinders way early.
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#9
Burning Brakes
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I'm surprised you aren't getting a CEL/code. Definitely sounds like an ignition issue, though. Dual-distributor-belt-missing-teeth theory sounds plausible. @Johnsjmc suggestion of mixed up plug wires is good too.
You say the plug wires were changed recently. How recently, and who did it?
You say the plug wires were changed recently. How recently, and who did it?
#10
Rennlist Member
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if all mechanicals are good
1- carbon deposits or
2- cam - chain expansion- timing adjustment slightly off or
3- Oil overfill (some)
Some 993 engines ping like hell when oil tank is over-filled
oil vapor thrown in inlet. miniscule particles of oil in cylinder provoke knock
oil level at midrange on manual gauge is good alternative
1- carbon deposits or
2- cam - chain expansion- timing adjustment slightly off or
3- Oil overfill (some)
Some 993 engines ping like hell when oil tank is over-filled
oil vapor thrown in inlet. miniscule particles of oil in cylinder provoke knock
oil level at midrange on manual gauge is good alternative
#12
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if all mechanicals are good
1- carbon deposits or
2- cam - chain expansion- timing adjustment slightly off or
3- Oil overfill (some)
Some 993 engines ping like hell when oil tank is over-filled
oil vapor thrown in inlet. miniscule particles of oil in cylinder provoke knock
oil level at midrange on manual gauge is good alternative
1- carbon deposits or
2- cam - chain expansion- timing adjustment slightly off or
3- Oil overfill (some)
Some 993 engines ping like hell when oil tank is over-filled
oil vapor thrown in inlet. miniscule particles of oil in cylinder provoke knock
oil level at midrange on manual gauge is good alternative
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I'm surprised you aren't getting a CEL/code. Definitely sounds like an ignition issue, though. Dual-distributor-belt-missing-teeth theory sounds plausible. @Johnsjmc suggestion of mixed up plug wires is good too.
You say the plug wires were changed recently. How recently, and who did it?
You say the plug wires were changed recently. How recently, and who did it?