runs fine, then acts like bad gas, backfires chugs. dies throws check engine light
02-11-2008, 04:20 PM
#16
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Join Date: Mar 1999
Location: Moore, OK
Posts: 584
He came over today, I put my old opti harness on it and the low res code went away. Has a 36 and a 42, I can clear the codes start the car and it pops and backfires, the check engine light comes on and it clears up, runs TOTALLY like normal. Never seen anything like it.
When the check engine light comes on, does it use it's own high res pulse in a backup table in the ecm?
David
When the check engine light comes on, does it use it's own high res pulse in a backup table in the ecm?
David
It runs off the low resolution pulse. The high resolution pulse is for fine tuning of spark timing. So the car will run fine with a code 36 (hi res failure), but a 16 (lo res failure) will shut the damn thing down.
whats a 42?
02-11-2008, 04:38 PM
#17
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Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,825
DTC 42 = Ignition Control (IC) circuit (shorted or grounded circuit)
Can be many things, including the IC Module, Opti, PCM and/or related wiring. There's a good logic diagram in the factory manual for working your way through the possibilities.
Can be many things, including the IC Module, Opti, PCM and/or related wiring. There's a good logic diagram in the factory manual for working your way through the possibilities.
02-11-2008, 06:06 PM
#18
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Join Date: Jan 2006
Location: Fairhope AL
Posts: 487
icm swapped yesterday.. no changes
Fast fat boy..Hell of a guy, alot of people try to help out on here...but he went WAY out of the way to help me. hats off, and a promise to him on here..need anything call dude..I'm on my way
Fast fat boy..Hell of a guy, alot of people try to help out on here...but he went WAY out of the way to help me. hats off, and a promise to him on here..need anything call dude..I'm on my way
02-14-2008, 04:58 PM
#19
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Join Date: Sep 2004
Posts: 0
sounds like it's jumping back to open loop
Do we assume that you have an 96 or up based on the pics in your signature and it's converted to OBDI since you are throwing 42's and the like?
When I had a burnt O2 harness, it would run like crap then jump into open loop for a moment and run fine.
Don't see a problem with the IC signal causing it to do anything that would resemble that.
When I had a burnt O2 harness, it would run like crap then jump into open loop for a moment and run fine.
Don't see a problem with the IC signal causing it to do anything that would resemble that.
02-14-2008, 05:06 PM
#20
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Join Date: Jan 2006
Location: Fairhope AL
Posts: 487
converted to a 96? Hmm not sure how that happened. LOL
its a 94 lt1 auto. Mods are numerous small mods. fastfatboy helped. Think we narrowed it down to Opti. Not a problem. tax refund on the way. Swapped ICM on sunday, no changes. Swapped O2's Monday didn't solve it. Swapped harness to Opti, no solving. I don't mind buying parts, just don't like throwing money at it for no reason. Its nice to know the why's and hows of the car and its sensors. I figure 162,000 and stock opti its time. Who knows. maybe it will get faster....(I doubt it thou)
its a 94 lt1 auto. Mods are numerous small mods. fastfatboy helped. Think we narrowed it down to Opti. Not a problem. tax refund on the way. Swapped ICM on sunday, no changes. Swapped O2's Monday didn't solve it. Swapped harness to Opti, no solving. I don't mind buying parts, just don't like throwing money at it for no reason. Its nice to know the why's and hows of the car and its sensors. I figure 162,000 and stock opti its time. Who knows. maybe it will get faster....(I doubt it thou)
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