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IROCDave
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Joined: 16 Jan 2010
Posts: 957
Location: Snohomish WA
1987 Chevrolet Camaro IROC-Z
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 Posted: Fri Sep 24, 2010 7:25 pm Post subject: Code 43, no CEL..... |
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As most of you know I installed a set of AFR heads and a much larger cam this past spring. The last settup ran really lean and this one is worse. It ran OK for the 3 months following the new settup, decent mid range tourqe and upper RPM HP. A couple of months ago it started to miss at mid throttle input, especially while in upper gears. It now stutters hard while lugging in any gear. When my scanner connects to the ECM it shows a code 43, but it says the ECM cannot control igniton timing, bad ignition control module or something along that line. Research on TGO says code 43 is associated with the knock sensor.
I pulled the car out of the garage tonight and un hooked the battery to clear the codes. After 10 minutes I reconnected the battery and started it. No codes. I then connected a dial back timing light to verify the timing settings /readings that the ECM is seeing. At idle the ECM is showing 23 degrees, the timing light showed 18. At 3K rpm the ECM was showing 39.5 and the dial back light was showing 31 degrees.
Intial timing is set at 6 DBTD. It runs like the timing is retarded and my timing light is telling me this is true. Do you think my timing light is off that far or is there something I am missing?
Why doesnt my indepedent timing light not agree with the scanner reading of what the ECM is seeing? With the way the car is performing it feels like it is missing timing, but I havent changed the intitial timing in months 
Any idea? |
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aaron_sK
Member
Joined: 23 Jan 2006
Posts: 8834
Location: Back in beautiful Tacompton
1987 Chevrolet Camaro IROC-Z
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| Posted: Fri Sep 24, 2010 7:36 pm Post subject: |
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When you burned the chip, did you change the spark reference? You need to verify that it is set at 6* before, or the ECM will be consistently off.
Can you datalog? If so, is the ECM actively seeing knock counts?
FWIW, if you are running lean, this may be a symptom rather than a cause. |
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IROCDave
Member
Joined: 16 Jan 2010
Posts: 957
Location: Snohomish WA
1987 Chevrolet Camaro IROC-Z
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| Posted: Sat Sep 25, 2010 7:03 pm Post subject: |
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| aaron_sK wrote: | When you burned the chip, did you change the spark reference? You need to verify that it is set at 6* before, or the ECM will be consistently off.
Can you datalog? If so, is the ECM actively seeing knock counts?
FWIW, if you are running lean, this may be a symptom rather than a cause. |
Ed Wright burned the chip for the old settup ten years ago. It ran lean ( over 15 - 1 @ WOT on a wheel dyno with a WB02 stuck in the exhaust tip) 10 years ago. This was at The Carb Connection in Kirkland. The CC owner was amazed that it wasnt pinging / knocking. I had Trick 102 in the tank at the time and the CR was around 9.4 - 1.
With the new heads ( smaller combustion chambers and thinner head gasket, MLS) the CR is at 10 to1. It pinged badley at WOT with the base timing set at 10 degress BTD at the track. I backed it off and still heard the pinging but didnt see KR on the scanner until it stopped reading 1/2 way through the pass. I pulled all of the plugs a couple of weeks ago and they all looked the same, almost pink in color, no spots.
The stumble is more recent and seems to be getting worse. After clearing the codes yesterday throttle inputs while sitting still seem snappier xcompared to 10 minutes before. Didnt drive it though.
Guess I need to verify that my timing light is accurate then go from there? |
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iansane
Member
Joined: 16 Jan 2004
Posts: 5742
Location: Bothell
1991 Pontiac Trans Am
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| Posted: Sat Sep 25, 2010 9:07 pm Post subject: |
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You want to borrow my timing light?
Fuel pressure okay? What's it set at?
_________________
| Quote: | | Sometimes I actually think I'm slightly retarded in the mouth. |
Last edited by iansane on Sun Sep 26, 2010 9:34 am; edited 1 time in total |
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IROCDave
Member
Joined: 16 Jan 2010
Posts: 957
Location: Snohomish WA
1987 Chevrolet Camaro IROC-Z
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| Posted: Sun Sep 26, 2010 9:14 am Post subject: |
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I had it set at 65 PSI to see if it would help out with the pinging. It is now set at 48 PSI.
Do you have a dial back light? If yes I would like to borrow it. |
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