383 H/C/I/E knock retard
02-02-2024, 06:20 PM
#21
Well, if some are rich, others are lean and it will average out. More fuel will bring the lean cylinders in line and make the others even richer. Just a guess. Other guess is ex seats leaking on the darker cyl. Reading pligs is hard with modern fuels, they should match tho.
02-02-2024, 07:40 PM
#22
Drifting
Have you done any logging with CL enabled and see if there's a significant difference in fuel trims between the banks? Could help ID problem injectors as well.
02-02-2024, 10:16 PM
#23
I haven't done any. Good suggestion, I'll enable the trims and log. This rain is really making it hard, it's difficult to try and troubleshoot a WOT 3rd gear problem in this weather.
02-02-2024, 10:21 PM
#24
Well, if some are rich, others are lean and it will average out. More fuel will bring the lean cylinders in line and make the others even richer. Just a guess. Other guess is ex seats leaking on the darker cyl. Reading pligs is hard with modern fuels, they should match tho.
Ex seats: valve seals? Should be new, but couldn't hurt to check. I think I'll leakdown test it and see if that gives an indication.
I'm not very experienced reading plugs, but an old timer I work with seems confident that the darkest plug(#3) is running too rich, that #1(semi darkened plug) looks about right, and that the other 6 he doesn't know what to make of. It seems odd that they're so clean, feels like they should have at least some carbon or coloration on them. The plugs in the picture have around 20 miles on them, if that adds any info.
02-03-2024, 12:44 AM
#25
Le Mans Master
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St. Jude Donor '13-'14-'15
Knock Retard and Misfiring are 2 complete separate issues
Both can be explained as FALSE KR and FALSE Misfiring
Very common on engines with cams and thin walled long tube headers
1st you need to deem if in fact you are hearing or feeling a real misfire If NOT then its false Misfiring
Easy fix is to Desensitize the Misfire tables in your tune
2nd Same goes for knock retard IF you do not hear pinging or detonation then again it is FALSE Knock Again easy to fix by desensitizing your KR tables in your tune
Very very common with noisy big cams and LT headers----As the vibrations with a big cam will make the sensors think there is a misfire when in fact there is no misfire just a shacky idling cam
LT headers and cams again the KR is false due to the knock sensors picking up loud noises that are not KR ----- Knock sensors are microphones that hear noises that are deemed NOT STOCK !! and can remove lots of timing for false knock
Both can be explained as FALSE KR and FALSE Misfiring
Very common on engines with cams and thin walled long tube headers
1st you need to deem if in fact you are hearing or feeling a real misfire If NOT then its false Misfiring
Easy fix is to Desensitize the Misfire tables in your tune
2nd Same goes for knock retard IF you do not hear pinging or detonation then again it is FALSE Knock Again easy to fix by desensitizing your KR tables in your tune
Very very common with noisy big cams and LT headers----As the vibrations with a big cam will make the sensors think there is a misfire when in fact there is no misfire just a shacky idling cam
LT headers and cams again the KR is false due to the knock sensors picking up loud noises that are not KR ----- Knock sensors are microphones that hear noises that are deemed NOT STOCK !! and can remove lots of timing for false knock