MEFI 1 knock sensor/module behavior
07-07-2022 | 08:39 AM
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MEFI 1 knock sensor/module behavior
Not sure what is normal or abnormal here. 502 Mag MPIs, MEFI 1 ECM
When I did some data logging with Diacom on my Stbd motor, there was 0 knock retard throughout the entire RPM range. No knock retard was recorded at all.
Today I hooked up the port motor, did the same type of run, 6 minutes long, part throttle through WOT. I had up to 9.8 degrees of retard at various times, mostly at part throttle. Seemed to be less at WOT, anywhere from 0 to 4-5 degrees at WOT.
Interestingly, when I compare the Stbd run to the Port run, the MAT (manifold air temp) stays pretty much constant at about 103 the whole run on the Stbd, but on the Port, the MAT spikes up to 140, which seems to coincide with timing being pulled out. Conditions were very similar for the 2 runs, and if anything, the ambient temp was warmer for the Stbd run. Maybe bad MAT sensor?
Is either of these behaviors likely to be correct?
When I did some data logging with Diacom on my Stbd motor, there was 0 knock retard throughout the entire RPM range. No knock retard was recorded at all.
Today I hooked up the port motor, did the same type of run, 6 minutes long, part throttle through WOT. I had up to 9.8 degrees of retard at various times, mostly at part throttle. Seemed to be less at WOT, anywhere from 0 to 4-5 degrees at WOT.
Interestingly, when I compare the Stbd run to the Port run, the MAT (manifold air temp) stays pretty much constant at about 103 the whole run on the Stbd, but on the Port, the MAT spikes up to 140, which seems to coincide with timing being pulled out. Conditions were very similar for the 2 runs, and if anything, the ambient temp was warmer for the Stbd run. Maybe bad MAT sensor?
Is either of these behaviors likely to be correct?
Last edited by DrFeelgood; 07-07-2022 at 10:56 AM.
