Any 502 MPI Experts?
#12
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Not sure about a MEFI 1, but a MEFI 3 will pull a predeterminded amount of timing out when the ECM can't detect the knock sensors (disconnected or connected improperly). It depends on the tune how much gets pulled. You could have retarded your timing a bunch by disconnecting the knock and shot your EGT's through the roof!
#13
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God I Love carb's for engines like these.
Sorry, I know, that's no help.
Sorry, I know, that's no help.
#14
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Agree that the problem is running lean with no spark retard. When I talked with Tyler Crockett he said that 36 psi was probably too low but was a good place to start tuning. The problem was most likely detonation but the question is why did only the # 6 piston melt on each engine and why did the center electrode of the spark plugs melt only on the # 3 cylinders?
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Not sure about a MEFI 1, but a MEFI 3 will pull a predeterminded amount of timing out when the ECM can't detect the knock sensors (disconnected or connected improperly). It depends on the tune how much gets pulled. You could have retarded your timing a bunch by disconnecting the knock and shot your EGT's through the roof!
#17
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the MEFI 1,2,3 all use the same algorithm to retard timing. The observed variables are RPM, Knock Detection, IAT, MAP, ECT. MEFI 4 expands the spark retard by adding 4 additional variable. Then each computer has its own knock recovery table.
I have seen your described failure and it was attributed to detonation caused by either to little timing or to much timing. The heads you use have a great deal to do with timing tables. I am guessing you are still using the 088 heads. They have a pretty narrow ban.
I have seen your described failure and it was attributed to detonation caused by either to little timing or to much timing. The heads you use have a great deal to do with timing tables. I am guessing you are still using the 088 heads. They have a pretty narrow ban.
#18
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Just in case that helps.
Sorry for the carb talk.