Regular or Premium gas?
07-31-2011, 02:53 PM
#21
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All I have gotton from running higher octane than 87 is added soot on the back of the boat, I will put some 91 the first tank of the season to add to last years fuel to compensate for octane loss from sitting.
08-02-2011, 07:41 PM
#22
I may have the wrong motor. I think this motor runs slower with 93 then 87. The ecm would run the motor just before detonation. With 93 the ecm would not see any sign of detonation from the knock sensor and would think the knock sensor was bad, and run with reduce timing, thus giving less performance that 87 octane.
08-02-2011, 08:43 PM
#23
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Motor was a 454, not sure what year this was a problem but yes. ECM ran the timing on the verge of detonation. When it thought it should see detonation and did not, it backed the timing way up.
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