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2003 mercruiser 350 mpi detonation

ragolawracing

New member
"Anyone have any idea where to

"Anyone have any idea where to start on this problem? 2003 Mercruiser Mpi 350 in a Ski Centurion. Motor has about 70 hours and has run flawlessly until last week. Engine began to ping immediately at all rpm both with and without load. I changed fuel thinking that I had got some bad gas. This tank was new but still changed it. This was not the first time up this summer and prior there was no ping. Next week same thing with gas from different station, same octane as I have always used (super) and the gas worked fine in the ski's and vehicles. No load or load and the same thing. Detonation everywhere. If rev'd out of the water it still pings. Nothing has been changed and timing is electronic and has not been touched. It sounds like the ECM may need flashed and lost the programming on the unit. Any ideas? Where is the programming harness for troubleshooting etc.?"
 
"Your engine may be in the &#3

"Your engine may be in the "limp in mode" due to a computer command that sensed a system failure.

This old backyard trick sometimes works on cars. Can't hurt to try. Before paying to get it scanned by a dealer, disconnect the ground cable from the battery and recharge the battery to maximum charge. Reconnect and test on ear muffs."
 
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