Re: engine alarm question for HP500 EFI experts
 

if you have twin mtrs try swaping the ecms

Re: engine alarm question for HP500 EFI experts
 

Talked to Merc Racing Tech Support this morning - they faxed me the discrete sensor test procedure for each of the sensors and wiring check. Problem is that this problem is intermittent, so not just simply a "bad" sensor. Tech Support also recommended swapping ECM's to see if it follows the ECM (if it does, a new one is $$$$, just to make the alarm stop !). He thought maybe more like a rubbed thru wire that is grounding out (he did confirm that the circuits are normally open and close to ground when a problem is present). Next time out, I'll try disconnecting the tan/blue wire on oil pressure switch if I can get to it (without inflicting to many cuts or contorsional maneuvers). Temp is monitored thru the same one that goes to the gauge, per Tech Support, so I think I can rule that one out. If all else fails, I'll disconnect power to that buzzer before I buy a new ECM and use the "redline" feature of the gauges!
Thanks,
Bob :(