4.3 EFI cuts off suddenly at over 3000 rpm

[BoatService]

Hello.
I have a problem that stumps me. My engine runs like clockwork on slower speeds, but as soon as i put her onto plane and reach approx 3200 rpm, the engine cuts off as if you would pull a plug out off a socket. No spluttering, just seems like all the electronics fails. Starts up no problem straight afterwards.
Had a tester hooked up and got Fault codes 42- Electronic spark timing fault, and Fault code 43 - electronic spark control fault. On recommendation changed the ESC module - problem persists. On second recommendation changed the Knock sensor - problem persists. What should I do next?
Kr,
Max

 

[makomark]

The codes could have been there a while and may not represent what caused the current issue.

sounds like it is internittent...the EST pickup coils are known to have finite service lives...so you could swap that out...

the other option is to get the factory manual and follow the troubleshooting procedures within.

 

[Dieter]

What is your serial number so we know exactly what you are working on.

 

[BoatService]

Engine nr OL012012

 

[BoatService]

The problem happens every time I bring her up to plane. On lower rpms ok, but as soon as we go up - fail.

 

[makomark]

have you changed the main relay yet?

 

[BoatService]

Have not changed Main relay. Thought; how about the 50 amp Circuit breaker? I have the red push button version.

 

[makomark]

maybe...could be the ignition switch as well...best to stop throwing parts at the issue and actually troubleshoot the problem.

I'd guess that the +12VDC source is dropping out...

 

[BoatService]

have you changed the main relay yet?

Problem solved! Turned out to be the main relay.Mine is mounted next to another relay feeding the trim, and I swapped these two out for trial - everything running perfectly. Sometimes problems can be sorted easy and on the cheap!!!
Thank You.

 

[makomark]

glad that one is behind you...