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-   -   502 MPI Issues (https://www.offshoreonly.com/forums/donzi/381075-502-mpi-issues.html)

Guamache 11-19-2023 12:18 PM


Originally Posted by F-2 Speedy (Post 4885305)
When you but it back together did you put the ecu in base timing mode to adjust the timing ?

Base timing mode?? ...I did not, but I took the boat to this guy`s shop, he said he set it in time, replaced the IAC, but did not fix the issue, he thought he did

Guamache 11-19-2023 12:21 PM


Originally Posted by AllDodge (Post 4885313)
Did they use your old cam or a new one?

Your old one good then this is one less thing to think about

If it was new cam or one from another motor need to know if it was same profile

Are you sure it's a 502 block and not a 454, (checked numbers)?

Just spit balling

Hi there, yes I made sure it is a 502 block, guys at the machine shop also made sure it is a 502. I installed the same cam. The issue came on before I took the engine apart, ice related or not, I dont know. Thanks

Guamache 11-19-2023 12:22 PM


Originally Posted by sonicss42 (Post 4885293)
Might want to check your wallet, things might get expensive. :party-smiley-004:

haha tell me about it!

F-2 Speedy 11-19-2023 12:27 PM


Originally Posted by Guamache (Post 4885344)
Base timing mode?? ...I did not, but I took the boat to this guy`s shop, he said he set it in time, replaced the IAC, but did not fix the issue, he thought he did

That engine ( mefi 3 ecm ) needs to be set in base timing mode with ether a hand held scanner or lap top with software in order to set the timing, you need to follow up with your guy, if he's not a marine guy he might not know this.

AllDodge 11-19-2023 12:53 PM

All MEFI s can be placed in base timing more with a paper clip placed on the DLC connector

smokediver 11-29-2023 04:11 PM

Check the intake. If it was a saltwater engine.


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