Alternate wiring for shift interrupt

[OnagaCat]

I have an '03 350 Mag MPI that had a defective ECU now replaced with an ECU without the shift interrupt codes. Is there a way to wire the shift interrupt switch bypassing the ECU? IIRC the shift interrupt switch is on and off when engaged so would it be as simple as woring into the ignition or fuel pump circuits?

And, yes, I would rather have a new Alpha coded ECU but what I have now was cheaper so i would like to be able to make it work.

 

[Don S]

Re: Alternate wiring for shift interrupt

Is there a way to wire the shift interrupt switch bypassing the ECU?

Not that I am aware of. Ignition and fuel pumps are both controlled by the ECU,

 

[OnagaCat]

Re: Alternate wiring for shift interrupt

Hmm, could I use it to ground the coil?

 

[Bondo]

Re: Alternate wiring for shift interrupt

Hmm, could I use it to ground the coil?

Ayuh,.... Donno,.... It might drive the 'puter Bonkers....

 

[OnagaCat]

Re: Alternate wiring for shift interrupt

Ayuh,.... Donno,.... It might drive the 'puter Bonkers....

Yes, that's my concern.

 

[Don S]

Re: Alternate wiring for shift interrupt

Merc wouldn't have went to all the trouble to make different ECM's for the Bravo and Alpha drives if all it took was grounding the coils for the shift interrupt system.

I remember back a couple of years ago about someone else having problems with lost WOT rpm after making that change. Basically left the engine in SLOW mode all the time. Might try doing a search.

 

[Fun Times]

Re: Alternate wiring for shift interrupt

If anyone could answer a question or modify a PCM such as this, it would be Dustin Whipple of Whipple Superchargers @ (559) 442-1261.

He is able to make some changes to the newer style PCM's, But i'm not sure if this is possible.

http://whipplesuperchargers.com/products.asp?CatID=90&DisplayCat=0

Good luck.

 

[OnagaCat]

Re: Alternate wiring for shift interrupt

Maybe wire it to the ignition key line so it would interrupt there? It would be as if the key was turned off and on quickly and that should cause the stumble needed. I got the ECU from Eric at Simon Motorsports after he determined that my original ECU was bad (Merc actually has a SB covering the bad ECU's. They would sense a false input from the interrupt switch and kill the engine.) and he sent me the current ECU which was not programmed for the Alpha. It's been back to Eric twice now to have the interrupt codes put in and it doesn't work. Nothing against Eric and his companmy as he's been great. I'm just looking for a simpler way to do this without having to send the ECU to California again.

 

[Fun Times]

Re: Alternate wiring for shift interrupt

If eric believes he can get it to work correctly then you would be better off allowing him or someone like him to continue his/their programming magic he/they are usually good at doing.

Eric was the other guy that i almost recommended to you. There are only a few small handful of guys out there that does the marine programming.

Do you still have your old PCM? I believe mercruiser would be able to reprogram it for you as well if you go through a mercruiser dealer.

P.M sent.

 

[OnagaCat]

Re: Alternate wiring for shift interrupt

If eric believes he can get it to work correctly then you would be better off allowing him or someone like him to continue his/their programming magic he/they are usually good at doing.

Eric was the other guy that i almost recommended to you. There are only a few small handful of guys out there that does the marine programming.

Do you still have your old PCM? I believe mercruiser would be able to reprogram it for you as well if you go through a mercruiser dealer.

P.M sent.

We tried re-programming the original PCM and it still had problems so Eric sent me the one I have now. He has my original PCM. I have a n email into Eric to see what we can do now.