What Marine EFI systems are engine builders using with high overlap cams? Any of these have mass airflow sensors?

Michael

Micheal,
I use a MEFI and only a MEFI. I love the computer and have never had a problem with one. Not the most user friendly piece in the world, but well worth the learning curve.
There are several systems out there using a mass airflow, but I don't know that you could make it work in a boat.Don't know of anyone that has. Eddie.

I'm sorry, but I am not familiear with MEFI. Do you have their website address?

Thanks!

General Motors

M Marine
E Electronic
F Fuel
I Injection


That is what came on my 500 EFI. When I changed my cam I had to get mine reprogramed. It was running WAY TOO RICH.

The MEFI computer is what Merc used for about ten years until the recent introduction of the pcm555. I think it is the best computer to use in a boat. It is the only one that has extensive knock protection. Other systems have knock protection, but it is crude compared to the MEFI. Not many people use it because it is not user friendly, because it never was meant to be. There are only a handful of people that have the ability to reprogram a MEFI computer.
Systems like Fast, EFI technologies, Accel DFI, Holley Commander, Big stuff etc. are much more user friendly for the first timer. They are also much easier to get up and running when starting from scratch. While these are all good systems, I still think the MEFI is the best. I'm sure someone will argue with me, but that is my opinion and I'll keep using them until someone comes up with something better. Eddie

If you go onto GM Power Train's web site, they now are offering the Marine EFI version 5. I called GM about getting the software a year or so ago. I got a live guy on the phone and was told that the programming software is avalible to engine builders. He said an agreement must be signed that essentially states that you will only use the software for off road use and will not program any emission controlled engines. I came to grips, that it was too complicated to do just a couple of engines and sent my computers off.

Links

http://www.gm.com/automotive/gmpower...rine/index.htm

http://www.gm.com/automotive/gmpower...ne_engines.pdf

I was over at the Corvette forum site, and someone there said you had to put in a 50 unit order to GM for MEFI controllers before they would give you the programming software. Is that true? I don't know too many builders who would be able to buy that many.

Also can the MEFI unit run in Alpha-N (throttle position) mode for big cams with erratic idle vacuum?

Michael