Where is the Engine Controller - on the engine, or under the console?

[IDBoating]

I am working on a project on my 24Ve which requires some wiring work under the driver's console. While under there, I noticed that one of Medallion's black boxes is labeled "MEFI" (Marine Electronic Fuel Injection). It has a big connector with LOTS of wires going into it.

I have always thought that the Engine Controller (ECU) comes from the engine manufacturer (in this case, PCM) and is located on the engine itself. The CAN bus provides data to/from the ECU for other things on the boat/car/truck/whatever. But the CAN bus is a three-wire interface... and there are a LOT more than three wires heading into that box under the dash.

I didn't trace out the wires; Tige wrapped them up pretty tight and then covered everything in electrical tape followed by tyraps. Perhaps the wires run between the Medallion box and the dash gauges, for example. But having MEFI on the label makes me wonder. Anyone know?

Thanks!

[dom w. forte]

The ECM is on the motor take a picture of the box you are refering to maybe I can shed some Idea what it is.

[IDBoating]

It's the center, black box surrounded by the dashed white line in this photo:



Note the large grey connector plugged into the top of it.

[dom w. forte]

That looks like the medellion interface to the engine for guage readings,

[IDBoating]

Ah, so the reason for the MEFI reference is to indicate what type of ECU software the box is compatible with. Makes sense. Thanks!

[dom w. forte]

See if there is medellion logo anywhere on the box.

[IDBoating]

Yes, the sticker clearly says so. That's why I said it was a Medallion box. I just didn't know what it did, given the MEFI reference. I think you're correct, it interfaces between the CAN bus and the dash displays.

[kko]

Its called the MMDC.
Medallion's Multiple Module Data Computer - MMDC. The heart of Medallion's CAN based instrumentation system.

[IDBoating]

Between Dom's comments and my guesses that's what I was thinking. Thanks for the confirmation!