pcmhacking.net

Most GM Performance and Marine engines use MEFI 1-6 over the years, but I am mostly looking for something to read Mefi 3 and Mefi 4/4a/4b. I am looking for a solution to read/write the controller which requires a password to read but not write, and the control definitions for TunerPro and ScannerPro. It is my understanding that getting data from the Mefi 3 and 4 over serial is pretty simple. And they even support some live data over CAN. However Mefi 5 and newer requires some DIACom trickery, though that isn't very important to me. Mercury Marine went to the MPC555 before Mefi 5, and I know I can do that with a BDM 100, though I haven't yet.

MEFIBurn seems to be the only somewhat reasonable option right now, with the standard level control definitions and cable (which I think I can make an OBDII to MEFI adapter, from what I understand) right around $600USD. I typically would just grab it up, but I would have to call him for file passwords and he would not give me a clear answer how many he would allow. I am not a shop, but I tinker a lot on these boat engines and so do my friends. So being up to his discretion was not something I feel comfortable with. I have an understanding of most of this beyond the average Joe, and while I have some IT background, this is beyond me. I have seen a few people manage to make this work with TunerPro by simply writing .bin files with no password, and starting over. I would prefer to read, in case the Mefi has been previously modified but locked. I am willing to compensate someone for a permanent solution whatever that may be, if you think you may be able to help please let me know.

Thank you.

Edit; I have read the ALDL should be the same as the LT1.

http://www.michaelstractors.com/forum/t ... PIC_ID=199

Data Link Connector:

The Mercruiser wiring harness contains the "Data Link Connector". This is a 10 pin Delphi (Packard) "Metri-Pack" 150 series connector which connects to Diagnostic Test Tools.

The connector pins are as follows:
A - Ground
B - Diagnostic Enable
E - MIL (Malfunction Indicator Lamp) status
F - Battery
G - Serial Data 8192 Baud

From a quick skim of the documents, yes it sounds like its aldl protocol same as most of the stuff on this site. Very common on gm approx 1989 to 1999 computers and still present on aussie commodores as a vehicle data bus up to approx 2006.

Scannerpro was the alpha version of tunerpro 5's logging aka scanning engine. It was discontinued and moved in to core tuner pro some years ago. The definition format changed but can be imported and usually needs only a slight change to the connection macro to work.

The mefi adds say it can be used on ls engines, so presumably you could also go the other way and put a gm '0411 car pcm and loom on your mercruiser and then have a lot more better car tuning options.