Retune time MEFI Burn, AFR

[alldodge]

A few years ago, my 502 MPI, MEFI-1, VST, 415HP and went to a 509 MPI, MEFI-3, cool fuel, 530HP. Since then I've increased oil supply lines, oil cooler, installed oil temp and water pressure gauges. Motor oil pressure has increased along with flow (AN-6 to AN-10 lines), yet the oil temp has exceeded 220 degrees F.

This season I procured MEFI Burn SW and FAST Dual AFR meter and installed yet a larger 2 3/4 x 18 oil cooler. The exhaust tips are a bit black so this is an indication of t running rich. The excess fuel can and does increase heat in the oil/motor.

Took the boat out today and gave it run. Had the laptop displaying Scanner Pro and the AFR running, duct taper to the helm. Find out my AFR is staying close to 12 to 12.5 which is rich. Plan to change the tune and lean it out a bit, also get rid of code 44

 

[DouglasW]

If you are interested, I have written better software than ScannerPro for the MEFI3, but only for scaning and not programming. It is more stable and has more data. You can have it for free. I used to write software like this before I retired a few years ago.
https://www.mediafire.com/#57ejpvimggf51

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[alldodge]

Thanks for the offer, might download. My hesitation is the site wants me to sign up/in before it can be done

 

[alldodge]

Looked thru my vid and recorded the info, so this is the starting point

 

[DouglasW]

Try this link: http://www.mediafire.com/folder/57ejpvimggf51/MEFI3-Scan

 

[alldodge]

That one works, thanks

 

[Strecker25]

Try this link: http://www.mediafire.com/folder/57ejpvimggf51/MEFI3-Scan

Hey man I would love to try this on our motors, I just need to confirm we're MEFI-3's

Would you mind sharing the pinout for making the cable? I have plenty of serial to usb adapters from work (network engineer) so I just need to make the OBD end. Thanks!!

 

[DouglasW]

Sure, here are the instructions:

This ECM uses a GM Opel 10-pin connector:
Connector: https://www.mouser.com/ProductDetail/829-12045808
Pins for connector (2 minimum): https://www.mouser.com/ProductDetail/829-12045773
Cable: https://www.mouser.com/ProductDetail/FTDI/TTL-232R-5V?qs=sGAEpiMZZMtf8aSAtgR7DpPMdam/we00
Cut off 6-pin connector (NOT USB end !) from FTDI cable
Connect black wire to pin A (ground) of the 10-pin “Opel” connector
Connect yellow and orange wires to pin G (data) of the 10-pin “Opel” connector
You do not need all the strain relief and water seals for this connector.


Caution: These instructions are for a specific USB adapter. Your USB adapter cable may use different color wires for the signals going to pin G. Take the cover off the USB end of the cable and note the color of the wires attached to the RXD and TXD terminals. Use them if different than yellow and orange. Many use white and green instead.

Most of the very cheap Chinese-made USB adapters are too wimpy for reliable use and use a counterfeit FTDI chip, so FTDI has changed their drivers to make many of them inoperative. I suggest buying an adapter that has a verified FTDI chip like the one in the link above; but if you already have one, you can certainly try it.