I don’t think the pins are being bent but I have not checked. Everything seems to plug in normally. What did you think about the module on the old harness? The original motor was a 454. What do you think is the best solution?

I have 2 MEFI 1 harnesses and no 3's other then what's installed on my boat. Always thought the connectors were different but they may be the same just at different angles.

The module is a knock sensor and is normal but didn't pay a lot of attention to it with current issues.

If it was mine and I spent this much to get it working I would try to change the wiring to make it work. I'm just talking out loud and have not had time to sleep on it and see if there were other options. A guy who I'm thinking might know is Articfriends

For the latest OEM cal using MEFI 1 was 10/ 2 / 1996 and cal checksum was 8E58. So what does your ecm say for that cal checksum when scanned ? Also what fuel injectors do u have installed ? Also the engine serial number will show what is needed for wiring harness and what fuel injectors needs to be installed and the manu date for the engine and so on. .

If I recall the MEFI 3 ecm and that calibration for the 502 came out 5 / 1998.

Not sure what injectors I have. Where is the serial number on block? When the guy put this motor together he did have to flash ecm that’s how I ended up with 2 ECMs. I still have the original harness I can take pictures when I get off work today. I don’t mind re wiring but I would have to have some basically tell me what goes where. Is there anything I can take pictures of to help out please let me know. Thanks for the helps guys.

If the serial number is not above the starter on a plate then its not there. The FPR can be rewired after knowing fully what is going on, but there are some other wires in the 1 going to pins that don't attach in the 3. The Grn/Wht should only come ON with 12V for about 2 seconds then back OFF. If it does that then it can be changed.

That said, the 1 has a few Orange wires (power from MPR) feeding different pins on the J2 side, but the 3 has only one feed (not shown)

Really need to know which harness part number was used with which ECM


https://cimg6.ibsrv.net/gimg/www.off...54437cbf1a.jpg

These are pics of my old harness. The new harness from what I was told is part# 84-861162T1
My injectors are the green 42s
https://cimg8.ibsrv.net/gimg/www.off...98bcc1beb.jpeg
https://cimg9.ibsrv.net/gimg/www.off...f4732156a.jpeg
https://cimg4.ibsrv.net/gimg/www.off...52d305b1d.jpeg
https://cimg7.ibsrv.net/gimg/www.off...184e5995d.jpeg

This is what I would expect to see with a MEFI 1
The FPR has a Black wire which goes to ground


https://cimg8.ibsrv.net/gimg/www.off...d3cc29326d.jpg

Went out to the shop and pulled MEFI 1 harness off the shelf and both of mine looks like your old one. I do believe you have a MEFI 3 harness installed on the motor. Would still be good if we could get a verification of part number

Also my original harness had electronic spark control that what that module I had a picture of. So I am probably not getting any spark either.

If I bought a MEFI 3 ECU for a 454/502 would that solve my problems?

MEFI 1 and 2 used an external spark knock control, the MEFI 3 and 4 the module became part of the ECM

Maybe, if you actually have a 3 harness then you need a 3 ECM to use it, otherwise you need a 1 harness to work with current ECM

Nothing is 100% right now