Are the 7427 and 8625 ecm pinouts the same?

[jim_in_dorris]

I want to upgrade my 7747 ecm to the 8625 ecm that I already own to take advantage of the $OD hack. I pulled the male connectors off an old ecm I had, and cut a 3 foot piece of wiring harness out the the 90 astro van I am parting out to build an adapter cable. I have the 7747 to 7427 pinout diagram, so if the 8625 has the same pinouts, I can start soldering. This way, the cable is long enough that I can leave the ecm out of the glove box until I have the tune where I like it. Its going into my 87 oobs 4x4 stepside with a 305/700r4.

[whitelightnin92]

yup! i have and 8625 running with $OD code. the pinouts are identical. same ecm

[jim_in_dorris]

Thanks, I will start soldering then, I appreciate the fast response.

[jim_in_dorris]

Ok, I am resurrecting this thread for a while. I finally got around to printing out the pinout conversion and desk checking everything and ended up with some pinout questions. OLD (747) A7 pin is TCC/Shift Light NEW (427) is E10 or E11 ? Fast had a post in 3rd gen where that was discussed but not answered definitively I have a 700R4. Also I have a question about (OLD) pin B10 park/neutral Switch (NEW) E5 which says range signal C in the GMECM manual. Is that the correct place for this?

[whitelightnin92]

E10 is TCC lockup E11 is PWM i think. use E10. i may be wrong but im 99% shure its E11. not shure about PK/N

[jim_in_dorris]

Thanks, I thought it was E10, but that post confused me a little. I have to re-pin after I build the adaptor because the harness I got has the 12 pin connector like the 747 ECM. How do you get the pins out of the connector?

[drumer919]

A tiny screwdriver or a paper clip works, there is actually a pin removal tool, should be able to get it at radioshack but I have never used or even seen one and I cant imagine something making it that much easier it would be worth buying. About your range/park/neutral question, I dont know for sure but it makes sense, the range sensor/switch is what the pcm uses to know what gear its in.