Originally Posted by
Paul Woods
Unless you address the check engine light issue first everything else is just white noise.
Locate pin 5 on your 22 pin grey ECU plug, should be a green/white wire, ground it and switch ignition on, your CEL should come on.
If it does not then you have a failed bulb in the dash or wire break, inspect/repair until the CEL works with the grounded pin 5.
Check pin 4 of your V6 ECU 22 pin plug goes to pin 5 on the Mr2 plug, loads of people get that wrong.
If pin 4 is connected to pin 5 and the CEL still doesn't work then your ECU either isn't powering up (no batt or ignition feed perhaps) or your grounds are missing for the ECU. It only needs power and ground to work, so one of those will be missing, go back over my original wiring guide and check your power feeds. Check the ECU grounds are bolted to the ACIS chamber stud and not the rear cam cover.
If you establish the ECU has power, it has its grounds and the CEL is not lit, you could have a bad AFM, I have known a bad one cause the CEL to stay off.
Ignore everything else until you sort that CEL issue and get your ECU powered up.