Wow! I think I am using the wrong harness!!
 

Please correct me if I'm wrong, bc I have seen quite a few build threads and some have the grey and some have the yellow plugs.

I have a 90 7mgte and I am currently wiring the motor (on engine stand) to see if it is going to work.

I have a 89+ 7mgte m/t ecu. Both the harness and the ecu have the yellow plugs.

Am I using the correct one?

I also have a harness that has Grey plugs, can someone tell me the difference and why the one with Grey plugs does not go into my ecu.

Thanks

Generally, you want to keep the same year with the same year AND same model with the same model.

If your car is pre89 you'll be wanting the pre89 harness (and some of the pre89 electronics ----- this is the YELLOW plug series), pre89 ECU and pre89 motor mounts. And if the car is 89+ then you'll want the 89+ parts.

EDIT: If the plug colors are the same but the connectors are different then it isn't for the same model.

Ok thanks cre-

I am down to the nitty gritty!!

The car itsrlf is an 86.5 NA. I have a 89+ 7mgte in it now. The wiring I have has the "Yellow" plugs, as well as the ECU. Now, I cannot find almost any of the plugs/connectors to the (89+ motor) thermostat housing senors.

My question is;

Do I need the grey plug harness and ECU because my motor is a 89+ 7mgte or do I need the yellow plug harness and ECU because my "car" is a pre89 model? I am sorry if this sounds confusing, but, I'm confused!!

One more thing, I am going to be using aftermarket oil pressure, temp, and boost gauges. I dont know if that will help in me using a certain harness but oh well.

NOTE: I tried to turn the key on to see if I was even going to be getting any juice/power out of it and..zero. I dont know if I am missing anything as far as ground or a power wire somewhere but I dont have any power to anything. I currently have the yellow plug harness and ecu hooked up. Any tips??

Thanks a lot