Hi guys I need some help here, I have a 77 280z and I just recently noticed that not all of the pins on my ecu match the ports on the harness connector, the part number on the ecu is A11-601 but why am I missing connections?

Edited April 7, 201312 yr by bryand2
adding pics

Assuming the car is an auto trans, you're fine.

The reason the contacts don't match up perfectly is that there are a couple locations that aren't used when the car is being driven, but are used for diagnostic purposes.

On the harness side for example... Pins 20 and 21 on the wiring harness don't make any connection to the ECU, but can be used to verify the functionality of the fuel pump signal and cold start system respectively.

And on the ECU side for example... Pins 11 and 26 are test output locations for the injector signals. They aren't used for anything when the ECU is in the car, but they could be probed to see what the injector drive signals are doing.

I don't see anything wrong with what you have there.

I forgot to mention that I also see that you have the pin 12 altitude compensator switch connection (which makes perfect sense since you're in CA). The non-CA cars (like mine) do not have a contact in the number 12 position on the harness side.

No, my car is a 4 speed

The A11-601-000 ECU is for 77-78 auto trans.

If you've got a manual trans, you should be running a A11-600-000. I don't know what the difference is and I'm not sure if it's really a problem, but that's what the documentation says.

So, was your car originally an auto, or do you think the ECU was replaced with the wrong one at some point in the past?