What are the facts about 280z ECU compatibility and differences

[Patcon]

It's good to know they are irrelevant, though.

[cclxxxz]

so i can buy a 1976 ecu for my 1978 280z?

[Av8ferg]

so i can buy a 1976 ecu for my 1978 280z?

Captain Obvious can possible answer this best but my understanding is you should be good to go.


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[Zed Head]

Nissan's own ECU document says that the Federal models use the same ECU for the manual transmission cars, even some auto cars.  The document is in the Downloads area.

[Captain Obvious]

What he said. Looking at the documentation, it appears that 77 and 78 share the same Nissan part numbers, but 76 is different. I do know that they started putting the altitude compensator device (module under the dash above the driver's knees) in 77. So that would definitely be a difference between the CA parts for 77 and 78, but I don't know why the non-CA parts would be different as well.

Also interesting that the JECS numbers are the same for 76 through 78.

Anyway... Sorry. but I honestly don't know what all the differences are, so unless someone else does, the safest thing would be to get one from 77 or 78.

[Zed Head]

9 minutes ago, Captain Obvious said:

What he said. Looking at the documentation, it appears that 77 and 78 share the same Nissan part numbers, but 76 is different.

Different for automatic transmissions, same for manual.  The chart is manual, M/T, on the left, auto, A/T, right.

I think any differences are tiny and probably tied to emissions.  I've tried 75, 76, and 78 in my car and they all worked the same.

Edited February 27, 2019 by Zed Head

[Dave WM]

I was fooling about testing my spare ECU's. On is on my 76 spare engine, that spare ECU works fine. its a A11 then all 000's, my other spare is a A11 600 then all zeros, it does not work. I tried it in my car as well again does not work. My Car is a 75 cali it also has a A11-000 as the working unit, the spare engine was a 76 non cali.

so the 600 does not work in my 75 car or my 76 spare engine on the test stand.  both my A11-000 work.

 

I tried the A11 600 again on the spare and was able to get it to run IF I deflected the AFM vane manually A LOT like 20 degrees. So that clears its functioning to at least ground out the injectors but not much more. I should have listened to see if they were cycling, for all I know it may have been just a constant "ON" . I only managed to get it to idle, it was too hard to mess with the throttle and keep fingering the AFM vane in an attempt to keep it running. I think I will try it again and see if they are indeed duty cycling at all.

 

[Zed Head]

I tried ECU's from 75 to 78 on my 76 and they all worked.  Might be that there's something wrong with that A11...000 ECU.  I was lucky enough to have my car when lots of spare ECU's were floating around from a local guy, and I had a 76 original and a 78 parts car.  All Federal models.  I always tried spare parts in my car to be sure that they had value.

[Dave WM]

I suspect its a defect as well, why I want to see if its really duty cycling or not when I move the AFM manually. good to know they all worked. I had read up that the 600 vs 000 should make no diff. I was starting to think maybe I had one that needed an O2 Voltage... all the pins were soldered to pads on the pcb from the 36 pin connector.

Edited February 10, 2020 by Dave WM

[Av8ferg]

This ECU topic is an interesting subject, I have three of them. I found a place in Memphis Tennessee while I was working that is an ECU repair shop I have thought about taking one of mine down there to have them look at it and see if they have the proper documentation and equipment to test. Even though it’s working properly I wonder if it’s really exactly like it should be since these things are so old.
Dave I think I confirmed your findings as well because one of my ECUs was the automatic transmission 600 series and if I remember correctly my car would not run with it in there and that was one of the problems that the previous owner could not figure out.


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[wheee!]

One of mine. It has newer components but was in my 9/75 280Z

 

 

[Zed Head]

As far as the main inputs and outputs what would be different, to cause one to not work in any certain car.  The fuel curve might be different, to work better with an automatic versus a manual, but the Pin 1 signal and the injector opening and closing should not be affected enough to cause major problems.  Certainly not starting problems.  These things aren't even computers, as we know them today.  They're just parts in an automated system.  Signals and measurements in, control signals out.  The ECU can't tell what car it's in, they all look the same to it.

The wiring diagrams for the EFI system don't even have any of the typical "auto" versus manual dotted lines, like the full car diagrams do.

And. if you look at the chart in the first post, NMC and JECS don't even distinguish between them in the same way.  JECS uses the same number for all of the MT cars, except for 75.  NMC switches after 76.  No rhyme, no reason.

Also, didn't know this myself, there is no Federal 1975 car, apparently.  I don't think that's right but the chart has nothing listed.  Do all 75's have catalytic converters and EGR?

Edited February 11, 2020 by Zed Head