I did an experiment with a spare ECU I had laying about. both ECU's say the same thing "Do not use on 1978 or Earlier models blah blah blah" But the stickers are different along with the tin case.

I decided to change mine out with the spare. and found that the spare made the engine idle and rev so much more smoothly then my stock one. which at idle made stumbling sounds every so often and wasn't so smooth. Not like a miss fire but a bad injector or something

The only flaw with the spare ECU is that if the TPS is hooked up it will not go past 3K rpm AT FULL THROTTLE. If I dont push it down all the way it will go all the way to 6k. if I unhook the TPS everything is fine. And I checked the TPS it is working properly.

So I'm wondering if there's a difference between the 2 ECUs

SPARE ECU #
Blue sticker, A11-602 420

STOCK ECU #
Green sticker, A11-612 424

I want to use the spare ECU as it fixes my idle issue (that I never knew about as I thought it was always normal) but I dont want to loose run with the TPS off either for the needed fuel enrichment.

 

connection pins are different on all the ones Iv got to check out

 

I found my spare ECU is a 79ZX and my stock one is a 80ZX I counted the pins and their the same on mine.

Now I'm mostly wondering is what does that early ECU seem to hate that TPS.

 

not sure, the afm/ecu relation is usually what doesent work out when your mixing ecu's

 

Well I already worked out that it doesnt like the full throttle on the TPS over 3K RPM. Tho if the pins are the same and the test result is the same though both years I dont think there should be much issue

 

open em up and compare both boards.


I dont think any of us have really looked into what exactly makes all the ECU's different.


cuz theres something different about all of them or Nissan wouldn't have given them different part numbers.

maybe some slightly different programing even?

 

I'm guessing its the program as they pretty much look the same. on the inside.

Ok now my issue is. Why does it stumble over 3K RPM at full throttle?