Alright, so here's the deal. I passed the emissions with some really good readings with my stock 89 240 fastback. When i drove it from the shop the check engine light was off then later during the day, the check engine light came back on.. The mechanic at the shop said the cause for the check engine light the first time i brought it to the shop was because of the injectors and that they were dirty i needed injector connectors. So the mechanic took care of that problem. But another shop told me that my wiring was a little messed up. So i took care of the things that needed to be repaired in order for me to pass emissions and i did. What could be the problem of the check engine light? my wiring harness? possible short?

 

What code does it give out man? Do you know how to read the codes? I should ask if you know where your ECU is at, you could do this yourself man.

 

yes, i know how to read codes, and i know where the ecu is.. i'm not a beginner in cars.i use to fix hondas for fun but as far as nissans..it's been quite a while.i forgot what the code was but it was an injector something but the shop fixed injector problems. This other shop like i mentioned said that the wiring harness was pretty messed up and there could be a short in the wiring harness causing the the ecu to shoot out different codes.

 

That would be a possibility. But if your harness is shorting somewhere and touching something else, then you should have other problems, like fuses blowing out, and or electrical problems. Sensors go bad and give weird readings. Or the ECU is just acting weird. Injector problems can be caused by other things as well. I had an injector get clogged and they cleaned it out, and cleared the code. 2 months later my check engine light came on.
It was the Injector again, this time I checked my distributor/ cap and wires and found one of the contacts was totally f***ed up, looked rusted and white crap was in cap. No more injector problem dude.
Hope that helps.

 

here is the website that show u the codes for nissan

http://www.ka24development.com/ecu_codes.html

 

IT could be a possiblity of another code such as an EGR valve or a knock sensor.

 

thanks peeps