What went wrong?

Recently I've replaced a fried ECU, and was diagnosed with dead O2 sensor. I have 2 others..... both of them keep the checck engine light on. Perhaps the wiring connecctors TO (from the wiring harnesses) the O2 sensor connectors have gone bad?

Or maybe the O2 isn't grounded properly and caused my ECU to fry earlier.


? Any suggestions?

-Phil

Have you recently replaced the header?
Alot of times the header has a ceramic coating on it that will keep the O2 sensor from grounding properly.
Also check the round strap from the catalytic converter to the body.

And did you completly and correctly resrt the ECU after you instaled it?


Rick

My car's completely stock (P10 G20, 1994)


Headers are stock. So I'm assuming your referring to the ceramic HS gen 5 headers...... i dont have.
Where exactly is the ground strap near the cat covertor? I've looked arouund here and there, can't seem to find it...


-Phil

Have you checked all fuses? Maybe one is incorrectly installed in a slot for a lower amp setting. That would make sense. I'd also check ALL grounds. It doesn't necessarily have to be the O2 that is the problem.

I'll look through all my fuse diagrams ....... problem is i dont have a FSM, so im not sure of ALL my fuse boxes. I only KNOW about hte ones listed in the user manual.... (they might hide some sometimes..... i've heard about NX2000 manuals haha.)

Where exactly is the ground by the cat?

Originally posted by ricecube77
Where exactly is the ground by the cat?

It's just a bolt on the chassis by where the header secondary connects to the cat.

Bump:

Anyone know where the fuse is for the Front Heated O2 sensor?

i dont think there is a fuse for the O2 senser, its just a switch

Bump:

i checked the ground connection near the cat conv...... seems to be fine.

Anyone have ideas on the wiring setup for the front O2 sensor? ......... is the middle one a ground? or does the O2 ground through the engine....?