With a '97 ECM and '97 bungs, then the only difference front and back is wire length. If the front has enough length, then good to go.

Clean the connectors and load up with dielectric grease.

 

Why would you "load [them] up with dialectric grease"? The grease is designed to be an insulator (prevents the flow of electrons/electricity) so by adding the grease you're only increasing the chances of a bad connection.

Clean the connectors with a standard pencil eraser and leave it at that.

 

if you have a good mechanical connection, the grease keeps crud and moisture out.

 

Dielectric grease does not impede flow of electrons from the metal to metal connection. What it does is reduce corrosion on the area of metal it does cover by keeping air and water and, yes, crud, out. It also reduces or eliminates current leakage away from the connection. That's what its for. If you don't have a good connection with the grease, you don't have a good connection, period.

 

Well, put new sensors in a same thing.

No idea what to do.

My only plan is to bypass the harness and run my own wires from the ECM to the sensors. Maybe something is wrong in the harness. Unlikely but I really don't know what else to try.

Any other ideas out there?

 

This just sucks. I don't know, you don't know. Don't nobody know.

 

STILL stuck on this if any new eyes sees this and has insight.



I have ohmed out the wires between the ECM and the sensors and the corresponding pins on the plugs. In fact, I have done this a bunch of times. Each time they appear to show perfect continuity.

I have replaced both O2 sensors.

I have tried another ECM with exact same part number

I have replace the MAF with know good unit.

I have Confirmed ign power and ground to sensors

I have jumped wires for each individual O2 heater wire from ECM straight to O2 sensor pin.

I have jumped power and ground straight from alternative sources to O2 sensors.

Everything I have done results in the same immediate P0135 and P0141 codes.

I have no idea where to go from here.

 

Isn't there another ground from intake manifold to firewall and maybe yet another from the diagnostic port to manifold. My hunch every time is grounding. Also good ecu ground?

 

ground from motor to firewall is there and hooked up.
I ran a new ground wire from battery to ground point on intake to sure it up.
I ran a ground from bare metal to O2 sensor about 4-5" up the harness just to be sure.

I keep thinking ground as well so I have doubled up everything I can think of.

the correct pins on the O2 sensor show power and ground with motor running

 

Finally!! Success!!

Turns out the E03 ground that feeds the O2 heater was loose in the pin of the computer plug. It was intermittent so sometimes it showed good and sometimes not. I had tested this multiple times, but with just a standard meter, it didn't show the faulty connection. A neighbor brought over his Snap On oscilloscope and that showed the weakness of the ground.

Took the female pin out and closed it up with some pliers a bit and made it tighter in there and everything is working great.

Funny things is I had pulled the same pin multiple times and I thought it was good. It looked good, tested good on a meter, etc. turns out it wasn't.

Moral of the story, when in doubt find someone with a $3000 piece of testing equipment.

 

Excellent! Glad you found the wiring gremlin.

 

OH. MY. GODS. What a great resolution!

 

Interesting.