Well I've got my car back, had a shop help me put it back together, and they did a pretty good job from the looks of it.

I'm about to go out of my mind here. I'm on my third set of AC Delco Rapid-Fire plugs ($35 each time). One thing that I need some help with. When I have Diacom plugged in, my Oxygen sensor reads 451 mV with the car off. As soon as I turn the car on, it goes to 0 and stays there indefinitely, open or closed loop, it doesn't matter.

I have changed the heads, headers and fuel injectors. I am using Dart Pro One heads, Hooker 2149 Headers and Accel 30# fuel injectors (up from 22# injectors, and yes I have a custom chip burner for the switch). It had been suggested that maybe the oxygen sensor wasn't reaching 600 degrees, therefore wouldn't give a reading back to the ECM. So another suggestion was to buy a heated Oxygen Sensor (as you might have seen from my other posts). That is all hooked up and spliced in. Black lead to the ECM and one white lead is grounded, the other is hooked up to the windshield wiper motor hot. As far as I can tell, it's hooked in correctly. But still no reading. I know I'm not lean, because I can put the stock GM chip back in and I will fuel foul my plugs in a matter of 20 miles, still with no voltage reading on the O2. The computer thinks it's lean so it's dumping excessive fuel in and fouling the plugs.

What could be wrong?



[Modified by sspackman, 9:26 PM 3/30/2003]

 

:banghead:

I'm throwing idea's here...
Did you double check the wiper motor hot and make sure it is switched Ign and is hot?
Did you use the diacom software before you did the motor?Did it work then?

 

Thanks for the reply. Yep, I double checked the wiper motor hot before and after the soldering job.

Unfortunately, I didn't have Diacom before the switchout on the motor.

Thanks,
Shayne

 

Any other takers? Any guesses on what to check next?

 

Just throwing out an idea. Have you tried tracing the O2 wire back to the ECM to look for burned out/grounded wire? Maybe make a jumper from the O2 to the terminal on the ECM to see if that gives you an O2 reading.

Or maybe the ECM is just toast?

 

I would suggest finding the pin, not sure which one it is on the ECM and seeing if you have continuity from the sensor to the ECM, if not then the wire is cut or something. You can do a another check from as close to the sensor as possible, probe into the wire, and just up past your connection to make sure you have a good one. Then use that same probe spot at the sensor to check to the ECM pin, both should show very little restistance.

And yes as bill indicated, once you find the correct pin on the ECM you can run a jumper from there to the sensor to see if it then get a signal. The engine shop very easily could have pinched a wire and cut off the comunication to the sensor. I think the wire itself runs through the harness to out under the hood, If you find that the jumper works, i would just run another wire rather than searching for the bad connection.

Sure hope you find the problem and the chip works out for you!

Jesse :cheers:

 

Got it going again! Thanks for your help. There was a loose wire close to the firewall, so now it's running MUCH better.

Thanks for your help!