56 Belair with LS7 o2 problems
 

I put an LS7 in a 56 Belair we are building for a customer. The problem we are having is that on the laptop, the o2 sensor readings are staying steady at around 445.

Here's a little history. We bought what we were told is a 2010 LS7 from Don Hardy race cars. It had the factory harness on it but the connectors to the ecm were damaged. The engine also came with a brand new in the box GM ECM.

The harness was made into a stand alone harness and then sent to Current Performance in Florida to put on new ECM connectors. The ECM was sent to Jessie at Wait4me performance to flash it since it was brand new and never been in a car.

According to my tuner guy, the computer shows up as a 2008 model. I don't know if this makes any difference considering I have what is supposedly a 2010 harness.

We have checked the pink wires at the o2 sensors and know we have battery power there. We replaced both sensors with new ones and nothing changed. The fuse for the o2's and MAF is good. There are no rear o2 sensors in the system at all. Everything else is working correctly and the car actually runs pretty good.

Where should we go from here?

Thanks,
Doug

Run a log and see if the rear O2s are showing any activity - make sure they didn't use the wrong pins...

Have your tuner guy look and see if Jesse set it up to run in Open Loop, aka not reference the O2's.

Ok, we have tested all 6 wires from the front o2 sensors all the way to the correct pins in the ecm connector so we know that the wiring there is good. The rear o2's are showing 0 activity. We know that the sensors are turned on because we can also turn them off. When we turn them off, the car runs the best, but obviously not correctly. When we turn them back on, the idle goes crazy. I assume because it's looking for the o2's.

After we put in 2 new sensors, one started to show some activity. The other did not show anything. I guess I'm going to try 2 new sensors again just to see what happens. The sensors we are using are Delco brand if that makes any difference.

Thanks for the help.

We got it fixed.

We plugged in another computer to check what would happen so we could rule out a computer problem. With that computer the left side o2 was working, the right side had nothing.

So, we went back to our original computer and everything works fine. WTH?? Maybe dirty pins? I don't know, but the tune is in and the car drives like a bat out of hell.

Thanks for the suggestions and help.

Doug