55 Nomad with LS1 o2 problems
03-28-2012, 12:46 PM
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55 Nomad with LS1 o2 problems I'm working on a 55 Chevy Nomad with an LS1 transplant, car starts and runs fine until the weather changes. On my scanner, its shows both o2 sensors are barely working at all but they have just been replaced. It also doesnt seem to be trying to compensate for any changes. The short and long term fuels trims are not doing anything. Just sitting at zero. Any ideas? Going to check all grounds and ohm the wires to each sensor tomorrow.....
Thanks in advance
Thanks in advance
03-28-2012, 06:35 PM
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Did you use a harness from a transplant car? If so, are you sure you used the front O2 sensor leads? If you used the rears by mistake, it will not go into closed loop... To check, read the rear O2 sensors with your scanner and see if they are doing anything.
03-29-2012, 06:56 AM
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Its actually a Street & Performance harness. I've run into an issue like this before and fixed it by changing PCM's. The owner called yesterday and said he had noticed some wires that looked "twisted up" near the o2's. Gonna try to get with him today and do some troubleshooting. I will check and make sure that it doesn't have the plugs swapped around also. Thanks for the reply!
04-03-2012, 07:12 AM
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Ok guys, just wanted to give you guys an update. After pinning wires for 4hr sat, we found bank 2 sensor 1 had two pins swapped. Corrected that by repinning connector. Yay, passenger O2 works but still no closed loop. Got an injector control circuit code, started pinning injectors.......tada number 3 injector wires were both showing power. I can only assume that they are shorted back inside the harness. Anyway, ran new wire out to the injector plug, repinned the pcm, and everything works! Car is way more responsive now and easily smokes the tires all the way through 2nd. Still getting a random MAP sensor performance code.....Any ideas on that or could it be in the wiring also?
