O2 Sensor readings
O2 Sensor readings So I just finished my swap with an LM4 that has an ls6 cam in it. I am running off an 0411 pcm and harness that came from a 4.8 silverado and I uses hptuners to switch everything to a stock 5.3 tune. I don't have a wide band so I have been trying to work off of the narrow bands and after driving a bit, bank 1 is switching high and low as I would expect and the fuel trims for that side are positive which I think is expected given the cam should be flowing more air correct? However, bank 2 is showing like -13 and the O2 is not switching, it either sits at 498 mv or 1019 mv. I thought maybe it was a bad connection since I reworked the harness myself but I have a tan wire running from the plug to pin 29 on the PCM and it isn't broken. I put a wire tap on that wire and hooked my meter up and it was showing less than 30 mv even though HP was still showing 498 or 1019! So I checked the Bank 1 signal and it was also not matching up with what was showing in HP either but it was at least closer. I am just trying to figure out what is going on and why they wouldn't be the same, am I missing something? Any help would be appreciated, thanks in advance!
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
Sounds like a bad sensor. Try swapping it over to the other side and see if it fault follows. They do go bad over time. And if it is bad, replace them both, because that means the other one is probably not far behind it.
They are both brand new. I ordered another one to swap it with but I am still not getting why HP is so different from my multi meter
Thanks but that doesn't help. All I am trying to do is get it semi drivable before I take it to the dyno and use their wideband. Also, the funky readings happen even with the engine off so the cam has nothing to do with it.
TECH Fanatic
Joined: Oct 2014
Posts: 1,220
Likes: 179
From: Virginia
Also, if there is any obstructions in the areas around the wires on the back of the sensor, it won't work too well, if at all. Like dirt or anything that can block the air from coming in the back. They need that air to in order to compare the "difference" from inside the pipe and outside. The greater that "difference" the more voltage is produced. Worth a look at least. I've had a few sensors that were bad out of the box. It's not beyond reason.
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