O2 Sensor readings

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May 9, 2019 | 08:25 AM

whatthekrapp

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From: Indiana

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!

May 9, 2019 | 10:28 AM

G Atsma

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From: Central Cal.

1. Gen III 5.3's don't really like LS6 cams, ESPECIALLY is still using a stock 5.3tune.
2. Get a wideband. You can't tune with narrowbands

May 9, 2019 | 10:33 AM

ChopperDoc

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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.

May 9, 2019 | 10:43 AM

whatthekrapp

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From: Indiana

Quote:

Originally Posted by ChopperDoc

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

May 9, 2019 | 10:48 AM

whatthekrapp

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Quote:

Originally Posted by G Atsma

1. Gen III 5.3's don't really like LS6 cams, ESPECIALLY is still using a stock 5.3tune.
2. Get a wideband. You can't tune with narrowbands

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.

May 9, 2019 | 10:53 AM

G Atsma

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All I meant about the cam is that you will lose a LOT of low end power with it, especially with the stock 5.3 heads.

May 9, 2019 | 10:56 AM

ChopperDoc

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From: Virginia

Quote:

Originally Posted by whatthekrapp

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

That is pretty weird. You can try repolling the data, but I would try swapping them first just to see if it's in the software, the sensor, or something else. If the fault remains on that bank, then it could be a software issue or a wiring issue. If it follows over, well then you know.

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.