Low reference wires on E38
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Joined: Oct 2023
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Low reference wires on E38 Hello, new to forum. I don't have a F body......but have 08 Silverado and 11 Suburban. Both are 5.3. I'm having O2 sensor issues with the suburban. Keeps saying stuck lean or insufficient switching. I find hard to believe new Bosch sensors are bad. I have run new chassis grounds firewall to head to head to block to frame back to firewall. Even new ground from PCM ground wire to block. Still having issues. Saw a post here thru a search that I now can't find. It was about tieing all the low reference wires together.......but where do I run them to if I do this? Low reference wires are basically sensor grounds aren't they? I have new O2 sensors on order just in case. Thanks for help. Matt.
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Joined: Jan 2018
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From: Dade City, Fl.
My experience is always use ntk/ngk or Denso instead of Bosch on a GM vehicle. Same with spark plugs. Video
History...? Were the only dtc's you received p1133 and p1153 ? Before and after the sensor replacements?
History...? Were the only dtc's you received p1133 and p1153 ? Before and after the sensor replacements?
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Joined: Aug 2005
Posts: 672
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From: Washington Crossing, PA
Well I've got exhaust leaks but very small ones at connection points further down the exhaust. But the y-pipe connection to the driver side header has no leaks which is the side I'm throwing the code for, p1133. No fuel pressure issues either, I have a gauge for that in the car.
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Verdad Gallardo TECH Enthusiast
Joined: Aug 2005
Posts: 672
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From: Washington Crossing, PA
Car got a cam change and procharger 12 years ago along with a new tune, that was the last time it got any mods. Before that I put in new up stream denso 02's. No codes until last summer it started to throw a p1133 code here and there. By late summer/fall time it started to happen more and more. Now that the weather is nice here and I'm starting to drive the car again, I'm still getting the same code. The last 2 times I pulled the code it's showing it was lean on that side and adding fuel when the code set. Just put in 2 new denso 02's and still getting the code.