Misfiring, please I just want some opinions
03-05-2013, 04:14 PM
#1
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Misfiring, please I just want some opinions Ok so my PCM is reading that bank 1 is running lean, therefore it's pissing fuel into the engine, which is obviously washing the plugs, which is in turn causing the engine to misfire, I've taken the car to a shop, (it's an 02 m6 lts, ory, ftra, 25% udp,air!) he's changed out the o2 no change in the problem, swapped pcms, still nothing, checked the wires, nothing, and checked for vac and exhaust leaks, and fuel pressure and injectors, it's all of bank1 and I've already swapped spark plugs once, the old ones were replaced about a month ago and I put another set, just on bank 1 the other day (though I'm sure they're probably shot by now to) idk what else to do please please tell me someone has some input, I've looked all over and read pages and pages of thread
03-05-2013, 07:40 PM
#2
Which bank one cylinder is misfiring? The thread tittle is the only place it's mentioned.
Lean can cause misfire but.... misfire in itself causes unburned fuel to enter the exhaust that
the 02s don't see it reports lean and adds fuel.
misfire codes? compression check, cylinder balance test, look under the valve cover
rocker, valve spring carnage can sometimes be pretty quiet on the intake side.
Lean can cause misfire but.... misfire in itself causes unburned fuel to enter the exhaust that
the 02s don't see it reports lean and adds fuel.
misfire codes? compression check, cylinder balance test, look under the valve cover
rocker, valve spring carnage can sometimes be pretty quiet on the intake side.
Last edited by sreve; 03-05-2013 at 07:52 PM.
03-05-2013, 08:10 PM
#3
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From what the guy says that owns the shop, he says the reason it's misfiring is because the engine thinks its running lean on bank 1 so it's pouring all of this fuel in there which is flooding the plugs, I can attest to that fact because I pulled all the plugs on the drivers side and they were terrible and the ones on the passengers side were fine, he says the PCM isn't reading anything from the o2 but he tested the o2 and the PCM and the wiring by replacing them with another o2 and PCM that he knew was good, there was no change
03-06-2013, 06:34 PM
#7
The recommendation to unplug the 02 sensors is also good. The computer will compensate for missing signals. If you still have an issue with only one bank running rich you know it is not the 02 sensors if they are unplugged.
You could also try swapping sensors from one side to the other to see if the problem follows the sensors. You can do them your self they are easy, you need a 7/8 wrench to remove them. Don't mess with the rear 02's if you have any, just the front ones. I assume that you only have fronts if you have long tubes. Well, you should only have fronts.
You don't have an exhaust leak do you? That can throw off the 02 readings.
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03-06-2013, 08:21 PM
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If it's misfiring then O2 sensors will indicate lean
regardless of actual incoming AFR, and drive your
fuel trims into the weeds. Which causes which, is
the question. Begin by resetting fuel trims and see
if the misfire counts settle down, or if they continue
to pop and the trimming goes back to whack.
regardless of actual incoming AFR, and drive your
fuel trims into the weeds. Which causes which, is
the question. Begin by resetting fuel trims and see
if the misfire counts settle down, or if they continue
to pop and the trimming goes back to whack.