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Bad O2 sensor or clogged injector????

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Old 11-18-2010, 01:07 PM
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Default Bad O2 sensor or clogged injector????

Well i have been having this weird problem with the truck lately. It was happened about 4 times in the last few weeks... Bank1 will peg the LTFT at +25.... But if i stop, turn off the truck and restart it, it clears up.... I am either thinking that a clogged up fuel injector is causing it or a bad O2 sensor... When it happened today, i checked the O2 voltage with the aeroforce gauge, and it read steady 490-500mv, Bank2 was switching like normal.

Any ideas? what has me stumped is when i turn off the truck it is fine until the next time it happens.... Also my retarded *** has the misfires setting zeroed out so i can't tell which cylinder, if any is causing it...
Old 11-18-2010, 01:14 PM
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Add the misfire diagnostics back in, then check it out.
Old 11-18-2010, 01:16 PM
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Honestly i don't know if that is a decent option... Given the dual springs and cam profile i run, i will get misfires on all the cylinders....
Old 11-18-2010, 01:19 PM
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Mine did the same thing. Jacked up o2's was my problem. My thread is somewhere on here. If it comes back...I will swap in the replacement injectors I bought just in case.
Old 11-18-2010, 01:19 PM
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Try swapping the O2s side to side and see if the code follows the sensor?
Old 11-18-2010, 01:21 PM
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I am not getting a code, just an ocassional lean condition... Also if the O2 sensor was dead/dying, i would assume it would flat line at 0mv or 999mv, correct?
Old 11-18-2010, 01:23 PM
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Originally Posted by BlackGMC
I am not getting a code, just an ocassional lean condition... Also if the O2 sensor was dead/dying, i would assume it would flat line at 0mv or 999mv, correct?
Dont know about the flat line...mine were just lazy. If you have HPT I included a run log that you can look at in my thread which shows the lazy o2 and high LTFT.

https://www.performancetrucks.net/fo...d.php?t=470974
Old 11-18-2010, 01:27 PM
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Well my O2 sensors have less that 3k on them, i just replaced them not too long ago... Also right around that time, i swapped in "new" (well supposedly new) #31 injectors, and TBSS manifold, and new Walbro fuel pump...

I am gonna pull out the O2 sensors and get them replaced under warranty, take out the injectors and clean them... Hopefully i will know more Saturday.
Old 11-18-2010, 01:34 PM
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Originally Posted by BlackGMC
Honestly i don't know if that is a decent option... Given the dual springs and cam profile i run, i will get misfires on all the cylinders....
Yes, it will show some misfires on all cylinders. But whichever cylinder has a BIG problem will count way higher(moniter misfire counts while datalogging). At least then you can narrow it down to one or two cylinders. Then swap the injector, coil, wire, and plug all to different cylinders. Follow the misfires to your failing part.
Old 11-18-2010, 01:47 PM
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Originally Posted by AKlowriderZ71
Yes, it will show some misfires on all cylinders. But whichever cylinder has a BIG problem will count way higher(moniter misfire counts while datalogging). At least then you can narrow it down to one or two cylinders. Then swap the injector, coil, wire, and plug all to different cylinders. Follow the misfires to your failing part.
ok i will give that a shot.


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