Odd O2 Voltage Problem
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On The Tree
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From: Fort Lauderdale, FL
Odd O2 Voltage Problem I spent the entire day trouble shooting an odd O2 voltage issue. My tuner noticed that the voltage for bank 1 (Left/Drivers Side) is lazy and inconsistent. I have installed 2 brand new AC Delco oxygen sensors and swapped them from either side. The problem stays on Bank 1. Upon initial start both O2s read almost identical 0.455v’ish. As the engine warms up Bank 1 start’s to fall off as Bank 2 starts to increase. If I blip the throttle, they both shoot up over .600 volts. Towards the end of the short data logs I made I noticed that Bank 1 has a slightly lower voltage off idle than Bank 2. At idle bank one will read 0.032v’ish. But as soon as you blip the throttle it shoots up.
I have changed the harness connector twice. Swapped the o2s around, and tried a set of Denso O2s. All create the same problem. I am %99 sure there are no exhaust leaks. Only difference between Bank 2 and Bank 1 is Bank 1 has a new connector soldered and heat shrinked on. Shielded with silicone coated fiberglass heat shield. Both Bank 1 and Bank 2 O2 wires read 0,2-0.3 ohms back to the PCM. Spark plugs look good. Not too rich, not too lean. Engine is an 11:1, 355 LT1, with LE2 heads, LE custom grind Hyd roller (224/230 .573/.568 110 LSA), 32lbhr Bosh III injectors, Long tube headers, X pipe dumping before rear axle. No Cats, Smog pump, EGR.
EDIT:
Here is the Datamaster file: http://www.freefilehosting.net/copyofrun1
Here is the FreeScan File: http://www.freefilehosting.net/runone
I can email them to whoever is interested in looking at them. Shoot me a PM or an email at LT1Garage@gmail.com
Anyone have any Ideas WTF?
Thanks in advance
I have changed the harness connector twice. Swapped the o2s around, and tried a set of Denso O2s. All create the same problem. I am %99 sure there are no exhaust leaks. Only difference between Bank 2 and Bank 1 is Bank 1 has a new connector soldered and heat shrinked on. Shielded with silicone coated fiberglass heat shield. Both Bank 1 and Bank 2 O2 wires read 0,2-0.3 ohms back to the PCM. Spark plugs look good. Not too rich, not too lean. Engine is an 11:1, 355 LT1, with LE2 heads, LE custom grind Hyd roller (224/230 .573/.568 110 LSA), 32lbhr Bosh III injectors, Long tube headers, X pipe dumping before rear axle. No Cats, Smog pump, EGR.
EDIT:
Here is the Datamaster file: http://www.freefilehosting.net/copyofrun1
Here is the FreeScan File: http://www.freefilehosting.net/runone
I can email them to whoever is interested in looking at them. Shoot me a PM or an email at LT1Garage@gmail.com
Anyone have any Ideas WTF?
Thanks in advance
Last edited by BlownEarDrums; Jul 1, 2012 at 10:29 AM.
Thread Starter
On The Tree
iTrader: (2)
Joined: May 2008
Posts: 138
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From: Fort Lauderdale, FL
I have tried a handful of other tunes that were calibrated for similar modded engines only to have the same problem reoccur. The problem doesn't change between open or closed loop. BLM's are locked in the baseline tune. Still scratching my head on this one.
Thread Starter
On The Tree
iTrader: (2)
Joined: May 2008
Posts: 138
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From: Fort Lauderdale, FL
Well… Problem solved. After shooting each primary with my IR temp gun. I noticed that cyl number 5 wasn’t firing. Took my stethoscope to the injector and found it wasn’t firing. Went to disconnect the injector plug and the damn 12v+ wire fell out. Soldered on a new plug and BAM. Car runs much better and no more uneven O2 readings. Odd thing is the car ran like a top when it warmed up. I always figured the hesitation was tune related since it changed with heat.
