2004 5.3 vortec O2 sensor MV/switching q?
03-22-2016 | 04:07 PM
#1
Alright guys I'm helping a friend diagnose his 5.3 swap C10.
2004 5.3 vortec, stock exhaust manifolds with no cats, dumped exhaust before the rear end.
We're chasing p0171/p0174 codes, then p0300 pops up after them.
I have a scanner on his truck and we drove around the block at about 15-25 mph and during any throttle pull the bank 2-1 sensor reads .000-.030 and the bank 1-1 sensor is pegged @.900
They are not switching back and forth, at idle the bank 2-1 sensor reads .000
With KOEO we get .450mv for the front o2's constant, even after a min they don't change.
I know .450mv is default of an o2 sensor gets unplugged or whatnot, but should a good sensors MV go up or down with the engine off and letting them heat up slowly?
His MAF sensor g/s is rising and falling with the throttle so that seems like it's working.
Any advice?
I attached a photo of a 1,500-2,000 rpm pull, it's stuttering really bad in this area
This is what the o2 sensors look like, the rears are deleted by the way.
2004 5.3 vortec, stock exhaust manifolds with no cats, dumped exhaust before the rear end.
We're chasing p0171/p0174 codes, then p0300 pops up after them.
I have a scanner on his truck and we drove around the block at about 15-25 mph and during any throttle pull the bank 2-1 sensor reads .000-.030 and the bank 1-1 sensor is pegged @.900
They are not switching back and forth, at idle the bank 2-1 sensor reads .000
With KOEO we get .450mv for the front o2's constant, even after a min they don't change.
I know .450mv is default of an o2 sensor gets unplugged or whatnot, but should a good sensors MV go up or down with the engine off and letting them heat up slowly?
His MAF sensor g/s is rising and falling with the throttle so that seems like it's working.
Any advice?
I attached a photo of a 1,500-2,000 rpm pull, it's stuttering really bad in this area
This is what the o2 sensors look like, the rears are deleted by the way.
Last edited by Burken01; 03-22-2016 at 04:19 PM.
03-22-2016 | 08:23 PM
#3
Driver Side o2 is before the collector, then welded to the exhaust pipe
Passenger o2 is about 8"-12" away from the collector if I had to guess
I haven't checked if the harness is crossed, I don't think they would reach to each other's side but it's worth a shot to check..
03-23-2016 | 07:48 AM
#4
Really does sound like crossed O2 wires. Bank 1 pegged at .9mV is calling for less fuel. Bank 2 at 0 to .03mV is screaming for more fuel. I bet your fuel trims are pegged LTFT1 -25% and LTFT2 +25% but with the O2 connections crossed the fuel trims are just keeping the O2 sensors pegged the wrong way.
03-23-2016 | 11:02 AM
#5
Really does sound like crossed O2 wires. Bank 1 pegged at .9mV is calling for less fuel. Bank 2 at 0 to .03mV is screaming for more fuel. I bet your fuel trims are pegged LTFT1 -25% and LTFT2 +25% but with the O2 connections crossed the fuel trims are just keeping the O2 sensors pegged the wrong way.
03-23-2016 | 11:36 PM
#6
Just wanted to update the thread, swapped o2 harnesses.. O2's started switching properly and fuel trims immediately picked up and got better..
Hopefully this helps someone if they run into crossed o2 issues.
I need to purchase hp tuners again and dump this baby scanner I have lol
Hopefully this helps someone if they run into crossed o2 issues.
I need to purchase hp tuners again and dump this baby scanner I have lol