How to tell if left and right O2 sensors are wired backwards?
08-21-2018, 07:49 PM
#1
How to tell if left and right O2 sensors are wired backwards? Finishing up LS swap on my Wagoneer, and it bogs down bad after warming up. Getting O2 sensor code. I have one sensor lead on the same loom as the MAF sensor and the other on the 4L60E main pigtail. Which is left and right? Would having them swapped cause the bogging/low (400) idle problem? Thanks a lot.
08-22-2018, 08:12 AM
#2
A Jeep swap I helped fixed had the issue of the O2s being swapped. It would idle fine until it warmed up (went into closed loop)
You could tell they were switched because when you scan using HPTuners, bank 1 and bank 2 O2 sensors, in the chart the (o2 value vs time) usually each bank traces the other, but since they were switched, bank 1 would go super lean as bank 2 went super rich (PCM was adding/taking away fuel to the wrong bank and it just kept going to infinity)
Check the wiring on each O2 sensor. The sensor with a solid purple wire should be your Bank 2, passenger side sensor. Purple/White should be Bank 1, driver's side sensor.
Or it could be a vacuum leak, make sure all the ports on the intake are capped off. Also make sure all of your grounds are nice and tight (and all are connected). Wiring harness groundS, engine to frame ground, frame to body ground, body to engine ground. A bad ground will cause bogging issue
You could tell they were switched because when you scan using HPTuners, bank 1 and bank 2 O2 sensors, in the chart the (o2 value vs time) usually each bank traces the other, but since they were switched, bank 1 would go super lean as bank 2 went super rich (PCM was adding/taking away fuel to the wrong bank and it just kept going to infinity)
Check the wiring on each O2 sensor. The sensor with a solid purple wire should be your Bank 2, passenger side sensor. Purple/White should be Bank 1, driver's side sensor.
Or it could be a vacuum leak, make sure all the ports on the intake are capped off. Also make sure all of your grounds are nice and tight (and all are connected). Wiring harness groundS, engine to frame ground, frame to body ground, body to engine ground. A bad ground will cause bogging issue
Last edited by TXjeepTJ; 08-23-2018 at 02:00 PM.
08-22-2018, 09:58 AM
#3
The trans pigtail is always Bank1 Driver side. The long side with the maf is Bank2 Passenger side.
Sometimes the maf will be up near the tb location, so it makes figuring out the o2 a lil more trickier. But almost always the o2 pigtail next to the trans PN switch will be Bank1 Driver side!
Sometimes the maf will be up near the tb location, so it makes figuring out the o2 a lil more trickier. But almost always the o2 pigtail next to the trans PN switch will be Bank1 Driver side!
08-22-2018, 04:57 PM
#6
Yea, but the actual trans harness branches off and goes around by the PN switch thin crosses over to the paseenger side for the main pigtail.
Like i said, the o2 pigtail tht is beside the PN switch will be bank1. On most harness the bank2 o2 pigtail is not on the same trans section of the harness.
Like i said, the o2 pigtail tht is beside the PN switch will be bank1. On most harness the bank2 o2 pigtail is not on the same trans section of the harness.
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08-22-2018, 10:30 PM
#9
TECH Senior Member
Does it run better?
08-23-2018, 05:45 PM
#11
TECH Senior Member
Good deal! Keep us posted on how she does!
08-26-2018, 11:56 AM
#13
TECH Senior Member
Good deal! Glad to hear it! Have mucho FUN!
