Hey, those extensions are great, I have 4 sitting on the bench now, going to use them on the reinstall. It's ridiculous what it takes to access those connectors. (my brother has a Defender, and that thing has enough room in the engine compartment for 2 beer coolers and a stripper).

 

Ok, so I got a new Bosch and a Walker. Dropped the Bosch in, powered up at .455v then started the death creep to zero and hung there, no changes from the one I pulled.

Put in the Walker, it powered up to .455v, then started dropping and climbing just like it's supposed to. Took her for a spin, 20 miles out and back. First 15 miles everything worked great, last 5 miles it started hanging on the low end around .155...then dropped to zero and held. But, it didn't throw a light, yet. The interesting thing is that S2 was down around .115-.080 where previously it would nail .900 when S1 hit zero.

I re-checked the harness and connectors all good, everything clean as a whistle. Bank 1 works like a champ but it definitely has something going on in bank 2. Back to square one.

 

Swap left and right and see what happens. It is possible you have some sort of vacuum leak on that bank and the LTFT just can't adjust enough, however in that scenario it would start low and creep towards .5 but never quite reach it.

 

I had a similar problem almost three years ago. Right now I don't recall how I solved it, but I did learn you can bench test O2 sensors with a handheld propane torch, which I just happened to have already. There are YouTube videos, I think. You connect a multimeter to the two correct recesses in the connector, then heat the tip with the torch. Once heated you can see the volts generated and you can see the responsiveness of the sensor as you move the torch away from and back to the sensor and watch the voltage go up and down (hopefully). That allows you to either rule out or confirm whether or not the sensor is the problem.

 

Replying to Extinct:

Ok, I swapped the sensors. Same deal on Bank 2

At startup:
LT Trim Bank 1 - 2.3
LT Trim Bank 2 - 14.8
short term bank/sensor bank 1/1 3.9
short term bank/sensor 2/1 25.0
short term trim bank 1 1.6
short term trim bank 2 25.0
B1S1 .435
B2S2 .445
B2S1 .440
B2S2 .450

15 min running:

LT Trim bank 1 - 2.3
LT Trim bank 2 - 14.8
short term bank/sensor 1/1 -3.1
short term bank/sensor 2/1 25.0
short term trim bank 1 -0.8
short term trim bank 2 25.0
B1S1 .125 (next frame over this goes to .460 then to 180, so it's not static)
B1S2 .445
B2S1. 025 (this sensor starts out oscillating...then starts declining)
B2S2 .450

I know "what" I'm looking at, just not what it's telling me. ( can see that B1 and B2 are WAY off from each other but not why)

 

Thanks...I actually used my MAP torch to check the sensor, and it's working both on the bench and in the drivers side (LH) bank. Something hinky in Bank 2 and for some reason I'm not getting hip to the mumbo. I should know what this is, but I can't put my finger on it.

Sorry guys, I' not too sharp on using the board and don't always get the reply in the right spot to the right person. I greatly appreciate your time and knowledge in helping me solve this. (yeah I'm the guy that never uses a map to navigate cause I "know" where I'm going, just ask y wife)

 

Hey Gary. I just looked up my thread from three years ago (linked below; see post #3 from Best4x4). Have you cleared the ECM adaptive settings? It's easy to do; just disconnect the battery for a minute or so. That may solve your problem. Good luck! And please let us know what happens next.

 

I'll do that first thing in the morning. thanks!

 

Ok, good test on swapping left and right. That tells us the 02 is good, and whatever the problem is seems to be located either on bank 2 of the engine or in the bank 2 circuitry. Your fuel trims indicate the ECU is throwing all the fuel it can at bank 2, but it still cannot raise the voltage. It appears as your engine warms up it gets progressively leaner on that side. Note with the same amount of fuel a warm engine should actually be richer than a cold one, so yours is actually working in reverse. I doubt it is just one cylinder, that likely would not have this big of an impact without a miss. It would be strange indeed to have partially plugged injectors on one side only, however we may consider swapping left to right injectors just to rule out an injector issue - lets come back to that. The power steering booster and PCV valve vacuum ports are directly over the bank 2 intake manifold junction at the main front intake plenum tube, although it would not be directly isolated to that bank, if those were leaking air they might have an outsized influence on that bank. You could pull both off and plug them just to do a test and see if it changes. It is possible your power brake booster has a hole in it causing a vacuum leak without you knowing it. Other potential leaks on that side include the intake gaskets and injector o-rings, although if you did not change anything recently those are unlikely to have this size effect. I pretty sure you can rule out bad coils/wires/plugs - those would cause a rich condition not a lean one.

I would recommend plugging those vacuum lines and see what happens. If that does not solve the issue I would probably swap injectors left to right just rule that out, then I would consider an ECU swap (I have the benefit of 4 running trucks and three spare ECU's). You could buy a used ECU/BCU/Cluster combo off of ebay to test with and just resell it for what you paid for it if you don't need it - basically free test parts.

Let us know what you find out.

 

I was thinking PCV as well. Easy to check.