It's SMOG time and old faithful Rathtar is failing. I went through this truckmare end of last year / beginning if this year but thought I had it running well. However, after heading to the smog shop it failed as follows:
I went home in disbelief and despair, popped the hood, and started measuring junk. VF1 was 3.5V and VF2 was .060V. Both O2 sensors were flip flopping like you'd expect but at idle OX2 was slower than spec (8X in 10 sec). Bank 1 was enrichening the mixture while bank 2 was desperately and severely trying to lean it out. When I revved the engine, even a little over 1k RPM, the VF voltages would start to track to 2.25V which is on point probably why it passed at high idle. At idle, they would start to diverge. I found loose spark plugs so replace them with NGK Iridiums, new wires, cap and rotor. This helped the OX readings at idle a little. I wrapped my header wrap to the cat and that also helped but still, VF2 kept dropping often to 60-70mV. The plugs looked good with the loose ones looking like they got a little hot as one might expect.
I replaced the O2 sensors which were the stubby variety with NGK's that are the more well endowed variety similar to the Denso's (that I cannot find anywhere). Immediately, the VF voltages flipped. VF1 was 60mV and 2 was 2.25V. I went for a long drive and thereafter both were 2.24-5V which is on point. I drove my kid to school the next morning and upon return, same, both VF voltages were excellent. I went to smog it again today and failed even worse...
At idle, VF1 is 1.04V and OX1 is at 0.93-4V with little movement. The computer is trimming bank 1 lean, though not extremely lean while the O2 sensor reflects no oxygen thus a high voltage which makes me believe the O2 sensor is correct based on the rich test readings. VF2, is sitting on 60mV while OX2 is running closed loop flip flopping like you'd expect. Here the computer is severely trimming back fuel which might explain the loads of residual O2.
The truck has exceptionally good power. Out here on I15 I can blast up hills in top gear. It idles fine. Of course I have no CEL.
So, maybe the two banks can only trim so far apart from one another and so it can't get Bank 2 in spec because Bank 1 is as far as it can go? Maybe I just have a new but bad O2 sensor? The shops exhaust gas analyzer is a good 3rd party observer here. I am struggling with this one. I can check fuel pressure - again - which passed before and after the new fuel pump, filter, and pressure regulator. Maybe I have a leaky in injector but then how did if pass high idle before but not now? If I had an AFM issue I'd expect that to impact both banks similarly as would any of the other global sensors vs. a large disparity bank to bank. Compression was damn perfect as of spring this year, hard to believe that tanked in only a few thousand miles...
Frank
I went home in disbelief and despair, popped the hood, and started measuring junk. VF1 was 3.5V and VF2 was .060V. Both O2 sensors were flip flopping like you'd expect but at idle OX2 was slower than spec (8X in 10 sec). Bank 1 was enrichening the mixture while bank 2 was desperately and severely trying to lean it out. When I revved the engine, even a little over 1k RPM, the VF voltages would start to track to 2.25V which is on point probably why it passed at high idle. At idle, they would start to diverge. I found loose spark plugs so replace them with NGK Iridiums, new wires, cap and rotor. This helped the OX readings at idle a little. I wrapped my header wrap to the cat and that also helped but still, VF2 kept dropping often to 60-70mV. The plugs looked good with the loose ones looking like they got a little hot as one might expect.
I replaced the O2 sensors which were the stubby variety with NGK's that are the more well endowed variety similar to the Denso's (that I cannot find anywhere). Immediately, the VF voltages flipped. VF1 was 60mV and 2 was 2.25V. I went for a long drive and thereafter both were 2.24-5V which is on point. I drove my kid to school the next morning and upon return, same, both VF voltages were excellent. I went to smog it again today and failed even worse...
At idle, VF1 is 1.04V and OX1 is at 0.93-4V with little movement. The computer is trimming bank 1 lean, though not extremely lean while the O2 sensor reflects no oxygen thus a high voltage which makes me believe the O2 sensor is correct based on the rich test readings. VF2, is sitting on 60mV while OX2 is running closed loop flip flopping like you'd expect. Here the computer is severely trimming back fuel which might explain the loads of residual O2.
The truck has exceptionally good power. Out here on I15 I can blast up hills in top gear. It idles fine. Of course I have no CEL.
So, maybe the two banks can only trim so far apart from one another and so it can't get Bank 2 in spec because Bank 1 is as far as it can go? Maybe I just have a new but bad O2 sensor? The shops exhaust gas analyzer is a good 3rd party observer here. I am struggling with this one. I can check fuel pressure - again - which passed before and after the new fuel pump, filter, and pressure regulator. Maybe I have a leaky in injector but then how did if pass high idle before but not now? If I had an AFM issue I'd expect that to impact both banks similarly as would any of the other global sensors vs. a large disparity bank to bank. Compression was damn perfect as of spring this year, hard to believe that tanked in only a few thousand miles...
Frank
