Running rich and lean

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velere54
Posts: 8
Joined: Thu Jun 18, 2015 3:31 pm
Car: 2004 Maxima

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What would cause cylinder bank 2 to run rich and bank 1 to run lean.

I replaced the timing chain guide, water pump, rear main seal on my daughter’s 2002 Maxima. I marked the chains to insure I got them back in the right place. The car started up on the first crank and ran well up to 6000 rpm and 80+ mph.

The next day it started running poorly and blasting out greyish smoke. I got a couple of DTC’s, P0171 and P0300. I found that I had damaged the electrical connector on the bank 1 variable valve timing solenoid (stretched the harness too much). I fixed it and the car ran well for a couple days. Then, it started running very poorly. There were no DTC’s. I found that the bank 2 catalytic converter had disintegrated probably due to running too rich, and had plugged up the rear converter. I replaced it and cleaned the rear converter. The car started immediately and ran fine. Once again it ran fine for a day then started blasting out white/grey smoke from bank 2 only and bank 2 only is running rich. Bank 1 fuel trims are fine and no smoke. The bank 2 pre converter O2 sensor is ok. Once again, there are no DTC’s. I also removed the exhaust and the bank 2 converter is ok. My O2 sensors are functioning and I also tested Ohms and tye read ok but I went ahead and replaced the preconverter sensot anyway. I checked my camshaft position sensor ok but went ahead and replaced it. I checked for exhaust and intake leaks and found none but went ahead and redid the exhaust and intake plenum. I checked fuel pressure and it’s ok at 43 psi. I have verified the injectors aren’t leaking. Bank 1 short term trim is +6 to +10 at idle and +7 to - 5 at 2500 rpm. Bank 2 is +12 to +14 at idle and -25 at 2500 rpm.

I’m afraid to run it since running rich probably destroyed the converter the first time.

The timing must have been ok after the work I did. What could cause it to jump?

I’m pretty sure the injectors will turn out ok. What else will cause one bank to run OK and the other to run very rich?


NutriaforBreakfast
Posts: 1316
Joined: Wed Sep 26, 2007 1:41 pm
Car: Nissan Maxima 1995 VQDE engine

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How does the car sound after it is started from a COLD start? Was there a timing chain rattle?
How did you confirm Top Dead Center ?

velere54
Posts: 8
Joined: Thu Jun 18, 2015 3:31 pm
Car: 2004 Maxima

Post

The car sounds fine, no rattle. I confirmed TDC with a tape wrapped screwdriver in cylinder 1. I'm positive the timing chains and gears were all in the correct positions.

NutriaforBreakfast
Posts: 1316
Joined: Wed Sep 26, 2007 1:41 pm
Car: Nissan Maxima 1995 VQDE engine

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Have you tried adusting the valves?

EdBwoy
Moderator
Posts: 3352
Joined: Tue Dec 25, 2012 12:47 am
Location: Indiana, USA
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velere54 wrote: The timing must have been ok after the work I did. What could cause it to jump?
I'll only attempt to answer the part that I have dealt with. But low pressure is one thing that would make the timing jump. If your engine does not have adequate oil pressure (and thus the tensioner is not pressurized/ extended out) when you crank the engine for the first time, there is a possibility for the chain to jump the teeth before the tensioner catches up and tightens the chain.
...all depending on how devoid of oil the tensioner was. The spring in there does a decent job of pushing it out, but it could happen.
Hopefully your issue is much simpler.

velere54
Posts: 8
Joined: Thu Jun 18, 2015 3:31 pm
Car: 2004 Maxima

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I'm pretty sure it's not the valves since their was no issue prior to the wrk I did. Also, the chain tensioner was tight up against the chain and there was no slack and the car started up immediately on the first crank so I'm pretty sure the timing is ok.

NutriaforBreakfast
Posts: 1316
Joined: Wed Sep 26, 2007 1:41 pm
Car: Nissan Maxima 1995 VQDE engine

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White smoke is not good
Have you checked to see if there is oil in your water or water in your oil?

velere54
Posts: 8
Joined: Thu Jun 18, 2015 3:31 pm
Car: 2004 Maxima

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There is no water in water or vice versa. It's actually a grayish from bank 2 due to running rich probably.

NutriaforBreakfast
Posts: 1316
Joined: Wed Sep 26, 2007 1:41 pm
Car: Nissan Maxima 1995 VQDE engine

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What about emmissions? EGR Valve-EGRT BPT - EGR Temperature sensor-PCV - ?


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