# Running rich and lean - please help



## velere54 (Dec 30, 2014)

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?


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