98 Q45 no good deed goes un-punished

[DougQ45]

In an effort to save my golfing buddy some money, I replaced the spark plugs and valve cover gaskets on his 1998 one owner Q45 with 135,000 miles as the local stealership service dept. wanted$1,200. I thought I would really do him right and also replaced: drive belts, water pump, thermostat, radiator caps, radiator hoses, fan blade, radiator cleanout etc….to make the car go another 100,000. I also did the plugs and leaky valve cover gaskets on consecutive weekends starting with the passenger side which went fine.
However, after the drivers’ side was done, the check engine light came on. The car runs great with no issues, plenty of smooth power, no vibration, during accel. and decal. However CEL codes PO161 (O2 sensor bank 2 sensor 2) PO335 (crank position sensor A circuit) and PO330 (knock sensor 2 circuit, bank 2) all appear. So I replaced the crank position sensor as I thought O2 sensors and knock sensors are not supposed to trigger the check engine light, and that would get the light to go off? The knock sensors and O2 sensors are original to the car, per my golfing buddy. I sure don’t want to replace the knock sensor.
After re-setting the codes, the light will stay off for exactly one trip until the engine is switched off, and upon first re-start the CEL comes back on with the same codes. Again, car runs great during this. This happened 3 times consecutive, so something is amiss.
I have read on this forum that CEL codes are electrical related …is it possible that the connections near the back of the engine on top of the valve cover were bent/ damaged/corrupted during the valve cover removal when they were unplugged, and that is the reason for the CEL (i.ecould it be the codes all coming from the same plug-in connector?) Any assistance on where to start is appreciated from this fantastic forum. My golfing buddy joked maybe some black electrical tape over the CEL, but that would just not be right.

[AZhitman]

Sounds like a connection got jostled or a wire pinched in the process...

Wes should have some good insight on this, let me page him for ya.

[elwesso]

You really have (3) separate issues.. The knock sensors will NOT throw a CEL, however the CPS and o2 sensors WILL. So, there's a really good possibility that the knock sensor code was already there even before you did any of the work. Knock sensors are a common issue regardless of the year of Nissan (as they all use the same sensor), however on the V8s (and V6's for that matter) they're kind of tricky to replace. Fortunately it's possible to replace the KS without removing the plenum on the second gen Q. Replacing the KS will have a huge impact on the power output of the car (like at least 50HP).

I would personally try replacing the rear o2 sensor and seeing if at least that code goes away. If it doesn't then you know it's a connection. Another thing you could try if the harnesses have enough extra slack in them is switch the connectors from the left side to the right side.. If the code switches side (from bank 2 to bank 1), then you know the sensor is bad, and all you gotta do is replace it.

The crank sensor is a little perplexing, I believe the connector is within striking range of the valve covers. So you replaced the sensor and you're still getting an issue? That's definitely something electrical in nature, I'd double check the connection. A little trick I've used in the past for bad connections is to take some pliers and bend the pins just a little bit so that it contacts a little tighter.

[STLQ]

Did u ever find the solution to your problem?