Cam and crank sensor issue on cat motor

Glad to see you are making some forward progress.
It’s much easier and more accurate to have someone put a socket on the crank balancer bolt and turn it slowly while you look in the hole with a light.
Also not sure if You did but you should check both crank sensor and cam sensor holes for issues.

 

I hear you
I’m much the same way

 

Little bit of an old thread I know but. I just bought a new engine wire harness for my 6nz. Was only 347$ from my peterbilt dealer. I expected much more $$. Having an intermittent problem and thought for 347 ilI' just throw a new harness on first

 

I had CEL for atmospheric pressure about a year ago, changed the sensor still CEL. Ignored the light till few weeks ago. Truck would start, almost die and then be good. So knew crank or cam sensor fault. For the small price of harness and new cam and crank sensors I just replaced em all. Figured I'd be time ahead to just replace rather than diagnose, all we're original and seen some miles. No CEL anymore!! Harness definitely had some bad spots right at the ECM the plastic cover for the main connector there had rubbed some wires pretty good..

 

I had a stumble at start on my 6NZ . Replaced both sensors now its perfect EXCEPT for a small oil leak on crank sensor. I've taken it out 3 times and made sure area is as clean as I can get it and its tight. My question is am I missing something? Is it supposed to have an O ring on the flat surface that goes against the block ? It didnt come with it and old one dosen't but I can't explain the oil coming from around it..

 

Should have o-ring, PN 203-3940.

 

Is that the small one about mid section of sensor or another to help seal it? Cat says only mid sensor I call BS...

 

Just the one midway. What kind of lube did you use on o-ring.