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.

 

Never checked the cam hole becuase the truck would run without the crank sensor plugged in and start normal. But I’ll check that one as well. Hard to get a second hand to help do things with my truck. I’m the type of guy that hates to call someone over for help

 

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

 

When I first started having this issue I changed the harness out inside the motor. It was like 250 bucks. Then I had still had this issue with the cam and crank sensor. Fixed a few wires and everything was checking out ohm wise. I was told new main cat harness was big bucks. Fortunately, these harness are very inexpensive for our cats. I got mine for around the same price as you paid from peterbilt. Cat wanted a few bucks more and they got the harness from cat. Weird. Anyhow, hooked her up and had a buddy clear all the old codes and all is good. I took apart the other harness just for the hell of it and it was in bad shape with oil that seeped in and etc.
if you ever get jake or injector fault codes, make sure you change out internal harness. It can be done without removing the jakes. Just have to undo a few tabs with a long screw driver and fish the harness where it needs to be. My old harness was leaking oil from inside valve covers through the wires themselves down into the main engine harness. If yours is doing that, it’s time for a new harness in there

 

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.