Weird drivability problem

CNH-320 · May 27

I was driving my 2007.5 2500hd 6.0, it’s a non-daily driven truck and it stated bucking when shifting to 3rd gear and 2nd I think. After a while I noticed the tach was at 0 rpm. I got a p0336 and P0011.

My first thought was the trans was toast because it has a mild 2-3 shift flare and mild delayed engagement into D and R.

I restarted it and the tach started working again, then I ran out of time to diagnose it. Cleared codes and looked through alldata trying to get some ideas.

A week after all this happened I drove it to work, about 30 minutes, mostly highway. Ran 100%. When I started it to leave work that day it had the P0011 and b2s1 lean code, p0174 I think. About 10 mins into the drive home it started bucking a little, then more and that’s when the tach dropped to zero, Also zero rpm on the data stream and p0336 set. Also about this time the b2s1 fuel trim went to like steady 28 from being dancing around 0 the whole time. The truck ran kinda bad, bucking on acceleration and shifting until I shut it off to get some lunch. On the restart, I got the tach back and it ran fine for a bit but then back to the same symptoms till I got home. I drove it the next day into town and back, ran 100%. Seems to only do it when it’s been driven a while.

Does anyone know if this is a common issue with these trucks? I’m not sure where to start on this one. Are there any common places the harness gets worn through or common bad grounds?

I’m hoping for some good tips as my time is very limited lately due to my newborn.

I used to be a tech years ago so I have a decent understanding of most problems but I’ve been out of the game since 2009 so I’m a little rusty on diag problems.

Engine has low oil pressure, I’m pretty sure it’s the cam bearings because I’ve replaced almost everything else, including the vvt cam sprocket thing and the cam bolt (vvt valve), torque to spec. I just changed the oil, I switched to Mobil 1 5w40 with a qt of Lucas.

I undercoated with nhou last summer. It’s also my plow truck but doesn’t see much use anymore.

This is posted in the 2500hd section too, one thing I forgot to mention is the oil pressure. It’s low and will make the dinger go off at hot idle. Been that way for years the previous owner told me, so the sensor was unplugged. To make it so I could get a pressure reading, I relocated the oil pressure sensor to the port next to the oil pump, that port reads higher pressure so no more dinger. I was thinking maybe the computer thinks it has more oil pressure than it actually does which is screwing with the vvt somehow.

Thanks for your time,

asilverblazer · May 27

Start with locating the crankshaft and camshaft position sensors (P0336 and P0011). Look for wiring damage, if it isn't a daily driver suspect rodent damage.

Ignore the fuel trims and P0174 until the P0336 and P0011 are resolved.

Given that there isn't a clear signal from the crankshaft and or cam shaft position, the truck likely doesn't know what to do with the VVT/cam shaft. I would first focus on the crankshaft position sensor, this might clean up the cam shaft position.

Conversely, if the low oil pressure is indeed due to poor cam shaft bearings, those bearings might now be worn so much that they are allowing too much play causing the cam shaft position sensor to read all sorts of incorrect 'positions'.

Otherwise, the oil pressure is not part of the problem at hand.

CNH-320 · May 27

Thanks for the input. I’m definitely going to start with a good visual inspection of those sensor harnesses and grounds. I’m trying to get my hands on a better scanner too. If I get it figured out I’ll definitely follow up on this thread.

CNH-320 · June 3

I removed the starter and crank sensor to inspect. Someone I know talked me into throwing in a new crank sensor, so I got an ac delco sensor from the dealer. I busted as much rust as possible from the crank sensor socket on the block and installed the new one. I took the same route to work and back today and had no surging/ bucking issues and no P0336. I’m hoping that issue is fixed.
I almost immediately did get the P0011 cam actuator code and I’ll further diag that soon. I also got a bunch of b2s1 codes, I’m picking up a denso O2s tomorrow and I’ll install it soon.