P0016 code

Hello I just joined today, looking forward to becoming a part of the community.
2004 4.3l Silverado, throwing a P0016 code. I have pulled the distributor and the gear looks fine and no slop in bearings. New cam sensor, made no difference, the crank sensor is covered in oil. This truck was doing this before and the owner had a timing chain installed, it ran good for a couple weeks and now the code is back, I became involved, checked codes and P0016 is showing along with random misfire. One guy told me the P0016 tells me the sensors are good just not in time. I'm a old school mechanic so I'm learning, I would appreciate any ideas, thank you.

Hey Michael! Welcome to the community.

A scan tool with the ability to view OE data will be key with this code. You're looking for the CMP Retard PID. It'll keep track of how far the CMP sensor is out of time, and in which direction. Without that data PID, you're kinda out to sea. :silly: You either have to use a dual channel lab scope, or just adjust the distributor and hope the code goes away.

This code will set if the CMP Retard PID reads too far advanced or retarded. I don't have the code set criteria in front of me, but it's usually over 15 degrees +/-. Really, if the timing chains are good, the distributor is stabbed correctly and adjusted, the reading will be within two degrees of zero.

While you're doing your diagnosing, remember that the CMP Retard PID only updates when the engine is revved over 1000 RPM. That means if you do an adjustment, you have to rev the engine to see the change.

This SD video may give you a better idea of the problem, if you haven't seen it already: