I got a replacement (Gates VVT sprocket). I replaced it this yesterday. The "over-advanced" problem is gone but Im back to the original P0016 code.. GRRRR!!!!

I have recently replaced the VVT solenoid(before doing the chain), the cam position sensor last year in this troubleshooting saga(I striped these from another block being tossed so they worked).

Still, it runs fine, I no longer feel a drop when I turn the AC on since replacing the chain- before I could feel more vibration and RPM drop a hair when ac is on.

I wonder if running the corelation would fix it...
I'm tempted to cry uncle and have a shop hook up a computer to tell me if it is physically not synching\what is not synchning or working properly.

btw, I use Valvoline 5w30

TIA.

 

OK on your oil. Valvoline 5w30 is a very good oil.

Have you tested the camshaft position sensor? Here is an article on how to test it:

https://troubleshootmyvehicle.com/gm...p-sensor-tests

Good Luck!

 

Crying uncle, I went to a shop yesterday. They say they tested everything- VVT, Crank sensor, Cam sensor, etc. They tell me everything works, that they need to open it up.
They may be right- the VVT sprocket that I replaced was bad registering Over-advance(or something like it) that I mentioned earlier. Being I replaced it without taking the whole engine apart, maybe it did skip the crank tooth after all.
I 'm debating cheat\gamble and advance the chain 1 tooth on the cam sprockets vs taking the whole thing apart again.

Thx.

 

I think the most likely cause is the chain jumped a tooth, regardless of how it may have happened. If not a jumped chain, another mechanical cause, such as oil leaking past the control solenoid when it shouldn’t be.

These codes (Crank to cam correlation) are, generally speaking, dependable for knowing it’s a mechanical problem provided there’s no other codes set such as a cam or crank sensor performance/circuit code.

The quickest way to isolate the fault is by scoping the crank and cam patterns at the same time with a multi-channel scope. The overlay of the signals with the VVT disabled will tell you immediately if the cam and crank are synchronized.

I’ll do some more digging when I have time but here’s some screen shots of service information (tried to keep them in order )

 

Ok. to avoid removing the whole cover, I wedged the tensioner and moved the sprockets forward 1 tooth and that fixed the immediate check engine code.

I bring up Jurasic Park(falling jeep lands on top of them) because I'm back to the original code - "P0014 Exhaust cam position timing - over - advanced". I got this only when decelerating as I didn't get this code driving on the highway for an hour only for it to appear when I slow down.

I just replaced the VVT sprocket I just bought- also getting a different brand(Gates). So 2 different new, different brand VVT sprocket, same code????

What do you I should do now? Get a different VVT solenoid? As I tried that already when I first got this code...should I try an OEM solenoid??, or go back to the original (old) GM sprocket???

Or do you think this is a engine computer issue???

TIA.

 

This further suggests that the cause is most likely a jumped chain.

I understand you don’t want to pull the front cover again but this will probably continue happening until you visually verify the timing marks are correctly aligned.

 

Well, it has been 1 week so far, code still gone. I ended up reinstalling the original VVT last week. So 2 VVT sprockets that don't work quite right I guess...

 

Thanks for the update - hopefully you got lucky.

 

Since you did a thorough job with the chain repair, it's more likely that there's a small alignment problem, a bad part in the VVT system, or an issue with the oil that's causing the trouble code. It's usually better to check these things first before thinking about more complex repairs.