I have an 08 Silverado with a 5.3L. just rebuilt the motor after the DOD seized up the intake lifter on cylinder four. During the rebuild my friend advanced the timing gear two degrees and I've always thought the timing was all in the computer? After the rebuild a cam position sensor popped up and I replaced it and it popped right back up. Am I right in the timing being electronic or is ok that it is and it's a tuning issue

 

When you advance or retard the camshaft it's a valve timing event not a spark event, It effects where the cam makes peak torque and horsepower. Your issue lies somewhere else.

EFFECTS OF ALTERING CAMSHAFT TIMING

Is the issue popping up immediately or did they fail over a certain amount of time? Did it throw a check engine code?
If you had it apart it could be a wiring issue.

 

There's two types of timing

Cam timing and Ignition timing.

You can alter the cam timing to give different performance of the engine, it will usually change if the engine makes more power up high or down low. Advancing the cam makes it make more power down low which is good for a truck.

I do not know if advancing it two degrees is enough to set a timing error code, it may be, it may need to be tuned. I imagine it will set a code since the computer is seeing the advance in the cam timing. Tuning should take care of that.

 

How did he advance the timing...with something like this??

 

I was wondering the same thing, it doesnt seem to be a very common thing for a fairly stock build.

 

It's not uncommon for trucks since they need low end grunt and it helps when towing. It still wouldn't explain the sensor failing.

 

It may not be a sensor failing code, it may be a cam/crank correlation code since the pcm is seeing a difference in the cam position. In a stock setting if it sees the cam move it will throw a code for the timing being off. Not sure exactly which code it will throw or exactly which one he is getting but the computer don't like it when the cam moves

 

That's why I asked if it threw a code, I assumed it was a bad sensor but you never know how the person on the other end of the conversation is getting that info.
I know most cams can be bought with the advanced ground in but what's the point of all the companies selling adjustable timing sets for an LS engine if it's going to throw a code for only a 2 degree adjustment?

 

Because tunes

Same reason they sell off road y pipes that will set a code, big cams that will set a code.... the list goes on and on. Performance parts and modifications aren't made to bolt on and go. Cmon man you know this!! lol

And to be fair about the cam timing thing, when advance is ground in it keeps the tone ring of the cam in the same place so the PCM doesn't see a change in timing, but the valve events do. Advance really should be done that way. But if you advance a cam by using the timing set the PCM is going to see it and that technically puts the timing out of parameters since it doesn't expect to see the cam there. It thinks it's a tooth off, or has a stretched chain etc.

 

I understand how it all works I didn't know that the advancing the cam +- 2* would be enough to throw a code, I've replaced plenty of timing chains that would have likely been that far off and never threw a code. I have little experience with HP tuners and it will likely stay that way since I use Holley EFI for everything of my own and I don't have any interest in tuning anyone else's junk unless it's running the Holley system or a carb lol

OP hasn't been back since he posted so we may never know it was actually a sensor failure or not, I know just because it's a new sensor doesn't mean it's a good sensor, I chased my tail while replacing a bad crank sensor recently when the new one from Autozone was bad and so was the second new one. I finally got smart and took one from another engine that I knew was good and tried it before tearing the harness apart.

 

I hear ya, and you may be right. I'm just speculating and saying it's possible. I don't know what the tolerance level is.

But there's also the possibility of stacked timing too. So if he did a new chain and gears, and a timing set that weren't 100% spot on he could have more than 2 degrees. But again, it's all speculation because I don't know what the tolerance is in the OE programming for timing variance. I do know that they are fairly sensitive and I have late models come in pretty frequently with cam timing correlation codes due to customers either going far over an oil change or being a little low on oil or both. I assume if it will trigger a code from low or old oil then making an actual physical change in the timing could be enough.

Who knows man, all he said is he did a cam then had a cam sensor issue so I assumed it was an error code issue because how do you do a cam and take out a sensor?

Your statement about new parts not being good... I'm a tech and have been over 20 years, you're damn right about it never being a guarantee. I've had that happen many times and I see many tech get caught up in "it's new it has to be good".. don't bet on it.