OK, so a few months back I bought a 02 a6 2.7 with 185k for pretty much scrap price, had a blown turbo and some cosmetic issues. Pulled the motor and figured "while it's out, let's do a rebuild, what could go wrong?"

Everything went fine until I fired it up and got a g163 implausible signal, OK so I probably muffed the timing since I used a piece of cardboard to align the cams. Bought a cam lock bar and followed instructions to the T minus the crank lock pin, I just made sure the marks were lined up before I torqued the cam sprockets down.

Still the same code, swapped crank sensors and still the code is on bank two. Pulled both valve covers and checked timing using the diagram on Ross techs website. Still, same code.

Found a crack in the insulation of the g163 pigtail, replaced it with a good one, still same code. I get good ground at the sensor, 5.01v on one pin and 12.4v on the other pin.

I'm completely out of ideas, timing on both banks cams have been checked 3 times, crank to cam about 4 times and sensors checked, I'll literally PayPal the winning solution $15 if it fixes it.

 

Probably the crank is off alignment. These V6s are notoriously finicky with the timing belt alignment. You have to pretension the belt with the sprockets loose and the crank locked in place. Then tighten the sprockets.

 

yes, timing belt was done correctly

 

Without the crank lock pin? I beg to disagree.

 

To elaborate, in order to get the timing right, you need to align 3 points; both bank cams and the crank. If during the 1st attempt if the crank was misaligned from the cams, aligning the cams on the second attempt wouldn't solve the crank misalignment.

 

Even if somehow my timing mark on the crank is off a few degrees, wouldn't it throw a code on g40 too?

Also, I know there's a bit of timing misinformation, something about Bentley or another company that tells you the incorrect amount of chain teeth. This is the correct diagram to go off of correct?

http://wiki.ross-tech.com/wiki/images/thumb/1/16/Cam_timing_chains.gif/200px-Cam_timing_chains.gif

 

First of all, I wouldn't worry about the timing chain. You did not touch it, so there is nothing to worry about. From my experience in wrenching, 99.9% of the time, it is something that I touched. Not something else.

Back to the pulley mark and the dimple of the lower timing belt cover... It is intended to be for visual reference only. Sometimes the harmonic balancer integral to the pulley can slip with age. So the only true way to get it right is to open up the crank lock pin hole, put in a screw driver to feel for the crank dimple to line up, and to lock the crank with the pin.

 

did a full rebuild on the motor, valve seals and chain tensioners included, cams were indeed out of the head, gonna go use a cam lock pin, will report back if it continues to give me the timing code

update: pulled cyl. 3 spark plug, used the dowel method, timing marks on harmonic balancer line up perfectly to the ones on the timing cover. popped the lock pin in, seemed to slide in fine, cant rotate the crank either direction, cam lock bar slides right into both sprockets. pretty much settled it down to intake < exhaust cam timing. pulling vc cover off to check the timing for the 4th time now, will post pictures this time

 

Sorry did not realize that you did all that. On that note, go read this.

https://www.audiforums.com/forum/aud...-a6-up-174154/

 

Still having this issue, I took both valve covers off, disconnected the injectors and cranked it and saw bank 2 timing chain tensioner was bouncing with every rotation, so maybe I got a bad tensioner. Replaced the tensioner and repeated. The bouncing went away so I patched it up and started it, still the same code pops up.

so far:
Crank TDC (confirmed with lock pin, timing mark and dowel method)

Cams to crank, lock bar used and proper method for belt tension used.

Cam to Cam, I've counted chain links more times than I'd like, both banks are timing correctly.

Cam position sensors and the cones on the end of the cams checked

Got good ground and voltage at the sensor pigtail

I'm pretty much spent, the only thing I can think of is my timing belt is stretched or my timing chain is stretched but they would have thrown the codes prior to the rebuild.