I have a 2001 Audi S4 on which I recently changed the timing belt and cam seals. I had to remove the cams to access the seals and ever since the TB job I get a CEL. The description of the codes is as follows:


16730 - Camshaft Position Sensor (G163): Implausible Signal
P0346 - 35-00 - -

16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - Please Register/Activate

16690 - Cyl.6 Misfire Detected
P0306 - 35-00 - Please Register/Activate

16689 - Cylinder 5 Misfire Detected
P0305 - 35-00 - -

16688 - Cyl.4 Misfire Detected
P0304 - 35-00 - Please Register/Activate

I clear the codes and they continue to return. After a couple hours on the internet, I concluded (accurately?) that my problem is either i) the cam position sensor is bad , ii) the cam to cam timing is off or iii) the cam to crank timing is slightly off.

First I swapped the cam position sensors and I get the same exact problem, so the sensor doesn't seem to be the problem. Second, I pulled the passenger side valve cover and double checked the timing, which, to my shock, is correct (see photos).

Now my only other guess is that the cam to crank timing is slightly off, so my next step is to double check this timing- When I replaced the TB, I used a cam lock tool but the crank may have moved slightly by a half tooth or so. I would like to exhaust all other resources before I tear the front of the car off again. I have access to a computer with VAG com and would like to see if I can make this determination through the computer.

I am going crazy trying to get this fixed so any help/comments/feedback/slander would be appreciated.

 

Any thoughts??

 

I would check your cam to crank alignment. The cam lock bar does it's job but when releasing your tensioner pulley you should make several revolutions on the crank. Many times you'll see that slack gave you the impression you were perfectly in time.
I know it sucks but i recommend removing the bumper, cond, rad, etc and checking that your time is still where you want it.
This may be arbitrary information for you, as i doubt you have the know how to change the TB but not make several revolutions before reinstalling.
The handful of times iv'e done a TB on the 2.7 i kept the Radiator empty and started the car and let it idle and even a couple low rpm revs. Obviously you cant let it run to long like that, but your not gonna hurt anything if you don't overdue it. After some running then i double, triple check timing marks then reinstall.
I hope this helps.
Just for ***** and giggles i would swap a coil pack from a cylinder without code. If the problem follows that coil you may be dealing with 2 separate problems.
(however unlikely considering you just did the timing belt and now you have cylinder misfire)

 

Thanks for the reply. How do I make sure the crank is aligned exactly TDC?

 

There is a "tic" mark on the crank pully. Line it up, be sure your cams are perfect and you should be all set.

 

That cam is not correctly timed.

 

there is a crank locking tool that is threaded in the driver side of the block that locks the crank into TDC. But when you reinstalled the cams, did you make sure you counted 16 rollers of the cam chain inbetween the alignment marks on the cams? Make sure there is 16 roller links between the two marks on the cams.

 

cam to cam and cam to crank is the same.. if you have one cam off then it is not only off to the crank but the other bank as well, unless you are talking about exhaust and intake cams on one bank.. but seems to me that bank 2 cam is off a few teeth???maybe?? and i do agree with drev.. there is a cam locker crank locker tool for timing belts that i think everyone on this s4 site owns and has used at one point or another. its a no brainer, you have to try and get it wrong to ef it up.. recheck your work and line it up.. hopefully youve bent no valves....

 

Ok. I took my car apart this weekend and sure enough the passenger side cam was slightly off. I retimed the engine but not I am getting a different error code:

17755 - Camshaft Position Sensor 2 (G163) / Engine Speed Sensor
(G28): Incor. Correl. P1347 - 001 - Upper Limit Exceeded

I double and triple checked the timing and used a cam lock bar but still the problem persists.

I used the vag com to monitor the misfires. Previously, I would get misfires at idle but now I only get them when driving at a constant speed or decelerating at around +-3,500 rpms. I have no misfires when accelerating. I have some logs that I can post when I get a chance. I think the cam chain tensioner is bad?? Anybody else have any ideas?

Is there anything else I can check on the vag com that would give more info? Any help would be great.

 

If you had a bad cam chain tensioner you would have harcore misfires across that entire bank. There is still something wrong with the timing belt, maybe the hydraulic tensioner is shot.