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Discussion Starter #1
After putting in a new camshaft (I'll tell why later), it started with difficulty but ran well at 2K rpm for recommended 30 minute break-in. But it continued to have difficult start and had no power with any kind of upslope. VCDS says cam position sensor sends incomprehensible signal. I see where it is, can it be changed without going back to the service position, and without taking timing belt off?

Thanks
 

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Did you try clearing the code and seeing if it returns? Are you sure the camshaft was put in correctly and the timing belt isn't off? It's right below the camshaft sprocket but I don't know where the other end is. Maybe a wire is chafing or got nicked.
 

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It should be able to come off as is. Here's a pic from the timing belt article where you can see the camshaft sensor at about the 4 o'clock position.


The other end of the wire goes in the harness underneath the fuel filter bracket. Refer to the fuel filter article for how to remove it. I don't remember where the plug end is though. Here's a pic of the wire, yellow arrow. If you could take plenty of pics of removal it would much appreciated :) And if you write it up it would be entered in the bi monthly contest for writeups.

I don't have clear pics of the wire highlighted below, the plug end, and of how to remove the sensor.
 

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Discussion Starter #6
Sorry, I'm not much good at posting pics, but starting with yours, it should be easy to follow:

1. Identify cam sensor at 4 o'clock from cam sprocket, then see rubber dust cap below that. Push dust cap rearward and catch it on other side. Remove 10mm bolt (don't drop it). Sensor will fit through hole.

2. Remove fuel filter per your write-up, then remove filter bracket-3 bolts and 1 nut. Watchout for dipstick!!

3. Follow the gray cord, cut small harnesses. Under the filter bracket is another harness that can be opened and re-used. Cut two more small harness ties working toward the firewall. On the firewall are three plugs, this one is farthest to drivers side.
 

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To qualify for the contest it needs lots of detailed pictures showing how to do it. Thanks for the tips though, I forgot which connector it was. Thanks for any follow up if it was indeed the problem.
 

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Discussion Starter #8
In my quest to get a smoother idle vibration, I replaced my cam with a Colt Cam regrind, plus new lifters.

A little difficult to start, but ran it half hour at 2Krpm for break-in and felt smooth. Drained and changed the oil. Still a little difficult to start but then would get smoothly to 5Krpm. The idle was rougher than before, and maybe a little slower.

Tried to drive it, but no power going up driveway or the street, felt good downhill.

Frank's Vagcom said "cam position sensor implausible intermittent". Torsion value 0.0. I bought a new sensor, no difference.

So, could it be the cam, the sensor, the wiring, the cam sprocket? I have never had a starting problem before. I have double checked all charge air connections, and all electrical plugs in the engine compartment are plugged in. I would like to have a decent idea before putting the old cam back in.

It does the same if sensor is unplugged

Thanks.
 

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If you are having problems getting the cam sensor to read, there is a very good chance your cam is a tooth off. Re-pin everything and double check it. I hate to admit to it but I have had this problem, car would start sometimes and run rough, sometimes randomly die. The torsion value read 0.0 all the time and have the implausible signal code. If the cam is a tooth off the sensor will not recognize the signal. The ecu defaults to a 0.0 timing reference, but since the cam timing is off it will run poorly since all the fuel timing is based off of the 0.0 default.

The cam sensor is more than likely perfectly fine. I replaced mine with a good used one, problem remained, installed a brand new sensor, problem remained. Pulled covers and re-pinned cam and crank and found the cam to be 1 tooth retarded, somehow I got the crank lock on in the wrong place. Reset the belt and have been fine every since.

Good luck
O.C.
 

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Discussion Starter #10
That makes perfect sense, I will check it again tomorrow. I thought I was so careful, and with the metalnerd tool, you shouldn't be off. But that is the place to look. I will report after.
 

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All's well in Mudville. First, humble pie, I mistimed the engine by one tooth I guess. Thank you OCTDI for that tip. After correcting that, and then spying the vacuum hose that came off the N75, it was fine. Timed to 2.9 deg advanced.

I now have a ColtCam BHW stage II cam and it accelerates better than ever! Lots of fun to drive.

I probably won't get full satisfaction on getting less vibration at idle; it is about the same. I can live with it, but one simple adjustment that would help cannot be done as far as I know. That is raising the idle speed about 50rpm. My car idles at 861rpm, and if I manually raise it, it feels better. Is there a trick to use on Vagcom?
 

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It's always good to keep on learnin'.

For example I now know that you can't change timing on PD motors, just the cam-crank relationship. When I can borrow Vagcom again, I will put the torsion # at 0 to +.5. I want to see how much it affects idle compared to 2.9
 

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Cam sprocket

I have similar problem. My car was cambelted abaut a year ago. I bought it a month ago, so i started do some little works on it. I noticed car had a rough idle, so checked it with vcds. And it came out synchro angle was -3.3 then i had to set for -7.7 and the car idle right now. Basacly i think someone put the cam sprocket back to the wrong angle or jumped a tooth or 2. Im not sure. Is there anyone able tell me how to set the camsprocket back, otherwise i never gonna get the right angle for the timing.
 
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