Assistance requested with 08 Audi A4 2.0t FSI

[xero_gto]

Hello,

I hate for my first post to be a cry for help, but I have been searching everywhere, and have yet to find my exact problem. A year ago I changed the timing belt, tensioner, roller, water pump, therm, and CTS on my wife's Audi. It ran great for a year until Thursday morning when she called me and said it was acting funny. The car was idling very rough, surging up and down between 600-1200 rpm, there was also a code which tripped (P0016) Bank 1 CMP Sensor (G40)/Engine Speed Sensor (G28): Incorrect Correlation. After searching around for that it pointed to the timing belt or the chain on the back of the engine. This morning I went ahead and cleared the code and drove the car around with live data going to see if I can see exactaly when the code tripped, but that never happened. The car drove find, never missed a beat. I came back parked it and pulled the upper timing belt cover to see what the belt looked like. I noticed that the belt felt a bit loose and the tensioner was not lined up with the notch as it states in the Bently manual. I had my wife turn the car over so I could remember the direction of rotation, and after she did, the bet was tight again, but the tensioner was still not in the notch correctly. Now, thoroughly confused I started the car and checked the tensioner. While the car is running, the tensioner is aligned in the notch, but once the car is off, it's not aligned anymore. Does anyone have any experience with this? Is my tensioner bad? I have ever heard of a belt being loose, and then tight; nor have I seen a tensioner be correct running and not when its off.

[xero_gto]

I also rechecked the timing marks at the crank/cam and they looked lined up to me. Course I don't have the bumper off and the car set into maintenance mode; plus I haven't pulled the #1 spark plug to verify its at TDC.

[RakkCity]

Could be a bad sensor, if you cleared the codes and it went away it's probably not timing related, those tend to stick around through code wipes.


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[drmonkey]

I've actually been having this exact same problem with my 08. From what I've gathered it more than likely has something to do with the Camshaft adjuster or N205 valve on the back of the engine...but I am curious about the part where you said the tensioner "moves".

[xero_gto]

I pulled the upper timing cover and put a mirror down where the tensioner is, I noticed that it moves all over the place from being centered in the notch per the manual, and then over by a notch either tight or lose. It boggles my mind that a tensioner would do that, wonder if the cam adjuster in the back is causing that? Have you by chance got a P0016 code yet?

[pezgoon]

The cam adjuster in the back shouldn't as it's hydraulic whereas the one in the front is not if I'm not mistaken, Every spring powered tensioner I've ever seen "wobbles" back and forth all though I'm not sure if it should for the timing belt


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[drmonkey]

I pulled the upper timing cover and put a mirror down where the tensioner is, I noticed that it moves all over the place from being centered in the notch per the manual, and then over by a notch either tight or lose. It boggles my mind that a tensioner would do that, wonder if the cam adjuster in the back is causing that? Have you by chance got a P0016 code yet?

Yeah, I get a P0016 whenever I start driving hard...if I just drive normal then I don't get the code.

The cam adjuster in the back shouldn't as it's hydraulic whereas the one in the front is not if I'm not mistaken, Every spring powered tensioner I've ever seen "wobbles" back and forth all though I'm not sure if it should for the timing belt

The Cam adjuster is the part that you take off (using a polydrive) to get the chain off, that's the part I'm referring to.

[pezgoon]

Ohh yes I know what your talking about I forgot that is called an adjuster I think of it more as a gear my bad my bad lol


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[xero_gto]

Yeah, I get a P0016 whenever I start driving hard...if I just drive normal then I don't get the code.



The Cam adjuster is the part that you take off (using a polydrive) to get the chain off, that's the part I'm referring to.

Have you already tried to change the adjuster? I bought the gaskets to take a look back there to see if there is any slack in the chain/broken teeth on the adjuster, but didn't want to fully commit to changing that out, yet.

I went ahead and ordered a new belt tensioner, as the one that I changed out a year ago isn't giving me a warm fuzzy.

[drmonkey]

Have you already tried to change the adjuster? I bought the gaskets to take a look back there to see if there is any slack in the chain/broken teeth on the adjuster, but didn't want to fully commit to changing that out, yet.

I went ahead and ordered a new belt tensioner, as the one that I changed out a year ago isn't giving me a warm fuzzy.

I haven't, I've been waiting to order parts and tools so I can pull the adjuster and take it apart. I need to check my n205 valve first to see if it's gone bad as that might be the source of the problem.

[xero_gto]

I haven't, I've been waiting to order parts and tools so I can pull the adjuster and take it apart. I need to check my n205 valve first to see if it's gone bad as that might be the source of the problem.

I'm pulling my stuff this weekend, I'll let you know if I find anything unusual; hopefully I don't need to change out that adjuster or tensioner.

[Charles.waite]

I would pull the front end off and reset the proper tension on the timing belt tensioner. Make sure its set properly then move on to other possible causes. Yea its a decent amount of work, but replacing a head is a lot more...

[xero_gto]

I would pull the front end off and reset the proper tension on the timing belt tensioner. Make sure its set properly then move on to other possible causes. Yea its a decent amount of work, but replacing a head is a lot more...

I agree completely! I am going to put a new belt tensioner on, and just check out the rear cam chain/tensioner to make sure everything looks kosher back there.

[drmonkey]

I would pull the front end off and reset the proper tension on the timing belt tensioner. Make sure its set properly then move on to other possible causes. Yea its a decent amount of work, but replacing a head is a lot more...

Even if it's not skipping a tooth could a loose tensioner be the culprit? I've had the timing checked and verified and it's spot on.

[Charles.waite]

Even if it's not skipping a tooth could a loose tensioner be the culprit? I've had the timing checked and verified and it's spot on.

Could be for sure. Slack in the chain would screw up the variable timing mechanism.

If the timing is good and the tensioner is tensioned properly I would move on to the chain tensioner.

[drmonkey]

Could be for sure. Slack in the chain would screw up the variable timing mechanism.

If the timing is good and the tensioner is tensioned properly I would move on to the chain tensioner.

I thought we were talking about the timing belt tensioner? I know the chain tensioner can cause issues.

[xero_gto]

I thought we were talking about the timing belt tensioner? I know the chain tensioner can cause issues.

I am talking about the belt tensioner. I have yet to determine the status of the chain/tensioner. I could see how a wonky belt tensioner could throw off the hydraulic cam adjuster, which is why I am going to try to do that first. The timing looks good to me, but I am going to double check the timing (both marks lined up and #1 TDC) before I pull the old tensioner off.

[Charles.waite]

Oh shoot I misread. Yea a loose belt tensioner could definitely be causing the issues. Because it's causing the crank and the cams to be out of sync with each other.

The hydraulic chain adjuster only changes the relative timing of the intake and exhaust cams. A loose belt would make them both off by an equal amount and probably wouldnt mess with the timing/chain adjuster too much.

[xero_gto]

Oh shoot I misread. Yea a loose belt tensioner could definitely be causing the issues. Because it's causing the crank and the cams to be out of sync with each other.

The hydraulic chain adjuster only changes the relative timing of the intake and exhaust cams. A loose belt would make them both off by an equal amount and probably wouldnt mess with the timing/chain adjuster too much.

I hope this is the issue. I am just going to check the chain/tensioner to be better safe than sorry. I still think this belt tensioner is what threw that code, but we'll see once I dig into it.

[drmonkey]

Oh shoot I misread. Yea a loose belt tensioner could definitely be causing the issues. Because it's causing the crank and the cams to be out of sync with each other.

The hydraulic chain adjuster only changes the relative timing of the intake and exhaust cams. A loose belt would make them both off by an equal amount and probably wouldnt mess with the timing/chain adjuster too much.

Ah, that makes a lot of sense. When I did my timing belt, the new tensioner I received broke and so I had to re-use my old one (the spring and the bearings felt fine and no different than the new one). I might replace that just for peace of mind.

On the other hand, I pulled the plug off the n205 valve and got a nice flood of oil out of it so I'm pretty sure that's my source of the problem.