cam tensioner - 1.8
 

I put a 1.8 into my D2 last week and having a problem...

No, I didn't do that but I am doing a job for a friend on a 2001 A4 1.8T. I'm getting the following code and getting a loud diesel sound from the cam tensioner area. I didn't want to run it for long. I pulled the valve cover and was expecting (hoping actually) to see a broken tensioner pad. The top one looks fine, the bottom looks ok from what I can see which isn't much.

Where the engine stopped, the cam chain does have tension on it. All things point to a bad tensioner but I thought they only made this loud noise when the pads broke? Maybe the bottom one is so I'll probably pull the whole thing out. The car has 140k on it and has had amazing maintenance... the inside of the engine looks brand new.

Any thoughts?

16395 - Bank 1: Camshaft A (Intake): Retard Setpoint not Reached (Over-Advanced)
P0011 - 35-10 - - - Intermittent

Here's the ironic part of the story. He drove the car down for me to change the valve cover and tensioner gaskets. As he literally got to the end of my driveway that's when the noise started. If he had gotten to my house one minute earlier.... this would have been my problem after changing the gaskets.


Bob

They actually chatter when oil pressure is low, or the tensioner is just plain shot internally. Given the code you definately need a new tensioner.

tensioner
 

ok, got it. I thought they made the diesel sound when one of the pads broke. New one is on the way.

thanks

Bob,

You got me...I was already composing a "why the hell would you DO that?" response in my head :)

Just a theory, based on what happens with ignition timing over-advancement, which causes actual dieseling (pinging wrist pins): You might be hearing that from the engine, not the adjuster (tight chain should be quiet with pads intact)...BUT caused by the adjuster's over-advancement. I'll bet it probably runs perfectly at high rpm.

If the adjuster is stuck in full advance position (top pad fully extended upward, lower pad drawn in to bottom of adjuster fully) , could be one of 3 things:
1 - Actual stuck adjuster piston
2 - Solenoid stuck/faulty
3 - Incorrect signal to solenoid

You probably already are, but I'd go through the same checks as you did with your 4.2.

All theory of course, lookin at it from a 4.2 point of view.

Curious to see what you find.

Cheers,
Sam

cam marks
 

Sam,

I'm about to pull the tensioner now and hopefully will "see" something but as auditech posted, it could be a hydraulic issue which would make sense. He drove on the highway here and it was fine. When he idled down in the driveway is when the problem started - low pressure.

How close are you guys finding the cam and cam cap marks line up? On this car, the closest I can get the arrows (on the cam caps) is to at the inside edge of each "notch" mark on the cams. 16 links on the chain in between.

I've seen this a few times now, it seems like the marks are really more of a "range" and not always dead center.

Do you guys agree?

I agree...a full tooth off (chain or belt) would likely be way off the mark completely.

Just a working theory:
My guess at something stuck or a control problem, rather than a "low pressure sensitive" problem, is based on what little I understand about the adjuster's operation.
Looks like low pressure or no pressure, would more likely lead to the retarded position of the adjuster...pressure being required (I think) to achieve the advanced setting. Even a solenoid not actuating would (again, I think) leave it's valve set to the retarded position.
Higher rpm (highway driving) would be a naturally more advanced setting for ignition and cam, so if it was stuck in the advanced position (whether by piston stuck, solenoid stuck or false control signal) it would not be as much of a problem or even noticeable until dropping to idle or parking lot rolling speed.
Just brain stormin a little for fun.

Attachment 33600

The tensioners on 1.8Ts can stick in either retarded or advanced position, whether is the solinoid or piston i don't know, we usually just threw them away or sent them in for warranty purposes. It would be cool to see whats exactly wrong with this one as i've never cracked one open to see.
However i have heard from audi that the oil supply/return can get plugged/blocked which also results in the tensioner failing. Im guessing by your diagrams that this would cause it to lock in the retarded position, so he most likely has a stuck solinoid or piston.

That reminds me, seafoaming the engine would also be a good idea as 1.8T engines are notorious for sludge. I should also say that the new tensioner can chatter for the first couple hours of operation on a 1.8, this is most likely due to break in and the design of the oil pump/pick up design, which is faulty IMO.