Timing Belt Frayed

[HermTDI]

Car Info:
1989 Jetta
Eng. 1.6L NA
Engine code "ME"

Problem:
The Timing-Belt (TB) on this engine was replaced about 700 miles ago. In that time the new TB has become worn & frayed along the outter edge.

As the engine runs the TB "wonders" to the edge of the pump spocket and then down to the intermeadiate shaft sprocket where it looks like the TB is riding over the edge of this sprocket.

My question is: What is worn to cause this TB to be riding towards the edge of the sprockets. This engine is not safe to drive because the TB is badly worn (edge of the TB is frayed).

Does anyone have any experieance with this issue?

TIA
Herm

[DVST8R]

I had the exact same problem with my TD, it was an increadibly frusterating month of diagnoisys b4 i finally figured it out. I tried everything i could think of and then things that others thought of, what it ended up being is that some where along the lines the plate that holds the injection pump, the one that is on the timing belt side of the motor, not the support bracket under the pump had some how become tweeked and caused it to run off. The only solution was to replace that bracket. I tried straightning it, but it was out so little that it was hard to tell if it was straight or not.

I ended up just using another one off of a car from a junkyard and presto no more problem's this was after 3 timing belts and like a million tries. To this day I still have no idea how it got bent, or what caused it, but that is the solution.

[LeeG]

Could your injection pump be bolted on out of alignment?  

The tensioner pulley is the only one with a lip to control the drifting of the belt.  I have had 2 tensioners break such that the 2 half shells of the pulley came apart at the spot welds.  One broke so the inner shell was loose and rubbing on block, got noisy but no damage.  Other lost the outer half shell causing the belt to slide partway off, eat into the upper timing cover, make a huge racket and lotsa smoke, but I shut it down in time to avoid what was coming next.  That belt was frayed!  And yes, I suspect I was overtightening the belts, I set them up a little looser now.

[fatmobile]

I think the most common cause for this is the injection pump shaft bushing getting worn. Just because it's old or because the belt has been tightened too tight sometime in it's life.
 This causes the shaft to ride at a slight angle and the belt runs off.

[LeeG]

If pump bushings were that worn, wouldnt it also be spewing fuel out of the pump?

[HermTDI]

I had the exact same problem with my TD, it was an increadibly frusterating month of diagnoisys b4 i finally figured it out. I tried everything i could think of and then things that others thought of, what it ended up being is that some where along the lines the plate that holds the injection pump, the one that is on the timing belt side of the motor, not the support bracket under the pump had some how become tweeked and caused it to run off. The only solution was to replace that bracket. I tried straightning it, but it was out so little that it was hard to tell if it was straight or not.

I ended up just using another one off of a car from a junkyard and presto no more problem's this was after 3 timing belts and like a million tries. To this day I still have no idea how it got bent, or what caused it, but that is the solution.

Are you talking about item #4 in this ETKA excerpt?

[andy2]

I had the same problem and it was partically due to a worm inj pump bushing,Loose pump support bracket bolts(cast support to block),The loose bolts caused the other support bracket to get bent as well.

I,ve noticed that the later 1.6 and all 1.9's imtermediate pully don't have those belt fraying lips on them.If you can find one without the lips on them or take the lip off the pully that may be all you need to do.A loose timing belt will wonder a little on the intermediate pully causing it to get cut on the pullys lip.As long as the belt isn't already running off the pump sprocket,I would'nt worry about either the pump bushing or brackets

[DVST8R]

HermTDI your pic isnt working, so I can't answer that.

As for the rest of the answers or questions, My pump was fine, worked great untill that, worked great after the bracket swap, I triple checked the alignment of the botls, there tightness the tightness of the timing belt ect, I literally worked on this for a month... all to no avail. It was only once the bracket was swaped did the belt stop walking off the pulleys.

[TDForNow]

If pump bushings were that worn, wouldnt it also be spewing fuel out of the pump?

Nope, this is the suction end of the pump. If the seal went bad too, it would start sucking air there, noticable by hard/rough starts after setting a little. With just a worn bushing as stated before, the pump shaft/pully will be pulled towards the cam pully especially when the belt tension's too tight, which would have caused this to begin with.
Also check that the mount bolt at the distributer end of the pump (opposite end from the pully) is there and tight, if not, it could cause the front mount plate to flex giving the same belt prob's.

[fatmobile]

I recently pulled my in injection pump to convert to non-AC and found this:

 Good way to find this out and the new bolts got some blue locktite on them.
 The belt still wasn't riding off the pully.
 I have had them ride off the pully before and not leak or suck air.

 I went to look at an '85 Golf diesel. When I went to start it there was a bad belt rubbing on the timing belt cover kind of noise. Took a look and sure enough ... I quick shut it off and told him about it.
 I told my friend about it and when he went to check on it, the price had gone up conciderably.
 I learned the main cause for this problem and went back to let him know why it was running off. He had taken it to the dealership to get the belt changed.
 I told him they didn't fix the problem and if he checked, it would probably be running off the gear again. Next time someone checked on it, the price had gone back down.
 It's on my short list of cars to buy, fix and sell ... or have one of my friends buy it and pay me to fix it.
 So many VW diesels so little time.

[tylernt]

http://www.vwdiesel.net/phpBB/viewtopic.php?t=8057