I've heard of this happening, but never actually saw it myself. Perhaps someone might be able to give some insight as to WHY this might have happened.
Ok, here's the story:
Customer's car. 1981 Rabbit with a 1986 Golf Engine with about 150k on it. The car has great compression, and runs well, but is an electrical nightmare, and the engine is coated with an inch of goo. He brought it to me to fix a leaking injection pump. Eventually, I pulled off all the AC brackets and mounting brackets to replace the water pump o-ring on the block, and the heater hoses (pump had been leaking badly).
Well, he was a cheap-o, and wanted to do the bare minimum. I suggested a timing belt and tensioner, but he recently (about 20-30k ago) had it replaced. So, i just re-used his belt and tensioner.
As for the pump, I got his pump off, and it had some problems. It looked like someone had dropped it on the floor a few times. There was a dent on the cold-start advance housing which had taken a small chunk out of the pump housing. I was afraid would it would leak if I replaced that seal. Also, the cold-start lever would not move at all. I found out later when I took the pump apart, that someone had hammered on the IP shaft to get the sprocket off. When doing this, they had bent the internals of the pump housing: nice.
So, to make a long story short, I ended up resealing one of my old pumps (known to work fine), and put it on his POS cruiser. The pump has a light film of rust on some of the internals, but had worked just fine. So, I went about resealing it. It was my 4th reseal, so I'd gotten pretty good at it. My only problem when I reseal is that I often pull the whole IRON distributor head off when I do the job, just to clean out all the rust that often builds up on the sealing surface. When I do this, I often use Vaseline to hold the internal parts in place (a tip I picked up from Andrew).
Anyway, I installed the pump on his car llast December, set the pump timing and set the belt tension with my VW210 tool that I use all the time. I've done about 3 dozen of these TB jobs, so I know what I'm doing.
So, the owner picks up his car, and drives off into the sunset. He got a REALLY good deal on the labor and part,s considering his pump was basically useless to me, save for the internals.
Well, he called me about 2 weeks into January, and said the car had no power. He had been driving it, and it was fine. Then one really cold day (about 10 degree F), he took it to the store. It was fine to the store. He parked it. Then, when he tried to start it, it was really doggy, and he barely made it home. White smoke was pouring out the back as he limped home. It should be noted in this, that he had just filled his tank with some old summer diesel he had in a jerry can in his garage. I think he had nothing but summer fuel in it since he drove it December-January.
Ok. So, I thought maybe his fuel had gelled, and that was the problem, or the filter was clogged. So, new filter, and I checked the in-tank screen. Evrything looks good. I installed a clear plastic fuel hose, and injector return lines. It still runs like pooop despite pumping fuel no-problem. So, I figured it must be the pump, and I would have to return to replace the pump (at his house). Well, a month passed before I could get back. In that time, I thought about what I might have done to the pump that would make it run like crap.
Anyway, I finally got back out to his house to check things out (nice and warm here in TN yesterday). The first thing I did was check the pump timing. Sure enough, the pump is out one full tooth. I'd never seen that in my life. I know it was timed right. I even checked the static pump timing with my dial indicator after I reset the belt: it was spot-on at 1.00 mm where I had set it. So, somehow, the ONLY the pump had jumped time. The camshaft and the crankshaft were still spot-on, and the compression was great.
Can anyone come up with an explanation at to WHY this might have happened. The only thing I can think of is, residual Vaseline, or gelled fuel had made it difficult for the motor to pump the fuel either in the vane pump, or thru the metal pipes. The motor kept on spinning, and the pump stood still.
Any thoughts?
I'm hoping not to have to revisit this turd-herder of a car. So, if anyone can come up with a reason why, in case I do have to revisit this thing.
P.S. I reset the belt timing on the car, tinkered with the idle and fuel screws, now it runs even better than it did before.
You said the motor was full of oil. Is it possible the back of the belt is oily and that's why it jumped? Also i have heard that the gear [pick one =-IP, cam ..] teeth can get so worn and round [instead of square] that the belt will slip. I don't think your vaseline is the problem, it would have happened sooner.
did he buy the tensioner from prothe???
did he buy the tensioner from prothe???
Nah, he bought it local. The gears on the IP looked good. The belt was a little slick but not really oil. It wasn't leaking oil on the belt: it just looked a little shiny. The tension was set right, and the tensioner was locked tight.
I'm still at a loss. If it comes back, then I think I'll tell him to replace the belt.
i had this happen on mine after i had done a cam belt change, just assumed i hadn't adjusted the tensioner enough, retimed it and its been fine since.
Was the timing cover properly fitted?
Andrew
As far as I know. Its the stock Rabbit metal cover, with all original bolts and spacers. Not sure how that would affect it?
i had this happen on mine after i had done a cam belt change, just assumed i hadn't adjusted the tensioner enough, retimed it and its been fine since.
Well, that's good to hear. Hopefully it was just something stoopid I did, and i won't recreate the events that led up to it.
JB
I've heard of it happening a couple times.
Often after a sudden change in RPMs,.. not sure a startup or shutoff qualifies but maybe.
I think the tensioner holds the belt tight to the cam sprocket,..
The belt bends tightly around the crank,..
it's the injection pump that has the fewest degrees of contact with the belt.