90 bhp tdi horror - Help - More with pics

[jezza16v]

Hi all. Just replaced the aux belt and tensioner pulley on '96 90 bhp tdi, no prob. Started the car up and let in run to charge up the battery. It ran nicely for about 2-3mins and then there was a horrible rattley tapping noise. We immediately stopped the engine to make sure all we had done was fine, was all still there and good. went to restart the engine and .......zip! It turns over well and we can smell diesel but it will not start, when the starter is turned off there is a buzzy clicking noise from near the fuel filter, but maybe that's normal? Help what has happened............Arrggghhhhhhhhhhhhhh! 

[FlySpeck]

I wonder if the timing belt tensioner went? Maybe it jumped a couple of teeth - it drives the injection pump on that engine does it not?

Hope its not serious as that tho mate, its a downer when they pack up mysteriously.

maybe the lift pump disintegrated, now wont prime the injection pump? Where was the rattling coming from, and was it light or deep?

[jezza16v]

Thanks, that was quick! It was definately a light rattle from the engine bay, but the bonnet was down so can't be more location specific. We took the cambelt cover off straight after to make sure it wasn't snapped, it wasn't but the cambelt and pulleys were completely smegged with oil, its not an old belt because the cylinder head was replaced a couple of years (20k) back (according to documents) so it was replaced then but the camcover gasket has been leaking oil for ages at the pulley end, we only fixed that a couple of weeks back but we guess the gasket was 'pinched' when the head was done (we've only had the car for 4 weeks btw). There is no tapping or rattling when we turn the engine over on the starter, it sounds normal, and it can be turned over fine on the crankshaft pulley bolt.
We thought cambelt 'slip' but is there an easy way to tell. The engine did not stop of its own accord, we had to turn it off with the ignition......Is that any more helpful?   

[FlySpeck]

its possible it jumped one or two teeth at most if it was still running, any more and it would have definately stalled, the only way to tell is either line up the cam pulleys and the crank pulleys with the marks on the engine casing, or do a compression test in one of the injector holes, but lining it up is easier without the proper gauge to read comp. If the belt jumps, the valve timing goes out slightly and that would make it hard to start.

Also if you unscrew one injector and crank it, there should be a nice burst of diesel every rotation, proving the injection pump is getting driven, tho if the belts not broke then it should be, but will show if fuel is getting to it from the tank too. Maybe the injection pump has failed inside, its very possible and may just be bad timing (no pun intended lol) and not related to the aux belt repair. Nothing else was slackened on the engine when the aux belt tensioner was done?

[jezza16v]

No, nothing else was touched on the engine while doing the aux belt. Just in case we haven't yet jumped the belt enough for the pistons to to clout the valves, we don't want to risk turning it over on the starter any more until we've checked the pulley alignments. But we wonder what the 'tapping' was, would that be the valves hitting the pistons or what? I've never heard that happen before but I would have guessed it would be a much louder scary sort of noise than the tappety tappety noise we had. Thought the engine would have stopped if the pistons hit the valves, it was just left ticking over to charge the battery. We watched the engine turning over on the starter with the cambelt cover off, all the pulleys are turning fine but the belt does seem a bit 'sloppy'. I guess I could have a go at putting some more tension into the belt with the tensioner just to make sure it does not slip any more while were fiddling with it.
Could it be anything else dumb and simple we could be missing? 

[Matty-MK3]

I doubt it, but the injector pump isn't by any chance run off the Aux belt is it? Or anything to do with it?

[FlySpeck]

no its off the timing belt.

I just wondered if the tb tensioner had been slackened by mistake, etc.

The aux belt is likely nothing to do wi the problem, id look elsewhere mate. If the tb jumped 2 teeth max, theres no piston contact. The valve timing would be out, maybe causing a kind of diesel death-rattle with the late timing causing a cooler charge so the diesel wouldnt burn completely?

Did it smoke out the tailpipe when the rattle started? Diesel smoke I mean.

[Matty-MK3]

Yeah that's what I'm thinking.

I have seen cars where they run of a double layered pulley off the aux belt, wasn't sure if these were similar.

It sounds to me like diesel slap, timing out. Most of the time when injector pump is out they are hard to start, rattle, pour out smoke and don't idle.

[Wayne]

Yeah that's what I'm thinking.

I have seen cars where they run of a double layered pulley off the aux belt, wasn't sure if these were similar.

It sounds to me like diesel slap, timing out. Most of the time when injector pump is out they are hard to start, rattle, pour out smoke and don't idle.

+1 check the timing.

[jezza16v]

We think it did start smoking, was dark, so hard to be sure, we thought at first it was a 'puff' from under the bonnet but think wind may have blown it under the car and out from the front (the wind was blowing that way at the time), we stopped it pretty quickly so not much smoke really. As said we were getting that unburnt diesel smell when cranking it over when it wouldn't start. Looking at the oily state of the cambelt and all the pulleys we're going for the belt slipping diagnosis, but which pulley do they normally slip on? I guess there's not much load on the injector pump pulley so unlikely to slip on that, most likely on the small crankshaft pulley which is doing the work or maybe the camshaft, that has a lot of resistance due to the valves.
Thanks for your comments so far, any other wisdom is more than welcome.
We'll have a closer look at the weekend and keep you posted on what we find.