Hi,

I had a cambelt change done on my remapped PD100 (Polo, not Fabia) and ever since there has been an issue with the MPG and power delivery. MPG had dropped 10-20% and power delivery is all at the top end (3k rpm+).

I took it back to the garage to recheck the alignment as I wasn't happy and we had the arch liner and cambelt cover off and I confirmed that it looked OK according to the Bentley diagram.

To do the belt the guy didn't have the VW tool but lined it up using marks on the pulleys/block made with tippex before the original belt came off (?!) I guess the theory is right.

My question is - is there anything else that should be done, or is this a coincidence.

I also checked for faults but only using the generic tool he had. My next step is to get a VAG-COM owner to plug it in for exchange of a few beers!

Any help is appreciated.

Seems a bit odd that - hopefully one of the knowledgeable ones will be around to answer your question

the correct locking tools should always be used when doing the timing belt on the PD engine , otherwise problems can occur , the worse case is that the valves hit the pistons , i would get it re-checked by someone with the correct toolage

So as long as the timing is set up in the right way, there's nothing else in a cambelt change that could cause these issues? - I was worried about sensors, hidden things that might need doing and so on.

the thing is though , to correctly adjust the belt tension , the bolts on the cam pulley need loosening, with the cam locked , so without using the pin to lock the cam , i don't see how the belt can be correctly set up , this could also mean the cam is incorrectly timed up

I would say the fuel pump timing has been lost. Get it to a garage that has the correct tools.

I would say the fuel pump timing has been lost. Get it to a garage that has the correct tools.

Agreed, even though there is no actual fuel pump to time up on the cambelt the camshaft timing needs to be right so it runs the injectors at the correct time. The ECU can adjust but only so much. Not to mention that if your cambelt timing is out the valves etc wont be opening and closing at the right time.

:+1: - even if the valve timing is correct, the fuel timing sounds out!

Thanks,

Is this something VAG-COM could pick up?

:+1: - even if the valve timing is correct, the fuel timing sounds out!

Not something you can seperate unless the rockers are out of adjustment.

Easy enough to recheck the timing with the correct tools.

i seem to remember that there is no timing mark on the crank pulley on those?? ross?? it's on the outer cover iirc?

Yeah there is one on the outer cover and the pulley, this would do for double checking (as would the flywheel mark) as you could set the crank then put the pin in the cam.

I just got an email to remind me to log in about this - I thought I would add the solution rather than keep this as yet another unanswered problem.

The cam belt tension was out, causing all sorts of bad timing depending on the revs. I took it to Storm Developments and they diagnosed the problem (statically it all looked fine) retensioned it and all was sorted.