Performance change after cam belt replacement?

[Julian Edgar]

Hi, my 1.9 TDI Roomster was going very well - bigger intercooler, straight-through rear muffler, custom intake, custom ECU reflash on dyno. (It's the PD engine.)

Then I got the cambelt changed at 105,000km.

The performance now seems stronger at the top end but much more sluggish at low/mid revs. The performance at 1500 - 2500 rpm now is back to being like a standard car - on the dyno mine was previously about 20 per cent stronger than standard at these revs.

After the new cambelt the idle is also now a little rougher and fuel economy seems a little worse.

Any ideas?

[Transporter]

Re-check the camshaft and crankshaft timing make sure that it was not moved by a tooth and the timing belt is correctly tensioned. If it was done properly performance shouldn't change.

[brad]

one tooth out?

[Julian Edgar]

I didn't do the cam belt change. The company that did it suggests that 'one tooth out' would result in a radical change in performance. Is this true on these engines?

[Jarred]

Aren't PD engines interference engines?

I know what the other guys are saying, but can't imagine that it'd be running very well (if at all) if it was one tooth out.

I don't have any evidence to back that up though, and I'm not about to go change my cambelt to find out.

Did you do it yourself, or at a workshop. Either way, checking the timing would probably be a good idea, as I think scanning the car would be. Might have a sensor that's unplugged, or something that's un related to the cambelt change has gone rye. Just spit balling though.

[Transporter]

one tooth out?

Never heard of?

[ST33VI]

If it is only a very slight change perhaps the old belt was a bit stretched, and now that it has a new belt the tune u had may b a tad bit off. If it is a substantial change it may very well b a tooth out, although usually low end suffers more then high end.
First thing to do is check cam & crank timing are correct and if they are maybe u need to retune.

[Preen59]

I'd suggest that maybe the cam timing is a tooth retarded.

Engines will run 1-2 teeth out usually, as long as there is enough piston to valve clearance.

[brad]

I didn't do the cam belt change. The company that did it suggests that 'one tooth out' would result in a radical change in performance. Is this true on these engines?

I've deliberately done "one tooth out" on other engines in a tightwads attempt to make it go faster (it moved the powerband and didn't really work). I've also managed about 3 or 4 teeth out (because I'm a crap engine mechanic) & the car would still run.

If they refuse to double check the timing marks then you should be able to check it yourself fairly easily.

[brad]

Never heard of?

As in the timing marks aren't lined up / mistimed. Not actually missing a tooth or anything like that.