Last week the VRS got its first new timing belt as well as MOT (its just shy of 50k miles I think).

Now, at idle it seems really juddery (at traffic lights etc.) Has anyone else had this or is this the result of poor work?

Thanks in advance,

Paul

can only suggest if its only since new belt it may be a tooth out..

can only suggest if its only since new belt it may be a tooth out..

its not huge, but its both myself and the MRS have noticed it independantly, back to the dealer?

Indeed! sounds like it might be a tooth out! :(

Mike

Indeed! sounds like it might be a tooth out! :(

Mike

This dealer experience doesn't seem to be improving!

Normal until belt has time to settle in and stretch slightly. Easy check, switch on aircon or heated rear window, if it settles down with extra load all is well. If it was a tooth out car would run like a pig.

Normal until belt has time to settle in and stretch slightly. Easy check, switch on aircon or heated rear window, if it settles down with extra load all is well. If it was a tooth out car would run like a pig.

Will do that later... its certainly not a pig, it just vibrates my backside whilst at lights.

good job moggy is about...

was gona say that as there are marks to line the crank/cam up its a mistake a dealer shudnt make...

Provided the proper locking tools are used it's almost impossible to get the belt fitment wrong. Where some garages get confused, is regarding the final position of the camshaft sprocket after the belt is fitted, not helped by the fact the Skoda manual is a bit confusing into the bargain.

Hmmm its really odd.

Just took it out for a quick run. At idle when stationary its fine for about 30 secs then starts to 'chug' a bit before getting worse until the point you can hear something. Turn on a/c, heated seats and heated screen and this dies down almost instantly, and comes back if you turn it off.

Its on the low side for oil so I'll give it a bit more in the morning... (anyone know why I wouldn't be getting notification replies? I'm subscribed to this thread and they're not in my junk?)

edit: delayed notification was on

seems like one of the injectors wasn't quite right. They plugged it in and altered the amount of fuel it was putting in at idle and it seemed to sort it out.

Good service, bad of me to doubt them (I won't do it again).

Strange one indeed, glad it's fixed though...

mine is doing exactly the same i sent it back to dealers because i thought it was dual mass failing again. they rung me and told me they had increased the idle speed slighly to 880rpm and that the problem was fixed so i picked it up and 30mins later it was back juddering again.

mine is doing exactly the same i sent it back to dealers because i thought it was dual mass failing again. they rung me and told me they had increased the idle speed slighly to 880rpm and that the problem was fixed so i picked it up and 30mins later it was back juddering again.

that knocked it down to 720 Rpm on mine (its a lot quieter at the lights). It still judders, but its not uneven as before. When I increased the load on the engine (you'd think it'd have something against a/c on full cooling and heated seats on buttock roasting!) it reduced significantly so I'm wondering if the new belt just made it all the more evident?

I hope I get this right, as it's been a while since I studied the PD bible. The VRS tended to judder slightly at idle when new, and it stopped juddering if you turned on the aircon or heated rear window. The engine is designed to use minimum fuel at idle, and when the timing belt is new, you get a bit more drag between the belt and various pulleys. Turning on aircon or heated window requires the ECU to give the engine more fuel to maintain the correct idle speed.

The timing belt system is complex, as the cam sprocket has a built in damper to reduce belt wear, due to the loads needed to pump the mechanical part of the injectors (29,000 PSI). The cam sprocket also has some teeth spaced slightly wider apart, to stop whiplash effect in the belt.

As the belt settles in, it stretches VERY slightly, relieving some drag, and you get a smoother idle. I had the cambelt done a few weeks back, and only get a slightly lumpy idle, just as the engine reaches optimal temperature, it's fine when cold, and again when properly warmed up, so it's not there all the time.

So basically, the fuel values are slightly too low with a fresh timing belt for smooth idle.

Good knowledge!

(Does this mean it'll be too lean when the belt settles in?)

I hope I get this right, as it's been a while since I studied the PD bible. The VRS tended to judder slightly at idle when new, and it stopped juddering if you turned on the aircon or heated rear window. The engine is designed to use minimum fuel at idle, and when the timing belt is new, you get a bit more drag between the belt and various pulleys. Turning on aircon or heated window requires the ECU to give the engine more fuel to maintain the correct idle speed.

The timing belt system is complex, as the cam sprocket has a built in damper to reduce belt wear, due to the loads needed to pump the mechanical part of the injectors (29,000 PSI). The cam sprocket also has some teeth spaced slightly wider apart, to stop whiplash effect in the belt.

As the belt settles in, it stretches VERY slightly, relieving some drag, and you get a smoother idle. I had the cambelt done a few weeks back, and only get a slightly lumpy idle, just as the engine reaches optimal temperature, it's fine when cold, and again when properly warmed up, so it's not there all the time.

So basically, the fuel values are slightly too low with a fresh timing belt for smooth idle.

I drove it again last night (its the MRS. daily driver) and its still pretty awful especially when stationary on uphill gradients.

Is there anything else I should start looking at? Its only come about since the belt change but it really is quite lumpy now at tickover, even with the injectors adjusted.

I drove it again last night (its the MRS. daily driver) and its still pretty awful especially when stationary on uphill gradients.

Is there anything else I should start looking at? Its only come about since the belt change but it really is quite lumpy now at tickover, even with the injectors adjusted.

If it's doing it after engine reaches proper operating temperature there is a problem somewhere. If there are no fault codes I would suspect either the belt is over tensioned, or they got the cam sprocket alignment wrong. Fitting the belt involves slackening the three bolts on the cam sprocket, and rotating the sprocket to it's end stops. Engine is then reset to TDC on number one cylinder, and the cam sprocket rotated so that the locking tool can be re-inserted into the head flange, and the three bolts are then tightened. This is then double checked by rotating engine 1/4 turn the wrong way, and back to TDC, and checking the locking tool once again fits into the flange.

It is that procedure that sets the basic injector timing, and some garages get it wrong from time to time.

If it's doing it after engine reaches proper operating temperature there is a problem somewhere. If there are no fault codes I would suspect either the belt is over tensioned, or they got the cam sprocket alignment wrong. Fitting the belt involves slackening the three bolts on the cam sprocket, and rotating the sprocket to it's end stops. Engine is then reset to TDC on number one cylinder, and the cam sprocket rotated so that the locking tool can be re-inserted into the head flange, and the three bolts are then tightened. This is then double checked by rotating engine 1/4 turn the wrong way, and back to TDC, and checking the locking tool once again fits into the flange.

It is that procedure that sets the basic injector timing, and some garages get it wrong from time to time.

this was a dealer and they assured me last time the timing was fine?

this was a dealer and they assured me last time the timing was fine?

In that case out ideas, sorry.