51 minutes ago, MB21 said:

I was hoping that I could come back with some positive news, but the garage are still working on it. They've refitted the cambelt having carefully gone through everything, and put it back together, but still getting the same result. They maintain they do 2 or 3 of these every week, and not previously encountered the problem. They recognise there is a problem, and accept that it is likely to have been caused by the cambelt replacement. I'm hoping to hear again in the morning, and will keep you posted.

 

I saw @Twiz had a similar issue, and concluded it was the harmonic balancer had been refitted incorrectly. I've highlighted this to the garage, but they weren't convinced. I assume this isn't replaced as part of the cambelt kit?

 

Also saw that @toot and @ForCar40 posted a link from mechanic expert on the Mk7 Golf timing belt replacement - the link is no longer live. I don't suppose anyone else has a copy / live link that I can access?

 

Thanks all for your help.

 

Really sorry to hear that they are no further forward @MB21 

 

I'm trying to find the similarities/differences between the work done on my car and the work done on yours so we can try and narrow it down - do you know if your garage used genuine Skoda parts for the cam belt and what the part numbers are? If we are both genuine Skoda parts/same part numbers then it's maybe a duff batch of parts that we have both been hit with? I'm presuming that they are also following the Skoda issued guide/instructions for the work? Wonder if there's an error in the instructions? (Seems a bit unlikely but you never know...)

@MB21For reference, this is the parts list that was included in my paperwork from the garage - be interesting to see if our parts list matches

I have got the car back from the garage now.

 

They believe it was a faulty coil pack on one of the spark plugs. They've replaced the offending coil pack and all the spark plugs - they were only replaced last year, but made sense to do them all at the same time. The one spark plug was discoloured on the body in comparison to the other two. The error wasn't showing up on the diagnostics, but it could have been within the software tolerances  🤔

 

The vibration is significantly improved, but it is still just about noticeable at around 1200 revs. However, I have little to compare it against. We've agreed that I will drive the car for a while and see how it goes. They are confident that the timing is spot on.

 

@DaniP They don't routinely source their parts from VAG, but ensure they only use reputable manufacturers. I had wondered whether it could be a manufacturing fault, but I suspect it's unlikely given the number of these being manufactured by different companies for VAG.

 

It would be useful to know from anyone running a 1.0Tsi with the original cambelt whether there is any noticeable vibration from the engine around 1100 - 1200 revs.

 

I'll keep you posted on how I get on. But thanks everyone for your contributions.

 

Thanks so much for the update @MB21! Really glad to hear that things are if not 100% fixed than significantly improved. Is there any theory/explanation around how/why the coil pack issue could have happened or become obvious post cam belt change? Is it just a bizarre coincidence?

 

I'll be sure to share all this info with my garage when it goes in next week and I'll update with how it gets on and what they find 

@DaniPI can't see a link between a cambelt change and a coil pack failure. The coil pack had evidently been failing for a while, given the colouration on the spark plug, so why we weren't experiencing vibration before the service - I don't know. Perhaps the previous cambelt / tensioner / roller was better at absorbing the vibration? I honestly don't know.

 

I suppose there is an outside chance that the coil was knocked during the cambelt service, which resulted in the failure. The good news is that it is very easy to check, and should take your garage only 30 minutes to whip the air filter housing off, and check each of the spark plugs. I wouldn't rely on a diagnostic tool, as it didn't show up on my car. 

 

My garage, I feel, have been very fair - why I like a good independent. Despite spending hours refitting the cambelt (twice) to check they hadn't made any mistakes, they only charged me for the new coil and a set of spark plugs and have absorbed the labour. 

 

Will be interested to hear how you get on next week - fingers crossed!

@MB21 I can say with a fair degree of certainty that my garage probably won't be as reasonable with the pricing! So long as it gets fixed though that's the most important thing - I'll definitely keep you updated

No fix for mine yet but here's what I've been told by my garage so far:

 

- Diagnostics have come back with no faults or errors

- Timing has been checked and it is all perfect

- Initially I was told that one of my spark plug pins was slightly bent but in a follow up update I was then told that it wasn't in the correct position(?) and that was then resolved which made no difference

- They then swapped out the coil pack and spark plugs with a different car and that made no difference either

 

They do acknowledge that the judder/roughness is there

 

So it's still with them, and I will hopefully get a further update tomorrow or Friday when they've had time to look at it some more

 

@MB21 how has your car been feeling after getting your work done?

 

 

@DaniP Sorry for the delay in replying - been away for a few days.

 

My Fabia appears to be behaving itself since the change in coil pack and spark plugs. There is still a noticeable, but very faint, vibration - but this could have been there before the cambelt change, and I am probably only sensing it because I am looking for it. Before, the whole car was shaking at c. 1,200 revs with the car stationary and in neutral.

 

Just to be clear, it was only 1 of the 3 coil packs (that sit on each of the spark plugs) that was found to be at fault on my car. Did your garage check / swap out all 3 on your car?

 

Hope your garage get it sorted soon - will be interested to hear how it pans out. 

@MB21 From what I've been told by the garage, they've tried new coil packs and spark plugs so I can only assume they swapped out all of them - they said it made no difference 

 

I'm expecting an update either today or tomorrow so I will let you know what they find. I need to press them for a bit more information because I'm not clear if they're definitely seeing misfires (which would send them down one route of investigation) or if it's something vibrating in/around the engine which would send them down a different route, like checking engine mounts and the like

 

Hoping for positive news soon, I've been without a car for nearly a week now which I am not loving!

Car has been returned 😁

 

Root caused was tracked back to the crankshaft pulley (which I've also seen referred to as the harmonic balancer) being in the wrong position which was causing juddering and vibration. Exact same issue that Twiz had with their car in this post: https://www.briskoda.net/forums/topic/506382-12-tsi-running-rough-after-cambelt-change

 

 

I've driven it a bit and sat it in neutral and ran through the revs and I can't pick up on any juddering or roughness now so I am satisfied that it is fixed

 

@MB21 in relation to the really slight vibration that you can detect at 1200rpm still - I can detect something at that rev point too but like you it's exceptionally subtle and I don't think I would have noticed it were it not for the fact that after having this issue I'm hyper sensitive to anything relating to vibration or changes in engine noise. It's something that I am happy to put down to "that's just what the engine sounds like" and leave it at that though

 

Fingers crossed for smooth driving for some time now!

@DaniP Pleased you've got it resolved.

 

Now left me wondering whether the coil pack fix was incidental to the problem I experienced. I had suggested to them about checking the harmonic balancer, but they were adamant that it was fitted correctly. I wonder if in the process of refitting the cambelt they unknowingly corrected the positioning of the harmonic balancer / crankshaft pulley and also swapped the coil pack at the same time while the air intake was off.

 

Car seems fine now, and I am convinced I am being overly sensitive about the remaining vibration.

 

 

I would not take anything that a garage trots out as gospel, quite the opposite in fact.

 

Crankshaft pulleys are usually fitted with a keyway and can only be fitted in one position, without it or if there is even the slighttest movement in the drive key it will shake loose and wreck the crankshaft, this is doubly true on the much heavier harmonic balancers with a much greater moment of inertia.

 

Can anyone confirm whether the crankshaft pulley on this engine is free to be fitted in any angular position?

 

A harmonic balancer certainly does not need to be fitted in a certain angular position, they are not weighted at a certain position and would function in any orientation but would need immense clamping pressure if no drive key.

Edited 3 June, 20233 yr by J.R.

There is a very good reason that there are warning about needing the right gear and more than just ideas and how easy it is to mess doing the cam belt replacement on a 1.0 tsi. (Even easier with the 1.4 or 1.5 TSI engines with ACT to mess up.)

 

Easy for those that mess up not to admit it and blame something that was not faulty pre them putting on their work gloves.