I’m having a issue on start-up from cold there is a noticeable lumpy idling.

This hasn’t caused any massifier codes when scanning via VCDS.

Last year as part of the service the sparkplugs were changes but the rough idol is getting more noticeable.

My Audi had the same issue that eventually resulted in constant misfire. That was diagnosed as having a carbon build-up.

I don’t want to have the same issue occurring with the Fabia. As the CTHE is direct injection and has done 41k miles I’m guessing the rough idol is most probably needs a carbon clean as well but haven’t seen any posts on the forum about having it done on a MK2 Fabia vRS.

I did ask the Škoda dealer for a quote and they said it would be around £800 with a head gasket change.

I could go for an hour diagnostic at £160. As there were no error codes, I’m a bit sceptical about paying that and they say there is no issue found.

Has anyone else been through diagnosing cold rough idol as I don’t want to go to the expense of a carbon clean if it could be something else.

 

As I’m sure you know these engines are not very good and prone to many faults, many of which can cause a rough idle. It might be carbon build up or could be PCV issues, leaky injectors, vacuum leak etc..

5 minutes ago, whippersnapper said:

As I’m sure you know these engines are not very good and prone to many faults, many of which can cause a rough idle. It might be carbon build up or could be PCV issues, leaky injectors, vacuum leak etc..

That’s what I was worried about. Don’t fancy throwing the parts cannon at it.

From previous experiences going to a main dealer might not result diagnosing the issue after paying a premium.

I might try and find an independent garage that has some knowledge of working on the twin-charger engines and is happy to do some diagnostic work without charging a fortune.

We still have a Polo GTI with this engine. It has had a lot of work over the years.

8 hours ago, whippersnapper said:

We still have a Polo GTI with this engine. It has had a lot of work over the years.

This car hasn't needed any additional maintenance just yearly servicing with the dealer.

At 12 years old now I need to except some big bills as plastics and rubber start to break.

I was thinking if I should tuning it but with the engine'ss fragile reputation I've avoided doing it so far.

With a CTHE maybe time to get the Cam Chain measured. What Spark plugs were installed? Are you running E5 97 or 99 Ron Min Super Unleaded? What was the Air Filter checked?

Also you can try for a smoke leak test, if is a pcv o anything related to the intake sistem you will see the smoke escaping, however if you have vcds like said before look for chain stretch, fuel pressure and the activation and pressure for each injector

43 minutes ago, Evolution13 said:

With a CTHE maybe time to get the Cam Chain measured. What Spark plugs were installed? Are you running E5 97 or 99 Ron Min Super Unleaded? What was the Air Filter checked?

I'll do a check on VCDS for the timing chain stretch opefully being a low miage car this should be an issue.

New spark plugs were put in last September as I noticed a slight roughness on startup as the plugs have never been changed.

It has been run on 95 ron (not my choosing) but now I'm using the car it's getting VPower. Switching to VPower hasn't made any noticeable difference.

Not sure about the air filter. I would have thought it would have been changed as part of a major dealer service.

55 minutes ago, Jack25 said:

Also you can try for a smoke leak test, if is a pcv o anything related to the intake sistem you will see the smoke escaping, however if you have vcds like said before look for chain stretch, fuel pressure and the activation and pressure for each injector

That is useful list of things to check. Will need to do a bit or reading to make sense of the values from VCDS.

I'll mention it to a garage to do a smoke test if the VCDS numbers look ok.

A Major Dealer Service with Skoda has a Air Filter as being at 6 years / 60,000 miles now, and no guarantee that they bother their lazy arses to check at each service. So simples, best look in the Air Box. Plugging in and reading codes is one thing. Basics are basic. Look see. Lots of cars having Emissions / Control lights coming on recently. My cousins 1.8 TSI Beetle yesterday. IRAN war, and no idea what crap E10 is being delivered currently. (She normally runs on Tesco Momentum 99.)

Edited 6 July6 Jul by Evolution13

Re the Timing chain. There were issues with CTHE with mow miles as much as 8 years ago and there is a TPI. so just because low miles now means nothing................ This was my post in 2017 so 9 years ago & done because i was getting PM,s from members not wanting to post themselves & asking advice. So i looked for responses from other members. I knew the issue was serious for some.

Edited 6 July6 Jul by Evolution13

Sons mk1 idle was all over the place until warmed up. His brake servo hose was split. I taped it up and idle returned to normal. On yours were the coil packs changed at same time as spark plugs? They can sometimes cause rough idle until warmed up.

Alasdair

I got some VCDS data for the cam belt and injectors.

I think the cam reading is ok and the blet hasn't stretched.

Not sure if this is relevant for injectors but this is from a warm start.

There were slight fluctuation on the reading where each injector value one would dip under 1.0.