Cold start juddering - no fault code?VW Tiguan 2012 2.0 tdi

[passport010]

Hi there

Wondering if anyone can help.

I have a 2012 Tiguan 2.0 tdi 4 motion manual. It has started juddering under power when cold.

It idles fine, and when it’s warmed up (5-10 mins driving) it stops doing it. It is much worse when the weather is colder. Its down on power while juddering and the sensation is somewhere between being in too high a gear and going over a rumble strip.

It has not thrown any error codes. I had assumed it was a bad injector but the garage I use says an injector would throw an error. So we’re unsure where to start!

I have tried driving with premium fuel and I have added injector cleaner to the fuel but neither seem to have helped.

Any ideas on things I can try at home before throwing loads more money at it? I am competent at basics.

Other things: car has 83k miles, full service history, had a new clutch and flywheel and cambelt 2 years ago, it’s in generally good order otherwise.

Thank you

Edited by passport010 on Monday 6th February 13:06

[E-bmw]

Sounds like a glow plug being down to me.

[Demelitia]

Surely a glow plug wouldn’t be the cause of the issue if it persists for 5-10 minutes of driving? They’re usually only the cause of lumpy running for under the first 30 seconds.

[stevieturbo]

E-bmw said:

Sounds like a glow plug being down to me.

modern car would usually report that anyway

Pretty sure VW's have decent misfire counters....get a proper scan tool and view data

[passport010]

Thanks for replies.

Fairly confident that it’s not a glow plug, as has been said that wouldn’t affect running in this way, and it would throw a code.

I can try the misfire counter (not familiar with this) but what would that reveal if there’s no error code?

[stevieturbo]

most modern cars will tend to indicate if a cylinder is misfiring. And it will point you to which cylinder

Obviously determining whether one cylinder is affected, more than one, or all....is important information.

[E-bmw]

stevieturbo said:

E-bmw said:

Sounds like a glow plug being down to me.

modern car would usually report that anyway

Pretty sure VW's have decent misfire counters....get a proper scan tool and view data

I wouldn't disagree, but then above the OP says there are no codes anyway but you would expect a report of something going by what he says.

[stevieturbo]

E-bmw said:

I wouldn't disagree, but then above the OP says there are no codes anyway but you would expect a report of something going by what he says.

Many people come on here and claim no codes. Often falsely....just that they are using incorrect tools that cannot communicate properly to see the fault codes.

And I did also say to view relevant live data to see if anything looks amiss during the poor running

It could still be an injector problem, it could be a fuel supply, air, other problem with no codes. But to be sure there are no codes, they also need to be sure their equipment is capable of reading all the data.

[passport010]

Well the garage says no codes, and there is no Eml or other light in the instrument cluster

[Belle427]

May be worth inspecting the fuel system, especially the injectors if the engine uses the single stretch bolt and clamp arrangement to hold them in.

[stevieturbo]

passport010 said:

Well the garage says no codes, and there is no Eml or other light in the instrument cluster

So have you just bought this car or something ?

No light means someone has likely removed the bulb or disabled it.

Seriously...find someone with VCDS or at least a proper scan tool and have them scan it. If there is no EML at all....that is another problem that needs addressed.
And hope some dodgy remap place hasn't remapped it to remove stuff, or any ability to report faults.

[passport010]

No, I’ve owned the car since 2015 and I bought it from Vw. No dodgy remaps. And I don’t think people “remove bulbs” from complex modern instrument clusters “” circuit boards anymore - is that still a thing?!

This thread on another forum is interesting. Obviously a much older Vw but Crasher suggests there are things that don’t leave fault codes.

https://www.vwaudiforum.co.uk/forum/showthread.php...

[passport010]

Or how about this one, fuel filter?

https://www.vwaudiforum.co.uk/forum/showthread.php...

I’ve never changed the fuel filter and put cheap stty Morrisons fuel in recently. Maybe it’s fuel starvation?

[Belle427]

Always start with the basics, if the fuel filter has not been changed for a while then do it but I'm doubtful it's that.

[E-bmw]

stevieturbo said:

E-bmw said:

I wouldn't disagree, but then above the OP says there are no codes anyway but you would expect a report of something going by what he says.

Many people come on here and claim no codes. Often falsely....just that they are using incorrect tools that cannot communicate properly to see the fault codes.

And I did also say to view relevant live data to see if anything looks amiss during the poor running

It could still be an injector problem, it could be a fuel supply, air, other problem with no codes. But to be sure there are no codes, they also need to be sure their equipment is capable of reading all the data.

You are correct, and of course it could still be many things, of which injectors would certainly feature high.at the top of the possibility list.

[E-bmw]

passport010 said:

Or how about this one, fuel filter?

https://www.vwaudiforum.co.uk/forum/showthread.php...

I’ve never changed the fuel filter and put cheap stty Morrisons fuel in recently. Maybe it’s fuel starvation?

Fuel filter wouldn't give the symptoms you describe but as above start with the basics.

Yes, people do still disable/remove/cover CEL with black tape etc just to seemingly demonstrate a working car.

I even came across one a few years ago with the CEL de-soldered from its correct circuit & re-soldered to the oil warning light, so it operated seemingly correctly.

[stevieturbo]

passport010 said:

No, I’ve owned the car since 2015 and I bought it from Vw. No dodgy remaps. And I don’t think people “remove bulbs” from complex modern instrument clusters “” circuit boards anymore - is that still a thing?!

This thread on another forum is interesting. Obviously a much older Vw but Crasher suggests there are things that don’t leave fault codes.

https://www.vwaudiforum.co.uk/forum/showthread.php...

many people will do the strangest of things, instead of just fixing correctly.

And of course many faults can occur where no fault codes are present.

But if you're saying there is no CEL ever....then clearly someone has done something. Chances of the light itself just being faulty, is rather slim.

[passport010]

Well I changed the fuel filter yesterday and……. It’s not fixed it! 🙁

Any ideas on what to try next? Mass air meter? Egr?

FYI the CEL does work .. you can see when you start the car

[Belle427]

I wouldn't just fire the parts cannon at it, that's a recepie for disaster.
You really need someone that's able to confidently look at live data and how to read it.
Finding someone is your problem, unless you fancy buying vcds and having a go yourself but this wouldn't be much help if your not sure of what your looking at.

[andybracing]

A code reader is just that, some things wont triger a code, something only just out of proper range may not show a code but could cause a problem, and alot of bits wouldnt trigger a code anyway, bad spray from an injecter, may not for instance.
Dont forget we used to be able to fix cars in the days before code readers etc, in the early days of efi any diagnosis had to be dont the old fashioned way, yes code readers have a use, but they are just a tool like a spanner is. but you need to know what its telling you, or even more what it isnt, live data is even better, but again you need to know what to look for. A code reader doesnt make a mechanic. I think you need to find someone who really knows what they are doing, very different to the avarage guy in a garage, most guys today mainly are fitters not mechaniics unfortunatly, they are great at service items, clutches etc,but modern cars are so complex, you do need a real knowlage, and idealy someone who knows the engine well. It could be a fault with alot of things, and chucking parts at it isnt the way forward, however changing the fuel filter isnt a bad thing