Juddering on idle

**magebora** · 20-02-2009,02:23 PM

I have a PD 130 bora, when cold she judders on idle, i had the flywheel and clutch changed but the juddering still persists, when shes warm she idles fine. Anyone any ideas what the problem might be?

Thanks.

**Crasher** · 20-02-2009,02:33 PM

Possibly an injector harness or even an injector fault but if it clears when warm it can be awkward to track down. Another common problem is wear of the injector arm lobes on the cam. You will need to get someone to read the ECU for fault codes and if non are stored, analyse the data in Measuring Blocks 08 Display group 018 and 013 to check the status of the injectors and possible also have the cam cover removed to check the lifter lobes.

**Deeps** · 20-02-2009,04:29 PM

If by "juddering" you mean a mis-fire, then that is exactly what I have with my Bora 130 TDI SE Tiptronic. It only happens when the engine is cold and only when the throttle is shut i.e. tickover. I also get a creaking noise from the the throttle pedal area - maybe this is associated with the mis-fire?
As soon as she warms up the mis-fire goes away. The car runs perfectly apart from that. Starts first time every time; gives me around 50mpg on a run...not bad for an automatic.

I'm booked in to the the VW main dealers for a service and MoT in 2 weeks time, so I'll get them to diagnose it........and wait for the big bill ! I'll let you know how it turns out.

Regards,
Mike

**Crasher** · 20-02-2009,04:59 PM

The creaking is the throttle pedal unit but not associated with the misfire, if the pedal unit even goes slightly faulty (apart from them sticking open slightly), the EPC light will come on.

**Deeps** · 21-02-2009,07:03 PM

Thanks for the advice Crasher.
What causes the throttle to creak?
Should I be worried about it....how can I fix it?

mike

**Crasher** · 21-02-2009,08:18 PM

The pedal unit ages internally, it is an all in one unit, the only cure is a new unit-part number 1J2 721 503 H for a diesel manual but I can’t tell you the price from home but I think they are around £60.

**Deeps** · 10-03-2009,08:42 PM

I took my Bora to the VW Main dealer for an oil change/service/MoT and asked them to investigate the misfire. Iexplained it was only evident from a stone cold start - not initially but after a few minutes before the engine has warmed up. The misfire goes away when the temp is about 70; it usually sits spot on 90.
So they changed the AMM and told me it was fixed. It wasn't.
They kept it overnight so they could do a cold start. They cleaned the EGR and told me it was fixed. It wasn't.
So I'm going to have to go back again. Sounds like your injector harness idea might be the way to go. Can they not diagnose that via VAG-COM?
Regards,
Mike

**Crasher** · 10-03-2009,10:30 PM

The harness will usually show up as a fault so they will have to use the live data screens and their brains-dohh!

**Deeps** · 13-03-2009,08:16 PM

Hi Crasher, this is turning into a farce.

First they were certain the misfire is caused by a faulty AMM. They replaced it and it made no difference.

Then they decided it was a dirty EGR valve. They cleaned it and it made no difference.

Then they said they needed to replace the EGR valva AND remove/clean the inlet manifold (at a cost of £300). They cleaned the inlet manifold and it made no difference (the new EGR valve has not arrived yet).

The Service Teram Leader called me tonight and said sorry they had not fixed it (they've had my car a total of 6 days) but he had contacted VW in Germany and their response was they had seen this a number of times and the ECU should be replaced ...at a cost of £900 !

I told them that someone had suggested a faulty injector harness might be the culprit - but he said no fault code was stored for that.

I am going to collect my car in the morning. If you are happy for me to do so, I will pass on the info you gave me about analysing the data in Measuring Blocks 08 Display Group 018 and 013 to check status of the injectors.

I guess I will end up paying the £300; but I'm damned if I'm going to fork out £900 for what sounds like a 'best guess' on their part. I'd appreciate your thoughts.

If it comes down to it I'll take a couple of days off work and drive up to Nottingham to have you take a look; I don't have much confidence in this lot.

Mike

**Crasher** · 13-03-2009,10:08 PM

The problem is I am going to need the car overnight for at least a couple of days and that is going to cause you terrible inconvenience if you come up to me. PD ECU failure is extremely rare and the only case I have seen of this on the PD leaves 5 specific fault codes that you are not reporting. The live data info is not much use on a cold engine as the results are only relevant over 80°c. Can we go back to the beginning and think about how the problem manifests itself? During hot running, the car is perfect in all aspects? When the misfire is there during cold running, is there an irregular knocking from the engine bay on the left hand side of the car?