Jerky vibration from engine?

[JoeDarKa]

Hi all,

Got an issue with the car. Its a 2.0 tdi, 73k miles.

When travelling at 50mph+, im getting a gradual onset of a jerky / vibrating sensation thats quite severe. Iv been in 6th at 70mph when its happened both times. When i slow down to below 50mph it seems ok.  It happened a few weeks ago, thought it was the tyres which are worn and grumbling which i got checked out and rebalanced so dont think its them. It hasnt happened since until today.  Iv scanned it on ignition and had no errors. Im going to rescan it with the engine running.

Any ideas? EGR clogged? Injectors? Glow plugs?

Iv not really tested much as iv been more concerned about getting off the motorway!

Im currently at work which is 25 miles from home, 99% motorway so debating what to do!!

Cheers

[Shoduchi]

A bad EGR can compromise engine performance. I'd only consider injectors if a log would suggest that, or the rest was excluded. Glow plugs are really only needed when cold starting bellow 8ºC or something like it.

Try rotating the tyres or test different ones too.

[xjay1337]

Need a bit more information...???

Is the jerky / vibrating sensation there on steady throttle, accelerating, coasting? does it go away if you change gear / loads
i have an issue during my warm up if i'm at around 1300rpm on part throttle i get a jerk through the car. i can see on my polar that my fuelling is jumping from 16-18mg/str to 35mg/str. This only occurs between certain engine coolant temps between 50 and 60 so not too much of an issue and easily drive-aroundable by dropping a gear.

Any logged faults would show irrespective of engine running or not.


EGR can cause rough running and poor performance and so can injectors failing. On whatever diagnostic tool you are using look at injection quantities and also per injector compensation this will be a figure of + / - mg/str on d1~4. this is injector 1-4 and how much less (or more) it's actually injecting than specified. mine rarely goes above 0.8 either way, and usually they are all within 0.2 of each other.

if one is injecting far less or far more then you have an issue.

but afraid we can't do anything with the info you have given us so far :(

[JoeDarKa]

It happens on steady throttle at 70mph and whilst coasting down from 70mph to 50mph. Its been fully warmed, steady 90 degrees both times its happenend and both occured towards the end of each 25 mile journey.

Iv not had chance to test it any further as iv been more concerned in getting off the motorway. When i have come off however, its ran fine but maybe a bit lower on power.

Il scan it tonight using VCDS

[JoeDarKa]

[xjay1337]

Those are all normal. if it happens when driving recreate the problem and check the values
check Egr as well.

[JoeDarKa]

Those are all normal. if it happens when driving recreate the problem and check the values
check Egr as well.

Thanks, thought as much. Doesnt help im going on holiday soon so will be parked up. I do have a egr delete kit from darkside which iv had for yonks which i might get round to fitting now!

[howie1987]

Sounds similar to when i snapped my dogbone mount bolt. engine moved forward a little and it was jerky and laggy.

Probably not this but worth a look.

[JoeDarKa]

I made it the 25 miles home without a problem but i left it in 5th and stayed around 60. Il try the dogmone mount though!

[xjay1337]

Easy to check, rock the engine from the top. excessive movement will be pretty easy to spot.