The notorious PD TDi engine judder

[stewpot1776]

Hello all,

as many of you have had this experience I thought I would throw it out to you on your knowledge. I have spent endless hours reading and trawling the never ending threads across a few forums on this topic.

I have not yet checked the EGR valve yet however VCDS said it was on 60 which the in between zone said something like 5-65.

The MAF initially on start up said 480 on the reading which the good zone is something like 180-350. This corrected when I pressed the throttle and went down to 250.

I don't really understand the injection readings but this was:
-0.72 mg/str Injection Quantity Deviation Cyl. 1
0.05 mg/str Injection Quantity Deviation Cyl. 2
0.45 mg/str Injection Quantity Deviation Cyl. 3
0.21 mg/str Injection Quantity Deviation Cyl. 4

Is this a good reading guys?

When the car is low tank it really judders a lot and restarting the engine always resets it. If the car has Redex it doesn't normally have a judder. I have started filling up with Vpower as I drive average of 500-800 miles a week motorway wise. The car previously had the injector unit changed at Docklands Audi however I have no idea what was changed as it didn't state and I bought the car without the service history, this was only found out when I ordered the duplicate service book. I need to test It when It next judders to see if I can see if it is an injector. Also I will check when I'm home from working in Europe to see if there is oil/black in my fuel filter.

What do you guys think?

Many thanks all that reply.

Stu

Car is a 2008 Audi A3 2.0 TDi 170 Quattro

 

[smurfworth]

if you mean juddering on idle then changing idle speed can also cure it

 

[stewpot1776]

yea it is only noticed on idle however I did feel it the other day on low rev acceleration across 2nd and 3rd but we're talking 1400-2000 revs. I did see a thread saying adjust it to 850/900 revs so could give that a go. Thanks Smurfworth

 

[Jackx1]

Mine does it too, I really don't think it's worth the effort and cost trying to resolve it.

 

[smurfworth]

yeah i get the same around the 1400 -2000 range, only on very light throttle though.

its never really bothered me, the pd lump runs real rough anyway, they all sound nasty, however its been faultless so I've never tried to fix the "issue" if you could call it an issue.

i'll only look at fixing it when something breaks haha

 

[stewpot1776]

you guys are right, why hunt to resolve a lump that isn't bringing alarm bells or engine management (yet & touchwood) i'll check and clean the EGR as I have never tried or really seen one. Redex is cheap and makes it smoother and surely it can't be bad putting a shot in every now and then

 

[Jackx1]

I find a tank full of shell v power usually helps smooth it out too.

 

[Bedders]

I'm convinced it's wear in the tandem pump! Mine does it at about 1700-2100 rpm. Had the dmf & clutch changed & still there. Had a whistly turbo replaced & it's still there. I'm going to risk a tandem pump as I think it could be fuel starvation but mine is under full throttle, low revs. Tick over on mine is fine & stable but chucks out black smoke on start up. Egr on mine was pretty clean at side of some I've seen.

It's a shame really that Audi won't admit that some of their tdi engines have been basket cases. Oil pumps smashing, juddering engines, some models even throwing rods through side of engine block & also crap plastic parts etc.

I sent Audi customer services an email this week to get them to take me off their marketing / literature list after my door handle fell off other day trying to get into my car to go to work. It'll be my first & last vag group car. I really do give up!

 

[percha]

Its the Ecu software. The corrections for the injectors are badly calibrated it seems at certain operating points.

 

[Bedders]

Its the Ecu software. The corrections for the injectors are badly calibrated it seems at certain operating points.

Not so sure about that....

Isn't the 140 bhp tdi all Bosch ie injectors & Ecu whereas the 170 bhp pd is all Siemens injectors & Ecu. I find it hard to understand how two software manufacturers can both get the same issue? Unless Audi themselves set the tune & got it wrong on both????

 

[percha]

Both are full Bosch as far as I am aware. So the 170 does the same? Interesting.

Mine has the judder in exactly the same point on the way home everyday at a certain set of lights.

The shot to shot readings would never be accurate reading due to sampling time of Vag com.

You would need INCA (development tool) and read ECU directly to get real values.

 

[percha]

OK yes it is Siemens I stand corrected.

 

[Bedders]

Judders are reported in both 140 & 170 bhp versions by all accounts!

 

[percha]

A friend spoke to VW about it and there was a paid SW update for it.

 

[tdi-man]

if yours is a 170 then there is a free injector recall on all 4

vw had an update for them but audi didn't ;(

normal idle speed for the 2.0 tdi bkd is 840 rpm

I have changed most things and still does it.

change idle to 800 - 810 rpm and judder on idle goes .

I have changed both fuel pumps, sensors, flywheel , turbo, gearbox, injectors, cars remapped, air flow, egr removed, new head,
the timings bang on , and found only when turn idle to 800 - 810 fixed it

 

[max69vk]

Judder can be caused by plenty of things however the ECU injector balancing on both the 170 & 140 is 'switched off' around 1600-1700 rpm. If your MAF is ok (I'm not too sure about your figures) then try changing the fuel filter. A ailing tandem pump won't cause the judder but it will feed oil into the fuel & fuel into the oil. Idle judder is controlled more by adjusting the rear cam rather than the front, check with VCDS that your torsion value is correct, then manually by eye adjust the rear cam to match the front cam positioning.