Engine shake!!


Registered User
Hi, this is my first post so please be gentle:salute: Ive been browsing through this site and find it very useful and have noticed there are some very talented people... technically talented!

I have a 2004 A4 tdi 130 which has begun giving me a few problems and was hoping you guys could help me out.... please.

1) On idle the engine shakes as if it missing, There is no fluctuation on the rpm

2) At approximately 1500rpm whilst driving i get a small judder/misfire along with a noise that sounds like two contacts rubbing against each other, maybe a metalicy kind of sound

3) On take off 1st and 2nd gear I leave an embarrassing cloud of smoke behind me. Not pedal to metal but calm normal driving conditions.

I know I maybe asking alot but i have been to the stealers who charged me for diagnostics only to tell me theres no fault codes showing. Any help would be greatly appreciated.


2003 1.8T Sport Ebony Black A4 Cabriolet
1)What speed does the dashboard show is idle ?
2) Have you checked the clutch to see if its slipping at all ?
3) Have you tried some injector cleaner ? The PD injectors are very small and high pressure and might need a bit of a clean out.


Registered User
1. could be your engine mount, they have an electrical connection, just have a look and see if its connected.. here's some guff I found out about the mounts.

On the later TDi's the mount has a solenoid which controls the rigidity of the mount..

the way the mounts work is that there is a fluid chamber with a plastic body in the middle of it, with small channel cut through it. this allows fluid from the top chamber, through the plastic body, to the bottom chamber. the bottom chamber is rubber lined and can deform under pressure. there is also an airway vented to atmosphere, with a rubber membrane separating the fluid from the atmosphere. a solenoid valve, controlled by the motronic, can open or close the airway.

below 1100 rpm (i.e idle), the engine vibrations are not enough to force fluid from the top chamber, through the passageway to the bottom chamber. the airway is open (solenoid valve open). the rubber membrane creates a soft cushion which absorbs the high frequency vibrations.

above 1100 rpm the soleniod valve is closed which blocks the airway and so "hardens" the mount (the fluid has nowhere to go). thus the mount is effectively solid.

the high frequency vibrations at speed are absorbed by the membrane (as in the idle case), while the more damaging low frequency vibrations cause the fluid to force itself through the chamber in the plastic body to the lower chamber, forcing the (lower) rubber chamber to distort - effectively absorbing the vibrations.

2. I had the same problem with my 2001 130 Tdi sport. I solved the problem by removing the injector wiring harness and tightening the spade connectors on each of the injectors.. It solved the problem straight away. The harness is located under the rocker cover, so its a DIY job. You could just buy a new harness for £41.20 + vat from Audi.. Hope thats of some use...

3. The injector harness might be causing the smoke if the injector isn't working 100%, try some injector cleaner and check the harness..

hope that answers some of your questions.


Registered User
Hey guys thank you for your quick responses. I think im just gona replace the injector wiring harness to eliminate.
Its white smoke followed by black the grey smoke
I have used injector cleaner to see if it makes a difference but no luck there, Ive purchased a product from Innottec called 'Turbo Clean' apparently its supposed to completely free the variable vane technology... just waiting on delivery.

This is what i intend to do over the weekend
1) strip all turbo pipes clean and check for splits
2) remove intercooler and clean
3)remove egr assembly and thoroughly clean

Can you suggest anything else????

Also 'Technics100' where can i find this mount solenoid and what can i do to repair it? - (I think i read somewhere its located near the powersteering resovoir but i think that was on a V6 tdi)


Registered User
I disconnected and plugged the egr valve today, drove about 15 miles down the M5 and all of a sudden the engine management light came on.
Whilst the egr was disconnected it stopped smoking and mis-firing which temporarily sorted the problem but now the engine light is on. Have'nt had a chance to plug in for fault codes yet but can anyone shed some light as to why this has happened? thank you in advance


Registered User
Fasttdi, I also have my EGR blcoked and never had any probs.

Here is the location of the engine mount (pic 1)

Pic 1


Here is a close up of the mount, the plug in on the back of the mount, just check its plugged in ok.

Pic 2


Here is a pic of the injector harness, it constantly sits in hot oil, I just took off each contact and cleaned it with contact cleaner and squeezed the crimps together, that sorted my misfire for me..

Pic 3


Hope that helps, it gives you something to do anyway...


Registered User
I think i may have fixed the cause to all the problems i was having! I followed the pipe down from the egr to the drivers side headlight and found two solenoids totally gunked up, I cleaned them as best as i could and the problem almost dissapeared so decided to purchase some new ones from dealer. And touch wood so far its been spot on, only done 20 miles as yet!


Registered User
When I disabled my EGR I ended up with a humming noise, which I assumed was the turbo spooling on idle. When I re-connected the EGR the hum stopped. I then used VAGCOM to minimise it's use. But then it still appeared. I've only got a small decrease in EGR usage from standard now.... Everyone else seems to be fine with this mod but my turbo doesn't seem to like it. A assume it's the turbo anyway.


Registered User
I would like to thank all who helped and gave diagnosis. very much appreciated. thank you guys