2001 A4 1.9 TDI Engine Shaking/Wobbling

[monty478]

Hi Folks,

I have a 2001 Audi A4 1.9 TDI and recently the engine has started to shake/wobble quite a lot on idle once the engine has warmed up. When the car is started from cold its fine no shaking/wobble on idle at all, after its warmed up say 15/20 minutes on idle only it starts rocking from side to side.

If i increase the revs on idle just ever so slightly the shaking stops and engine is stable, pushing the clutch up or down out of gear makes no difference. If i have the car in gear and bring up the clutch the engine stops shaking and becomes stable. Whilst driving the car its absolutely fine and doesn't shake or vibrate at all.

I've had a look around the engine and the egr valve is leaking and has been dripping on the manifold, I've taken the cam cover off and where the injectors are there is oil there and the electric connections that connect to the injectors have a slight covering of oil. Should there be any oil where the injectors are? I've attached some images.

 

[sumo]

Yes the oil on the connection is OK, from what you say I would think about replacing the injectors loom as this can cause issues.

 

[pauldazzle]

+1 for injector harness/loom.

 

[monty478]

In the first picture you can see quite a lot of oil sat there its quite deep, is that normal? Also if the issue was with the harness/loom then why does the shaking/wobble stop when the revs are increased?

 

[pauldazzle]

Oil is normal. Oil isn't conductive so doesn't effect the injector contacts.
Poor contacts on the injector harness is the usual cause, it's worth unclipping them cleaning them up, & try opening up the contacts so they make a firmer connection when pushed in. Doesn't always work, but worth a go.
You may be getting a better contact when revving engine, or the increased current is arcing the poor connection.

 

[Mothy69]

Dmf? (If you have 1)

 

[Mr Spaghetti]

Mine developed a wobble, and it was down to the "one way bearing" on the alternator. This is supposed to dampen speed differences, and works like the ratchet on the rear wheel of a bike. I just backed off the tensioner on the auxiliary belt, and rotated the alternator pulley, it should rotate one way and turn the alternator, and freewheel the other way. Mine seized up at about 60k, and caused the belt to twang around, and made the idle rough.

Pete

 

[SemedoB6]

I had this happen to me and I bought a new loom from audi from 70 odd quid and after fitting the loom the car was good as new.
Taking off the old loom you'll probably break it (not important as this is likely to be the fault).
What I did with the new one was put it in the oven heated up @ 60° just do the plastic bar becomes bendy enough to slide in through the holes without breaking it..
Just don't forget the loom in the oven as 15m will do the job. And before connecting the loom to the injectors make sure to clean the connectors.
Saw this trick on another forum and was reluctant to out a new loom in the oven, but I'm glad I did it because that plastic is really stiff and the oven allows you to work it until it's in place..
Hope it helps.

Sent from my LENNY using Tapatalk

 

[desertstorm]

As above first check the one way pulley on the alternator very common issue and easy to diagnose. If that's OK then the injector harness would be my next point of call after checking with vcds for fault codes as sensor issues can cause poor running. You may have intermittent fault codes for injector issues which would point to a harness issue