Juddering when started!

[Humair]

Hi All,

Been a while since i've posted a thread, must mean the cars been running ok...yeah right....

Ok, got a new problem which is confusing the s**t out of me! When i start the car...cold start (off course!) the whole car judders for a few seconds then is all normal.....also at the same time when it idles i can hear a slight knocking noise...(vanishes when you slightly rev) a tapping noise, but i know its not the hydraulic valves....even after using the cleaner twice! need advice, as have been told by my mechanic that it could be one of the pulleys...but that still doesnt answer the question why it may judder...there was one thing i done, with the engine switched of, i shock the car from the front, i.e. bouncing it from the suspension and could hear a noise of something knocking....and my mechanical skillz not being wot they were, when i had a golf...brings me here again....simply because you people know FAR FAR more than me....so please enlighten me with your knowledge...b4 i have to englighten my mechanic with my wallet!

Many thanks

Humair

 

[Humair]

Sorry its a 300 CE, 89 model, with 130K on the clock....

 

[Stevie A]

Try feeling behind the crankshaft pulley to see if your vibration damper disc / harmonic balancer disc is loose / worn. A high speed constant vibration at idle would be noticeable if disc gone.

Also check belt tensioner vibration absorber as this can rattle too. It looks like a small hydraulic ram and it's on front of engine linked near belt tensioner. Try harmonic balancer disc first.

 

[Bolide]

I'd say this was caused by knackered engine mounts plus a bit of piston slap plus a bit of hydraulic lifter pump-up

The clue to whether the engine mounts are worn is what happens when you turn the engine off. If you get a big vibration through the car as the engine stops the mounts have gone. On the bigger engines & diesels it's like a left-right shake. Think of a horse tossing its head and you get the idea

Nick Froome
www.w124.co.uk

 

[Stevie A]

I agree with Bolide too, another possible cause is the mountings.

 

[Humair]

Thanks guys, will check wot you have told me tonight! make a lot more sense....will get back once have had look....

Thanks again!


Humair

 

[Humair]

Right, i had a look last night and this is the story....

When i switch of the car there is no movement at all.....when i start the car, it starts fine, then the revs drop quickly, to a point where it either swtiches off, or just holds it and stays on, and when it does stay on thats when i get a slight juddering....until it levels out, and all is normal, could the pulley tensior cause this issue...??

Also how and where do i check for the harmonic balancer disc?

Many thanks agian

Humair

 

[Stevie A]

If it was a constant fast vibration at idle speed then it could be the harmonic balancer. I don't think it is that though going by your updated post.

Sounds almost like the engine is missing a bit at start up and this causes imbalance in the engine and the vibration.

If the tension absorber is gone I think it would rattle all the time. Same with the harmonic balancer. Loose / worn engine mounts would be noticeable when starting / stopping engine and changing gear under load.

Missing at start probably means you need something simple like new spark plugs / fuel filter etc

 

[kid-jensen]

My money's on plug fouling for the first few seconds until it clears.

If the plugs haven't been changed for a while, might be worth doing. If they'e newish, check they're not getting drowned with oil......