Help guys,I am having idle problems mainly a slight miss.
I've noticed fuel around and underneath a small black unit on the side of the fuel metering unit, it also has a two pin electrical connector to it and is held on with two torx screws.

Could this be the cause of my miss?
Is it dangerous to drive with this leak?
Finally what the hell is it and what does it do.

1990 560sel UK spec.

...but your car may catch fire.

Look here.

It'a an electro-hydraulic actuator which controls fuel delivery to the fuel distributor.

Thanks for replying, I have ordered a new unit and the O-rings, also one of the two main fuel lines has a small filter in a brass connector of which one side screws directly into the metering head.
This was full of rubbish to the extent that I cound'nt blow through it. Have cleaned it with carb cleaner. Not sure if it is the inlet or return.
Also ordered new O-ring for below metering head as this was perished.

O.k. I replaced the E.H.A. unit, since then the idle speed has increased by 200 r.p.m. on idle.(from 650 to 850)

The only other thing I found was a lot of rubbish in the in-line
filter where the line goes into the metering head. Can anyone suggest what could be causing the high revs.

By the way I tried the old E.H.A. unit which was originally leaking, thinking maybe the new one was faulty ,but the r.p.m. is still the same and to top it off the old unit doesn't leak anymore so I'm presuming by cleaning this filter it's relieved any pressure which had built up and caused it to leak in the first place.

Idle can be caused by any number of things on these cars. The regmine for fixing this is faily painless if time consuming. You mentioned earlier you had a slight miss as well. Here is what i would do personally.

Check all your wires and plug connectors.
check your fuel lines for dirt and replace your fuel filter, if necessary replace the injectors.
check your engine for air leaks and vacuum leaks
Replace all your rubber if it is brittle (cheap and easy to do)
Pull your plugs and make sure they all look good and correct, plugs can tell you alot about your engine and if it is firing okay.
Check your idle control valve and clean it up.
check your duty cycle and the eha there is an excellent diy article written by steve on this follow it, it works!

Do you have a hesitation out of curiosity when you accelerate from idle. If so check your idle potentiometer.
I don't want to be an ass but do a search on rough idle there is a huge amount on it in here especially for your car. I was in the same you where in and this forum has been great.
m

__________________
Martin Ingram
Colorado Springs
2005 320 CDI
2006.5 VW Jetta TDI
1991 560SEL (179000 Sold)
1972 280SEL 4.5 ('The Lead Sled' 320000 miles when sold.)
1972 220D (225000 when sold)

Hi guy's

Most of the things you have suggested I have done, but its strange that it should just go up like that.
There's a small tube bypassing the idle control valve, I have blocked the end from which the air travels into the valve and left the other side open and this has brought the speed down. But if I put my finger on the other side the revs go up .

that means there is a problem with your air distribution system. that line should not be closed. Search for leaks and test your idle control valve.
m

__________________
Martin Ingram
Colorado Springs
2005 320 CDI
2006.5 VW Jetta TDI
1991 560SEL (179000 Sold)
1972 280SEL 4.5 ('The Lead Sled' 320000 miles when sold.)
1972 220D (225000 when sold)