E300D surging on tickover

[philiggy]

My E300 diesel is surging on tickover, the more load I put on the worse it gets, so putting the lights on makes it do it slightly where as putting the air-con on make it surge up and down really badly.

Is this electrical I've just changed the ovp relay, sadly that fault was hiding this one

Phil

 

[Dieselman]

It's something to do wit the idle stabalisation unit on the back of the pump. It seems as if it's not damped properly.
iirc there is a damper bolt in the back of the pump unit which is meant to steady the rack.

 

[philiggy]

It's something to do wit the idle stabalisation unit on the back of the pump. It seems as if it's not damped properly.
iirc there is a damper bolt in the back of the pump unit which is meant to steady the rack.

Thanks Dieselman, is this electric, vacuum or mechanical thing I'm looking for

Phil

 

[Number_Cruncher]

You can read fault codes out from this ECU, on pin 4.

The "tool" you need can be made at home, and it's construction and use is described at the foot of this page;

http://pages.prodigy.net/jforgione/MB_X11.html

One of the sensors which this system relies upon is the coolant sensor, which is located towards the rear of the cylinder head, under the manifold. This is the one part of my engine loom where the insulation had degraded.

It's possible to check the temperature sensor remotely, via the 12 pin connector which I mentioned in the other post. The temperature sensor resistor is connected between pin 8 and terminal 2, you should get about 2500 Ohms at 20C, falling to about 200 - 300 Ohms when hot.

Edit: forgot to say - I wouldn't go looking for things to twiddle on the injector pump until I was *sure* there wasn't a simple fault elsewhere.

 

[gary121159]

Electrical fault, Hi I have my Drivers front head light side light not working, and my dashboard light is out and so is my driver side rear light also, not bulbs? any ideas where to look please?

Gary

 

[philiggy]

You can read fault codes out from this ECU, on pin 4.

The "tool" you need can be made at home, and it's construction and use is described at the foot of this page;

http://pages.prodigy.net/jforgione/MB_X11.html

One of the sensors which this system relies upon is the coolant sensor, which is located towards the rear of the cylinder head, under the manifold. This is the one part of my engine loom where the insulation had degraded.

It's possible to check the temperature sensor remotely, via the 12 pin connector which I mentioned in the other post. The temperature sensor resistor is connected between pin 8 and terminal 2, you should get about 2500 Ohms at 20C, falling to about 200 - 300 Ohms when hot.

Edit: forgot to say - I wouldn't go looking for things to twiddle on the injector pump until I was *sure* there wasn't a simple fault elsewhere.

Thanks for that, it looks a bit over my skill level though

Phil

 

[Number_Cruncher]

>>it looks a bit over my skill level though

If you have a multimeter (cheap, basic, digital ones are available now for under £10, ideal for the occaisonal DIYer, see the link below), then, checking the temperature sensor is a doddle - 5 minutes of a job.

http://www.maplin.co.uk/Module.aspx?TabID=1&ModuleNo=37279&doy=31m7

Rigging up the fault code reader is also not too difficult once you've got the parts (£2 tops from somewhere like Maplin).

 

[philiggy]

Thanks dieselman

It's something to do wit the idle stabalisation unit on the back of the pump. It seems as if it's not damped properly.
iirc there is a damper bolt in the back of the pump unit which is meant to steady the rack.

Thanks Dieselman took it in for a for a service today, they turned the adjuster on the back of the pump out 1/2 turn and it sorted it

Phil