e300 td timing mechanism

[runningman]

1998 E300 td, 49700 genuine miles.

Has anybody out there ever replaced the fuel pump advancement/retard timing mechanism, which is located on the back of the pump drive sprocket. As i have a gut feeling that mine has somehow jammed in the retarded position following very (suddenly) bad starting one morning (knocking its head off).
The only way i can stop the diesel knock is to advance the pump by rotating it 2 - 3 mm towards the block.
EVERYTHING regarding the fuel system has either been checked ok or renewed.
Done a liqui moly diesel purge and the engine ran like brand new, until i ran it on normal diesel then the knock returned.

Before i advanced the timing the engine knocked at idle up to 1250 rpm but cleared as the revs increased. No smoke, starts first time but power feels a bit flat.

When i advanced it the knock dissapeared, engine ran smooth as silk, no smoke, starts first time, the lost power has returned and MPG is better.

How easy a job is it to change it? and are the're any pitfalls i should be aware of?
Im very handy with the spanners.

Regards

 

[Olivier]

Why d you want to change it if the car run OK now?

 

[runningman]

Olivier.

I know the engine runs ok but the problem still exists and needs to be fixed. im just thinking, thousand of miles down the road it could be bad for the engine.
I just want the engine to run like it was before.

 

[Dieselman]

Try performing an oil flush to see if it is jammed or the oilway is blocked.

 

[runningman]

Dieselman

done a diesel flush a while ago and it didn't do anything. Changed the oil again about 1000 miles ago and its still clear as the day I put it in the engine, engine is spotlessly clean.

 

[runningman]

just surfing the net and came across an article about the 606 engine fuel pump being fitted with Pulse Width Modulation control. There is also a youtube video showing a 606 engine running very poorly (fluctuating revs) and sounding very knocky at idle.
It aslo mentions that these PWMs can go faulty and will make the engine sound like its running advanced.

Sounds alot like my problem.

When i advanced the pump on my car the knock went away, when actualy the knock should of got worse, would you agree?

Ive got a spare pump so im going to remove the back of it containing the PWM and fit to my car. Ive looked at a picture of it on the web and it looks like it just separates. Can someone clarify that please.

Regards

 

[Dieselman]

The timing is mechanical only, the electric control is for fuel volume only.

 

[91dm]

Your problem sounds similar to one I had, hard knock sound upto and worse at 1100rpm. I found a blocked oil hole in the centre of the pump sprocket.

The back of the pump does split apart. I doubt the problem is with the pump itself.

 

[91dm]

Where abouts are you?

I have a pdf somewhere for removing the pump/timing marks if its any help?

 

[runningman]

91dm

Im just 2 hours up the road at Carlisle, a pdf would be of great help. I have got a pocket manual but gives limited information. Trying to get info on these cars is tiresome doesn't, seem to be much out there. I will send you my email if thats ok.

Regards