W210 Diesel pump timing saga (THOUGHT)

[Tinytots]

With reference is my previous thread.
Is it possible that the diesel pump timing could out by 180 degrees even though the engine timing is spot on and the pump was locked when fitted?

All thoughts greatly appreciated. Shane.

 

[Druk]

Yes, absolutely. That was suggested in a previous post . The cam cover has to be removed to ascertain if the engine is on firing stroke on No1 cyl before the pump is inserted. There are timing marks on the cams which have to line up. Another -less reliable- method is to remove No1 glowplug and determine (by feeling compression) if the engine is approaching firing stroke on that cylinder. However, you run the possible risk of snapping the glowplug doing it that way.


Post #6 here...http://www.mbclub.co.uk/forums/engine/163445-diesel-pump-removal-timing-settings.html

and here...http://www.mbclub.co.uk/forums/part...ng/163163-timing-degree-remove-pump-w210.html


ps. Dont think much of your 'mechanic' :fail




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[Druk]

Can't now edit the previous post so let me try and explain.

What you have is a 4 stroke engine. By definition this only fires (injects, combusts, ignites..call it what you will) every second revolution of the crankshaft for any given cylinder. On the next full revolution it's on it's exhaust stroke on that cylinder. So, although you say that possibly the pump is 180deg out, in actual fact it is the engine that is possibly 360deg out. ie, on the exhaust stroke of No1 cyl. Because of the need for the injector to fire only every second revolution the injection pump is geared to run at 1/2 engine speed.

Another way out of this would be to simply try the thing with the engine timing 360deg advanced from what it is just now. If that's wrong no harm will befall.

Turn the engine to it's 14d ATDC marks and so the pump locking pin can be seen to be able to be inserted into it's slot BUT DO NOT INSERT!. Rotate engine through 360 deg until 14d ATDC is again showing. Remove pump (NB..without inserting pin). Rotate pump shaft through 180deg and insert locking pin. Remount pump, remove pin, and try engine for running.
Note well that I'm saying only rotate engine with pump in place. If the thing is turned without the pump in place then there is a chance the timing chain will jump a tooth or two and then the timing really is out and will have to be reset from square one. Lets us pray your mechanic hasn't done this..



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[Tinytots]

Thanks mate. You have no idea what this has been like. MB specialist????????????
I took the cam cover off and he set timing at 14o ATDC and both dots where lined up.
He locked pump and fitted.
On engine start the car was, on 6 cylinders at idle, no power when drive selected, revving engine is lazy and spluttering and top end knocking.
He thinks that the diesel pump its self needs a further 180o rotation prior to locking and fitting, but if there is only one locking pin inside the pump I can't see how this would make any difference, as it wouldn't be a 180o rotation to lock it would be a further 360o.
Would it make a difference setting engine timing at 15o?

Druks I'm at my wits end with this. At one point I was thinking of just scraping the car, but I love it and its in really great condition and I have plans of making it one of the cleanest E300 there is.
I don't know what else to do.
I'm very grateful for all your help. Shane.

 

[Tinytots]

Thanks mate. I'm going to the garage now. I've got the above information printed out and taking it with me.
Keep ur fingers crossed for me.
Thanks again mate.

 

[Druk]

Well, if the timing marks on the cam were OK then that's my theory busted. Was the car running OK before the pump was changed. What were the original symptoms?

You're also correct in that turning the pump through 180 will be no good and through 360 it's just back to the start.

Try retarding it to 15 if you like. It shouldn't make that much of a difference being only 1 deg out. For instance I advanced mine through 4 deg to try and stop it smoking and that had very little effect on the actual running and it's now locked at 13.
Turning the adjusting screw clockwise retards the ignition point. You only have to slacken the three front pump bolts and the rear bracket bolt for the pump to rotate slightly.