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[Sir Tigger KC]

So I had a diesel leak on the injector pump recently which I solved by replacing the seals on the delivery valves and all was good, was starting and running fine... 

However a couple of days ago I noticed that she's really 'lumpy' at tickover, a bit like it's 'missing', she starts and drives fine and when the revs are increased from tickover the 'lumpyness' disappears... 

Today there's been lots of rain for the first time in ages and I came out to see a huge slick of diesel going away from the front of the car (parked downhill)    I'm hoping that the water is basically washing all the oily crud from the undertray....    I've had a good look and can't see any leaks....

I've a horrible feeling that although I was ultra careful, I dropped a tiny bit of shite into the Injector pump when I had the valves off and its partially blocking an injector causing the lumpyness... ?

[Marks DTM Calib]

If it is and the injector is leaking into a cylinder then kiss the rings, bore and piston goodbye

[Sir Tigger KC]

Oh joy!! Thanks Mark for that cheerful news....   

I had a sift through the Mercedes forums and found a thread where the same thing has happened to a few, after changing the delivery valve seals but it didn't give a cause or cure.... 

I'll chuck a bottle of Redex in today and see if that makes a difference. 

[Marks DTM Calib]

Local diesel specialist should be able to do a quick test of the injectors for small money

[omega3000]

If it is and the injector is leaking into a cylinder then kiss the rings, bore and piston goodbye

Why's that then ? 

[Sir Tigger KC]

I think Mark means that if I've got crap into the fuel system and it makes it's way into the cylinder, it will score the bore and damage the piston and rings...... 

I've had another look around and have decided I need to change the diesel leakoff pipes as there is diesel in the injector wells.  Would this cause a misfire though? 

I havn't tried Redex or the likes yet, but it seemed a little better yesterday and was misfiring intermittently. 

[henryd]

I think Mark means that if I've got crap into the fuel system and it makes it's way into the cylinder, it will score the bore and damage the piston and rings...... 

I've had another look around and have decided I need to change the diesel leakoff pipes as there is diesel in the injector wells.  Would this cause a misfire though? 

I havn't tried Redex or the likes yet, but it seemed a little better yesterday and was misfiring intermittently. 

If an injector is leaking into the cylinder it will bore wash that cylinder and cause wear to bore and rings,I think thats what Mark means

[05omegav6]

Several later Transists have died that very way

[Marks DTM Calib]

It also ignites the diesel early in the stroke and often when its at the side of the rings

[Sir Tigger KC]

Ah OK Thanks!   

Maybe once I'd done the delivery valve seals and stopped the leak, then the increased pressure is causing the injector to leak?  In effect I've moved the problem on somewhere else.... 

Anyway it's been fine today, apart from the diesel slick which has reappeared in the wet weather! Must take the under-tray off and give it a good clean!! 

[omega3000]

I think Mark means that if I've got crap into the fuel system and it makes it's way into the cylinder, it will score the bore and damage the piston and rings...... 

I've had another look around and have decided I need to change the diesel leakoff pipes as there is diesel in the injector wells.  Would this cause a misfire though? 

I havn't tried Redex or the likes yet, but it seemed a little better yesterday and was misfiring intermittently. 

If an injector is leaking into the cylinder it will bore wash that cylinder and cause wear to bore and rings,I think thats what Mark means

Something else ive learned , i take it this only happens with diesel engines