need help with 300sd
 

Hi everyone, my brother in law recently bought a 93 300sd with a leaking ip, last weekend we were working on the car to replace the delivery valve seals. When we stated the car it felt like it was only running on 5 cyl instead of 6 and blowing alot of black smoke, I started to loosen the diesel hard lines on top of the delivery valves and all of them made a difference in the way the engine ran except for the fourth one? Any ideas what it might be? Thanks Hugo.

Sorry I would only be generalizing on your vehicle, but
 

Welcome to the forum!
black smoke indicates unburned fuel. you might try swapping #4 and another injector and see if the dead cyllinder moves.
John

We tried doing that and the problem remained.

Maybe the o-ring or washer didn't sit properly in the delivery valve. It's a lot of work but you can redo those seals to be sure.

Sixto
... stay tuned

I'll try it and see what happens.

I agree with Sixto.

It's too coincidental that the problem surfaced right after you did the delivery valve seals. It's not uncommon to have one of them not seat properly.

What do the delivery valves do anyway? I guess I'm confused with the delivery valves and the injectors.
:dizzy2:

Me too.
 

I also wish more info on delivery valves...
John