I have a 1982 300SD with 228,000 miles on it. The engine was running excellent until the next time I started it and the engine shook and sounded like one cylinder wasn't being fully efficient. If you put your hand at the end of the exhaust pipe, you can tell there is a miss in the firing order, and it puffs black smoke that smells quite raw. Anyway, I opened the fuel lines while the engine was running and determined that #2 injector wasn't doing it's job. So, I replaced it, but no change. So, I switched the #2 and the #4 injectors, and still no change in the #2. I am at a loss for what to do now. Is it in the injector pump? Or the part of the injector pump that supplies fuel to the #2 cylinder?
Yes, diesel is getting to the injector. However, I don't think ENOUGH diesel is getting there. When you loosen the fuel line to each injector, they all spray fuel up and out toward your face except the #2. The #2 line sort of dribbles out, and after closing the line, the engine tone does not recover, eventhough it still doesn't run properly. Whereas all the others, after closing the line, the engine tone goes back to what it sounded like before you opened the line.
That certainly sounds to me like a problem with the diesel pump.
The only other possibilty all be it not very likely is that there is a blockage in the pipe from the pump to the injector. I would check that first, but I think you have a bad pump[xx(]
If your pump is bad, take it to a very respectable shop. The pump cannot be fixed at home....usually not even in a shop. Also, it is a real bear just to R + R the injection pump...specially if the engine is in the car! Setting the timing is a more of an art than a science....Should I go on???
Its been a while but I think a reman. pump is $800-1200 plus install. Not a small job...
Hopefully your pump is OK... Does it miss while driving??under load?? or only at idle??
Is there any unusual clacky ity clack sound??
Maybe change out the fuel filter and examine the old one for signs of water contam...i.e. rust.
I used to use this trick as a last resort...not because it is dangerous.. just because it sounds kind of snake-oil-ish:
Since the fuel filter was removed for examination, replace it with a new one....but before you thread it on, fill it with Ford ATF...or a Ford compatible ATF. Anyway, thread it on, start the car and run the ATF through the system...The high detergent in the ATF can sometimes free up a sticky injector or other fuel system component.
I will probably take a beating from some purist MB guys here for that little trick but I've been working on and around commercial diesels for a while and have had success a couple times....If it works, great! If not....time to open the wallet...or the tool box....or both[:(!]
bblood, thanks for that info. If it matters or not, the engine only misses at idle, and it slightly knocks and nails around the #2 cylinder area only. I listened near the #5 cylinder and it is definitly coming from the front cylinder. But, I can drive down the freeway normally, and cruise through town and the engine runs fine, it is just at idle that it acts up. When you get the rpms up, it sounds fine.
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