Hello! I need some help from you experienced smokers. I have a 1st gen Cummins in my 89 d250. The engine has around 165,000 miles. It ran ok when I got it, low on power for sure though. However after a few weeks while towing a trailer it developed a knock. Light at first, then after a two or three miles it was to the point the truck needed to be pulled over. After the motor sat for a couple hours not running, it started right up and the knock was gone. However the motor was then running like a vibrator. I haven't played with it any other than to move the truck around the garage. But the engine is still doing the same thing, acting like its missing and blowing smoke at idle and with power. WAY more smoke than before the knock. There is fluid covering the drivers side of the block after running it, I haven't investigated to see what it is, and I can't tell where it coming from.

So breakdown: 1. Motor runs ok 2. then starts knocking 3. stops knocking next time it's started, 4. now blows alot of black smoke and runs like a vibrator. 5. soaks drivers side of block with unknown fluid

So if it was your truck what would you look at (for), and any ideas on what the problem could be?? Thanks for your help!

 

You need to find out what the fluid is that is leaking, likely it is diesel fuel or oil.
"Down on Power" can be anything from a distressed fuel supply due to leakage, to a bad lift pump, to the injection pump is faulty.

As far as the smoke, is it a really light blue-ish-white, or is it black?

If it's white, it's timing or fuel supply related.
If it's black, you're dumping a lot of fuel in, either by an injector pump malfunction of sorts, or a turbo not pushing enough boost for the fuel you're moving.

Either condition, starved for fuel, or too much fuel, can cause the engine to miss.

The knock MAY be related to the fueling, or lack of, but not highly likely.

Mark.