Recently I obtained a 94 F350 XLT 4x4 IDI Turbo Diesel. The engine has a knock usually from start up and does not go away. I have started it on occasion and the knock wont be there at first, but will come in after about a minute. Most of the time it knocks right on start up. I have noticed that some times the knock will be quieter than others. It also black smokes heavily on acceleration. I replaced the nozzles and it did not change anything. I checked the timing marks on the cover and injection pump and they line up. I'm kinda stuck on it being a fuel knock with the way the sound changes from time to time and with the smoke issue. Is there any way to test the injection pump? Any help would be great.

 

Did the truck sit for a while before you got it? Does it seem to run fairly decent? Is it hard to start?

My injection pump timing mark sits about an 1/8 inch to the left of the timing mark on the motor.

Where did you get just nozzles? I had to buy a set of injectors for my last IDI and could never locate just nozzles.

 

Yes, the truck had sat for awhile. A little over a year. The truck runs great it also holds great oil pressure and no its not hard to start. It was when I first got the truck but that was due to inop glow plugs and bad battery cables. I have since repaired that. Sorry for the the bad terminology on the nozzles I have always called mechanical injectors nozzles (sorry bad habit) they were the whole injector. They were stanadyne injectors new not reman. I went out earlier and cracked the injector lines loose, the knock does not go away. So now starting to believe it is a rod or main bearing but still doesn't explain the smoke. The truck has 287,000 mi so it wont surprise me if I have to go through it.

 

I had a 240d benz with a stuck ring that knocked pretty good after being started with starting fluid a time or two. It eventually went away. It seems like a rod knock would be pretty consistant and pretty heavy at startup.