New used truck....w/ problems

[mudracer80]

I just bought a 1993 3/4 ton 6.5l diesel for 800 bucks. It starts up and runs but when you first start it it smokes like crazy!!! white/ gray pure diesel smoke. It also rattles and knocks quite a bit louder then I would think it should, it runs so rough it shakes the whole truck. It lines out and runs better after a few minutes but still has a miss to it almost like it down a cylinder. Last but not least while driveing it down the road it will sometimes not rev past 2000 rpms no matter if you foot is flat on the floor or not.

I have changed all the injectors, fuel filter, oil pressure sensor, and oil. I dont know enough about these motors to go any farthur, any help would be much appreciated.

Thanks in advance.

[6.5 Detroit Diesel]

congrats on the truck, is it a five speed?

how are your glowplugs? when were they last changed?
after that, you are probably going to be looking at a new injection pump. :eek:

[DaveBr]

Check to see if your lift pump is working. Looks like a typical GM gasser fuel filter with 2 wires coming out of it. It is located inside the frame on drivers side about middle of your cab. When it is running it sort of sounds like a cat purring. This is a common problem with these trucks.

[DmaxMaverick]

Welcome aboard!

As suggested, verify fuel delivery during the start and run conditions.

Then, replace glow plugs and injectors, and get it properly timed (any competent 6.2L Diesel mechanic can do this by ear, in 15 minutes). Don't bother with a compression test unless an overhaul is an option you are entertaining.

[mudracer80]

Thanks for the replys

I will check the lift pump out this evening. The glow plugs may need to be changed, I'm really not sure what all has been replaced by the previous owner. I really appreciate the help, I am clueless on these motors but this site is awsome, a fountian of info.