Engine Misses ?????
 

I just got back from New York with a 83 300SD. The engine misses really
bad when cold. After it warms up it's not that bad. But still misses.
I am guessing its a bad injector, but thought I would ask you guys what
you think. It also shifts hard from 1st to 2nd and flares from 3rd to 4th?
Thanks. Jason

Here is what my suspicions would be .........
 

"Misses" or nailing while cold, I would very much suspect a defective glow plug. And depending on how long it has been that way, may have caused some carbon build-up.

Changing out the glow plug(s) and cleaning the injectors in a dunk tank of carburater cleaner might be the ticket. That's what I would try first anyway.

It misses. I think the fuel timing is off alittle too.
Thanks. Jay

how long does it take to run smoothly?

tom w

Possibly a broken prechamber ball. Had one break loose from it's mount inside the prechamber while driving and caused a miss at normal operating temperatures. This was on a '60's model but would think the same thing could occur with an '80's model as they are designed the same.

how long ago since the valve clearences were last attended to ?

There are several things that could cause it. But I would test the glow plug circuit and ohm the plugs out first, valve adjustment, timing check. Then report back. Lets eliminate those items first.

http://dieselgiant.com/glowplugrepair.htm

http://dieselgiant.com/valveadjustment.htm

Targa,

If the GP pass the resistance test, do the following:

Immediately after U start the engine and it is mis-firing, try to isolate a mis-firing cylinder by loosening the nuts on the top of the injectors one at a time.

If U don't notice a difference in the engine speed or sound when the nut is loosened, that is the cylinder that is mis-firing. A slight amount of fuel should leak out when U loosen the nut.

If you find a definite cylinder that is mis-firing, switch that injector with one from a good cylinder. If the mis-firing moves with the injector, its the injector that's bad. If the mis-firing doesn't move, then there is something wrong with the cylinder. It could be the ball pin or low compression from a leaking valve or rings.

If the engine mis-fires after its warm, is not a GP problem.

P E H

Thanks everyone, I am going to try the things listed and report back.
Thanks again, Jay