300 sdl low idle skip/miss up to about 2500 RPM
 

I have a 86 300 SDL that has a skip/miss at low idle up to about 2500 rpm's.It has been sitting for about a year,any suggestions.. Injectors,glowplugs ?

Does it skip/miss when fully warm?

If you haven't driven it in quite awhile, the vehicle should be driven at least 500 miles with a good dose of PowerService in the tank.

Then reevaluate it.

I would try to isolate which cylinder is missing by loostening the fuel lines one at a time with it running, then switch the injector for another to see if the injector is the problem or the cylinder.

Then if its the cylinder i would run a compression test.

A diesel is pretty simple, its either lack of compression or fuel that is causing the problem. I am betting its compression.

Tom W

So would I. You have checked your valves for clearance and adjusted them right? This is one of the easiest ways to drop compresion in one cylinder. A burned valve won't hold compression either. The only cure for this if this is the case is a valve job.

I'm very certain that he did not check the valves.

I'm also quite certain that the valves are not the source of the problem.

You could be right, but how would you know for sure unless you check them? When I bought my 240D, I got it cheap because it had a miss. The owners sone had just adjusted the valves and made on so tight, that cylinder could build up compression. Luckily for me, they sold it thinking it needed some serious engine work!

They didn't drive it like that though.

It's an '86 SDL, isn't this a 603 (hydraulic lifters), therefore no adjustment.

Is Brian clairvouyant? Could be or maybe you can't adjust the valves on an OM603 engine.

He's just one of the few who remembers that they actually built diesels after 1985. ;)

OOPS! I didn't know these were not adjustable.:o I've never owned anything built by Benz that didn't have a Cast Iron motor and a 617 in it and I thought the SDL came with this engine. Is this the 6 cylinder with the headcrack problem?

There was one of these in my neighborhood for sale, but if it one of these, forget it!

They only have a head crack problem if you over heat them. If you drive one that is performing correctly, you may change your mind about them.

To all that responded thank you very much,i had to register under a new user name..not very good with passwords,e/mails etc..I was installing a new radio today replacing the Becker and it ran perfect.? i noticed the other day when it was missing it would puff black smoke..Does diesel fuel get old ? thanks again for all the responses

Brian "PowerService" is that something i can readily pick up locally at a NAPA or Autozone..the car runs extremely strong compared to the 5 cylinder i had..when it gets to running temp it nails a little,i thought it my be a weak spring in the injector..thanks afain