93 300D 2.5 starts fine, then bad idle, smoke, until engine get warm, then runs great
 

Just bought a 1993 300D from down south. Here in Colorado, when cold (30 degrees F) it starts, runs fine for 20 seconds, then begins the clunking nailing sound and has heavy smoking at idle.

Once the car warms up, it's just fine, and the car runs and idles very well.

I did notice a tiny fuel leak at two of the injectors as well as some air bubles at the base of one of the injectors.

My theory so far is that the injector seals at least need replacement. Any help or advice would be appreciated.

Also, where is a good place for seals or injectors and does anyone have a link for injector removal/replace procedures?

Thanks
Bob

try tightening the injectors first. it sounds like your diesel is acting like a diesel with a lot of miles on it

A friend of mine used to have a 2.5 and we did a lot of work on that car. There was a leak of some sort (hard black bubbley residue was present) on #'s 4 & 5 near the base of the injectors. We investigated further and found a leak had developed around the pre-chamber and compression was leaking out. You could actually feel it w/ your hand. We took one look at trying to pull the pre-chambers and refitting/replacing and he decided to drive it until it blew up instead. No idle issues there, but if your leak was worse it could be an issue.
As a comparison we look at another friend's 2.5 and he was also leaking a bit around #5, though you couldn't feel the compressed air. Common prob? I don't know.
Just my 2c.
-m-

I live in CO. as well and have owned three 1993 2.5 E300Ds. They all due this to some degree. Try this after you start the car, do not let it run until it starts running rough, drive away, in all of my cars this resolves the issue.
It is most likley related to your glow plug relay turning off the afterglow pre maturly,(should have up to180 seconds of afterglow), but not always, glow plug relay gets its info or outside airtemp from a coolant sensor but altitude compensation from the N4 black box, internal to the box, these cars were not completly tested at high altitude, so there are issues, you will find that if you change altitude often the car will go into the limp home mode( NO TURBO BOOST) just turn the car off and reboot the computer. Down at sea level the problem does not exist. There is a twelve page diagnostic procedure to check all imputs into the computer, if the glow plugs are good and the glow plug relay is good change the coolant sensor and hope for the best often it does not improve. Other than a couple issues this is the best diesel car Mercedes has ever built, good luck
Ron

It sounds like u need to replace ur timing chain, cam sprocket and tensioner. There is an FSM for this problem. That should take care of the smoking and shaking when cold.

The spline nuts have a rubber seal in them that is a dealer item. U need to replace that. I would suggest replacing all 5. Same amount of labor for chainging 1 or 5. All five may take 20 mins more.

procedures spline nuts
 

Any procedures out there for the timing chain remove/replace?

Where are the spline nuts located?

Thanks :sun_smile :sun_smile

i wouldn't be so quick to change the chain. Why would your car run well when it is warm if your chain or tensioner was bad?

I have a 93 300D 2.5L. It displayed the above symtoms. There is an FSM out for the 93's.

U may want to read the FSM.

If u want to get rid of the car, there is a fellow on this forum who is shopping for a 93 2.5.

FSM? procedures
 

Does FSM stand for Field Service Modification or Memo? Where do you go to view these?

Here's what I'm going to do:
1. Check the glow plugs and replace if necessary.
2. Tighten injectors if necessary.
3. Remove fuel supply to each individual injector to find nailing cylinder/ injector.
4. Remove/ clean or replace injector.
5. If problem persists, Look into the spline thing dieselbegel wrote about.
5. If problem persists, Try to find the FSM for the timing chain etc.
6. As time permits, replace timing chain etc.

The Beagle
 

Hey,

I too have a 93 300D, and the beagle is a great source for information. He has helped me tremendously. And you know the old adage..."if you ain't the lead dog the scenery never changes"...so until I get off the porch...I'll keep on following the beagle......just dont make abrupt stops beagle...Iceman