pre-start coil light sometimes doesn't come on?
 

When I turn my key on, sometimes the dash "coil " pre-start light does not come on. Is this a light connection problem or does it signify starter problems? Thanks.

I presume you're talking about the glow plug light, on either the D or the SD.
Do a search on that here. We've had a lot of glow plug light (or indicator) discussions.
Mine never comes on, so I think I just have a bad bulb. It always start fine, so if it works, don't fix it, so to speak.

I've had the light fail on two different 617 engines. Both times they were difficult to start when the temperature dropped down to about 32 degrees or below. So, it was definitely not the bulb. Turns out that one had one bad glow plug and the other had two bad glow plugs. The one with two bad glow plugs absolutely refused to start until the temperature warmed up a bit. So, temperature will tell the tale if the light is out.

I usually put my foot on the accelerator pedal about half way when starting cold after the glow plug light goes out. My car will die if I don't. I'll drive with one foot on the accelerator pedal and one foot on the brake until I feel it is warmed up enough. I don't have the patience to wait how ever long it takes to warm up before driving. I wish it had a throttle cable like the non turbos. I've thought about adjusting the idle to run better cold but then it would probably idle too high when warm. And this is with all new glow plugs.

This sounds a lot like a rack damper pin that's been turned in too far. You might try backing it out a turn or so - I guarantee that you'll start easier when cold. The trick is to make sure you don't take it so far out that the car shimmys and shakes.

Rack damper pin, what's that? Maybe that'll keep my left foot of the brake pedal. Not to sound like I don't know anything about engines, but I don't know everything there is about diesels, now gas engines that's a whole other story.
~DJ

The rack damper pin on your OM617 is at the back of the IP, near the oil filter housing. It's a 12 mm brass colored bolt (or silver if you have the old style) inside of a 14 mm locking nut. What you want to do is loosen up the locking nut, then back out the brass bolt a turn or so. The purpose of the bolt is to dampen a natural shake that the engine has, so if you notice a shake at warm idle you've backed it out too far. If the pin is too tight, the engine is harder to start cold, and requires constant fuel to keep from stalling until it warms up. BTW, if you have the silver colored bolt, you should upgrade to the newer brass colored one - they're only $20 or so. The old one may have failed, and perhaps that's why it's turned in so far.

Thanks very much for the tip and how to do it. This will be at the top of my "things to do" list for the car.
~DJ

The light was talking to me. I check resistance on the gkow plugs, replaced the dead #2 plug and all is well. Light now works. Let me tell you, it's no picnic to replace the #2 plug. It took me close to 1 3/4 hours with all the injector lines in the way.

rack damper pin
 

I had the same experience having to push the pedal down when starting cold. Turns out the PO had the pin all the way in. Took it out and it is still good (the tip is convex shape). Adjusted with hot engine. Search the archive for adjusting procedure.

After adjustment, the cold engine starts and idles without the need to push the pedal.

Well I tried backing out the rack damper bolt and it didn't seem to help. It found it turned all the way in and I backed it out a little at a time to the point that it looked like it was almost all the way out but it made no noticable difference. What exactly does this bolt do and is it attached to anything? Is it difficult to change?
~DJ