OM603 Extended Glow Plug setup installed.
 

Well, since my SDL runs again (FINALLY) I opted to install the factory GP setup found on the later '90+ cars.

All you need is:

Relay: 012-545-90-32
Sender: A-008-542-56-17
1 - clip: 015-545-96-28
1 - pin: 002-545-99-26
1 - pin: 003-545-26-26
1 - clip: 011-545-71-28

My relay was used and cost me $40. The sender is around $30 and is the most expensive part of the mix next to the relay. The other bits are less than $10.

Just run a new wire from the sender (has two pins now versus one) to the new relay's "T" connector. For TIMED I assume :confused: Anyway, it's very simple as the relay bolts right into place of the original. Best way to get there is to remove the IP lines. It's a 19mm socket for the sender.

With an initial glow of about 8-12 seconds plus this, my SDL will start and idle very nice in the high 30°F temps. Was it worth the sub $100? YES. No stumble, no burping, etc.

I recommend this 100%. :)

Thanks for the part numbers. I got everything and am going to install this week. My question is where the new sender goes. Does it replace the one below the #3 injector/glowplug or the one by the thermostat? Thanks.

Yes, it replaces the one under the intake. Best way is to either pull IP lines or the cruise servo.

Is this only for a 603? Or will it work on the 617?

The 603 needs the benefit of the setup. The 617 does not. The differences in the head make the 617 idle perfectly fine on initial startup.

ah so that's it. my 617 idles so nice when cold and my 603 idles as if it's about to lock up and throw a rod at the same time... even when it's hot outside. after a few minutes it's perfectly fine though. so I assume that's normal?
how did mercedes sell these cars when new then?

They probably had considerably higher cranking cylinder compression when new and not at 200,000 miles.



I agree, the 617 simply does not need the setup. Maybe if your GPs were all shot and you had the extra cash for the relay... then I'd consider it. I may next time I do GPs in the SD. :)

Yep, I'm a bit frustrated with the '86 as well. I do give it 30 seconds of glow and then run the rpm up to 1500 immediately. This eliminates the problem.

I would "assume" that they behaved better when brand new........but........I can't be sure of it.

One interesting note:

I started the '87 for the first time in six months. I expected the worst. I gave it a glow of 15 seconds and turned the key.

It runs within one second and there is no characteristic banging, missing, or coughing that is common to the 603. Shocked the hell out of me to the point that I kept the key in the start position for about 1 second after it was running.

Note, however, that this engine has a #22 head with angled injectors........although it does have 180K on the odometer.

The differences between the two 603 engines are striking..........

How recent was the head install on it? If I recall, it's quite low.

Yes, it doesn't have many miles on that head. He did the head not too long before he sold it. It's really an excellent vehicle. I need to get the a/c running on it and I'd like to take the SD off the road for awhile.

I have a casting 14 head on my SDL and I have never had any missing issues in the 40K miles I've driven it. Ice cold or whatnot it starts and idles perfectly smooth with 280K showing. Its parked now, anyway.

But yeah. Some are like this definitely. My 350SD 3.0 will stutter a couple of times when started cold. Needs to be revved to about 1400 - 1500 rpm for maybe 5 seconds then all is well. Runs like the dickens when warm, however.

To some extent I disagree, my 84 has the afterglow and it starts beautifully in the cold, my 80 has the old style and it stumbles a bit and once required 2 glows in sub 30 temps, Engines are similar in milage, maintaince, and compression numbers.

Hrm, interesting as it has 180k. My SDL has oil leaks I assume through the valve seals potentially guides... you can see it down the block. :o I may jerk the head and install my rebuilt No 18 here.

Not normal at all IMO.

603 #1: 188k, #14 head: Cold start with minimal glow, smooth, no stumbling nor smoke

603 #2: 245k, #14 head: Cold start with minimal glow, smooth, no stumbling nor smoke.

Niether of my cars have any afterglow mods, glow plugs are not recent. #1 glow-plug light extinguishes in less than a second, haven't troubleshot it yet but it starts so well I'm not in a hurry to find why it goes out early.

Ironically my 602 had to glow for a while, would still stumble a bit, would let it glow a little after the light extinguishes to get a smooth start.

The 603 started very well when new, if it's cold out and not plugged in, you're going to get some rough idling but not at 50F or more. It it starts rough, something or some things are out of spec., no big deal but it's not a normal cold start for a 603.

I'm confused about those numbers. my '87 300sdl is a 603 I assumed? or is the 350 the 603 and the 300 the 602??
anyway, I poured 25% of vegetable oil in the tank when it got warm outside. I thought that wouldn't be a problem... but basically the car has done the stumbling right after the first cold morning of running that 25/75 mix. Even after running normal diesel for 1000's of miles.
this can be coincidence of course. I suspect a lousy spraypattern from the injectors that gets better when they are hot. or that doesn't matter too much when hotter or so. thing is, it ran perfect when I changed injection pump and did a purge, until my rather dumb idea of mixing some oil into the fuel.
planning to do another purge and running it with b100 for a while to see if that clears things up.
the injectors have probably never been changed in the 300k+ miles of the car, that can be the stutter too I presume?
the car has excellent compression, didn't test it but the oilcap doesn't move when loose and idling