It was about 48F this morning. I got into my car (300D), and turned to the glow position. The GP light did not come on, but I gave it enough time to glow and go off, and I started to crank. I cranked a good 15-20 seconds, nothing. So, I tried again, and cranked it, and after about 20 seconds, it turned over, emitting a GREAT BIG plume of black and gray smoke, making the driveway area a little darker in terms of lighting for those few seconds, in fact, there is a big black soot mark on the concrete on the driveway where I started up. So, I'm guessing my compression, starter, and battery were good enough to start minus glow plugs this morning, and I need new GPs, correct?
-Joe

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'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

Next time it does this, give the glowplug relay a light wack with your fist. See if that makes the light come on. IF...you suspect that only the GP light is busted, then listen closely to the relay... It will make a slight clicking sound (if I had to write the sound as a word, I would write: "dink") as it turns off. the relay will stay energized for quite some time after the light goes out..so you have plenty of time to turn the key, and get out to listen for the "dink" sound.

If it turns out, that a good rap on the relay gets things moving, then you can remove the relay, open up the box, and clean the contacts. With just a smidgeon of luck, that will get things working again.

Hope this helps...

-Larry

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

Check the main glow plug strip style fuse. Its located on the left front fender within its own little plastic box. About $0.80 last time I checked.

__________________
84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

What if I hear the "dink" and it stll exhibits the same problems?
-Joe

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

Hey,
I had the same problem and it was definitely the glow plugs. They can be tested with an ohm meter.

Do a search, there are a lot of good threads on this topic out there.
Here's one of them:

http://www.peachparts.com/shopforum/showthread.php?t=113340&page=2&pp=15&highlight=glow+plugs

My Haynes repair manual also shows how to test them.

Danny

__________________
1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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If you hear the "dink" and it still exhibits the same problem, then I would do as Danny suggested, and test the glowplugs.

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

I believe that when two or more glow plugs no longer working, the glow light will not come on.

Pull the glow plug wire harness from the relay and connect one lead - or + doesn't matter, of your digital multi-meter to the any one of the six glow wires (they are numbered) the other lead to a good ground, switch your meter to Ohms, you should see a number show up like these .01 .02 .03 .04 .05 .06 .07 .08 .09 1.0 I tested all six of mine and all were around .05, one was .03 but all work. If you have no numbers come up, and the meter is reading zero, or infinity, you have a dead glow plug!

Another clue that the glowplugs are bad is if it's been starting a bit hard lately and/or running a bit rougher than usual at cold startup. It's not likely several glow plugs packed it in at the exact same time and at that temperature it should start without major cranking even if only 2 or 3 are working. I think the fuse is the likely culpret. I had the same sudden no glow plug problem once on my 603 and found it was a hairline crack on the fuse. How it happened I haven't a clue but the repair was about as easy as it gets. Be sure to actually remove the fuse and examine it because mine looked good but fell apart in my hands when I took it out to clean the ends.

__________________
LRG
1987 300D Turbo 175K
2006 Toyota Prius, efficent but no soul
1985 300 TDT(130K miles of trouble free motoring)now sold

I'm thinking the GPs are dead. I do not have access to a multimeter at this moment. But, it has been starting rough and hard while it's cold, requiring me to put a little foot into it when I start it if it's been sitting for a while.
Thanks for the help.
-Joe

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

Joe, it would be unusual for a bunch of glow plugs to just quit simultaneously. I would suspect you have had a bad one for a while and have now lost another. Buy a set of 5 and then replace the ones that fail. I almost always have a spare, new glow plug in the trunk, along with my tools. This job is made infinitely easier with the ratcheting box end wrenches from Sears (I am sure others make them too). Get the fine pitch ones in the sizes you need in a group, you get more wrenches and it costs about the same. The electrical connection fastener is 8 mm, I believe. I forget the size of the wrench needed to remove and replace the glow plug itself but it was in my set of wrenches from Sears.

I would also check the integrity of the electrical connections themselves. I have had these come loose, and in one case, break off, due to the vibration of the engine. Simple check, just try to turn them on the screw they are connected to, it tells you if they are tight and confirms the nut is still on there.

I would also check the fuse as well. Given your miles, this may not be the culprit but it is a simple visual inspection once you unscrew the two fasteners that hold it in place. Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Did the light ever flash for about 45 seconds after starting? If the light did this, then you have one out; and now one more has gone out causing the light to not come on at all. This of course is not for certain, but definitely should not be overlooked. If the light did not previously exhibit this behavior, please dismiss my remarks.

Thanks
David

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_____________________________________________

2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

_____________________________________________

Here's a neat little way to check your glow plugs without all the fancy tools others tell you to use. take a piece of wire about 6 inches should work. Strip both ends. Go to glow plug relay, disconnect both plugs (big plug and smaller plug). Take the wire a touch one end to each of the metal connectors inside the smaller of the two plugs. Simultaneously touch the other end to the metal thread piece which has a nut tightened around it. If you see a spark, that plug is good. Repeat this step until you don't see sparks/hear them from a connection and you have found the non-functioning glow plug. If you look closely you will see a number on the black plastic plug, and that corresponds to the gp number. I had the same problem over the last 2 weeks and finally found two of my plugs were out. Good luck.


Knight Rider521

______________________
1985 300sd 315k
1986 300sdl 285k

That will only tell you if the resistance is high or low. Sometimes bad plugs will have a resistance of 10 - 80 ohms. You'll still get a spark because it will conduct current. Just not as big as it could be.

Incidently. Sometimes mine work. And sometimes not. I'll take the relay apart at work if I have time. I'll replace those 100 uF 16 volt capacitors while I'm at it.

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

If you do not own a meter for a quick test just take a 12 volt bulb hook up two wires to it. Or a standard 12v test light.Put one wire to the positive terminal of battery the other end to the glow plug in each individual socket connection. If the bulb does not light on one or more connection you have an open glow plug (s) and this is the most common failure.

Well, I replaced the GPs, and it starts perfectly now. I also did a diesel purge. The injectors were pretty dirty, the purge was coming back black. It runs smoother now, and there's no smoke now.
-Joe

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.