for the love of all that's good and holy, change the glow plugs first!
I had this happen to me about 2 years ago, and I tested with an ohm meter the GP's and they all tested right at 1 ohm, so I investigated additional issues.
pulled cover, and adjusted valves. no start
pulled all injectors and cleaned out the pc's and bled the fuel system... no start
verified the timing of the motor. no start.
tweaked and tinkered many many issues. no start.
gave up and started driving my wagon, then my other SD, then a vw... a 6.2 chebby... all the while trying other things, second guessing myself with valve adjusts, compression tests, etc, etc, etc...
still no start.
tonight, in despiration, (check my other thread... kinda got stranded on the side of the road...) I pulled all the glow plugs *3 were champions... all 5 plugs were dead. no gp's at all...
while bleading the injector lines, gee guess what?
it started just fine...
man I missed driving my 82...SOOOOOO much faster and more powerful than the 83...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Now that they are out of the Engine do the bad Glow Plugs still Ohm out OK?
Also was your Glow Plug Light acting Normal?

I had Champion Glow Plugs (slightly shorter than the Mercedes ones other wise threaded and wired the same) in my Volvo for 10 years before I had even 1 failure. So at least on that application the Champions have held up well.

I do not know if it is suitable for Mercedes Glow Plugs
Over the weekend I saw that some one was selling a factory made Glow Plug Tester. The problem is it was around $75+about $10 shipping.
It is not cold enough here and I do not have a big enough fleet of Diesels to justify buying one.
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=120524640267&viewitem=&sspagename=STRK%3AMEWAX%3AIT

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84 300D, 82 Volvo 244Gl Diesel

nope, in my hands, they all check open... i'm sure that sitting undisturbed for 2 years caused them to fail... yeah, that's gotta be it...

While the eBay Glow Plug Analyzer on is sold by El Paso Tool. Baum Tool has what appears to be the same Analyzer listed in the Mercedes Tool Section a M500 and claims it is for all Diesels.

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84 300D, 82 Volvo 244Gl Diesel

Nooo doubt at all... those nasty phantom electron gremlins just slowly nibbled away finally opening up the circuit on the GP's.

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Couldn't you just use a regular ammeter like in an instrument panel setup and just watch the amperage as the GP glowed?

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Strelnik
Invest in America: Buy a Congressman!

1950 170SD
1951 Citroen 11BN
1953 Citroen 11BNF limo
1953 220a project
1959 180D
1960 190D
1960 Borgward Isabella TS 2dr
1983 240D daily driver
1983 380SL
1990 350SDL daily driver alt
3 x Citroen DS21M, down from 5
3 x Citroen 2CV, down from 6

Times like this is when I just pull the injectors and physically watch them to see if they glow. People call me crazy, but WTF do I know?

I don't know if there is an ammeter for in dash use that's able to handle 80 amps...
but anything amp wise would at least show they are functioning...
I got to checking it, when I noticed the lights didn't dim... measured the volts and they only dropped from 12.6 to 12.4 ... not much load.

My glow plug analyzer consists of a short jumper wire with alligator clips on both ends. I connect one clip to the end of the glow plug and the other end to the positive battery terminal. Then carefully hold the outer casing of the glow plug onto the negative battery terminal. If it starts to smoke and the tip glows red, it's good. If it doesn't glow, then it gets replaced. If it's a good one, I then carefully place it in a spot to cool down; they get very hot, very quick and hold their heat for a while...

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1987 300SDL
2005 Ford Excursion 6.0L Powerstroke, 6" suspension lift

I had the same problem recently, resistance test at the gp relay made them all look ok but probing the glow plug end and the adjacent engine block rooted out the bad one.

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Haven't researched it but... maybe an inductive ammeter?

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Codifex
1981 240D ChinaBlue (Got her running with a donor engine.)
1983 300DTurbo w/sunroof.
1984 300TD manual sunroof. (Electrical Gremlins)

I can tell right away in my car if the GP's are malfunctioning as I have a voltmeter gauge, it'd be pretty obvious if it stayed around 12V while "glowing" that nothing was going on....as normally it drops to about 10.5-11V under the load of the plugs.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I just bought a cheap $20 meter which has DC clamp- on setting good to 400A DC. Piece of cake to test for dead glows. Also good for finding DC shorts. Cheers Dan

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It's always something simple
91 300D 603.960 (from japan) 194K
92 Toyota Diesel Landcruiser HDJ81-t 116K
02 Golf TDI new head courtesy of PO
87 300D
97 BMW 525 TDS Wagon 5spd
bunch of Onan and other diesel generators