I have an '82 300D that i'd like to make a little less polluting.

After reading a few threads here, I know that the glow plug system is the reason for my excess smoke and poor idle on a cold startup. I tested this assumption today by letting the plugs heat up until the safety interrupt kicked in (about 20 seconds). Then I engaged the starter and what a difference! Much less smoke and a smoother idle... still not perfect, but better.

So as per one of the threads (and the MB manual procedure 15-710), i tested the resistance of the plugs. Zero on all of them. The manual says they should be less than 1000 ohms, but zero?? Does that sound right? I have no idea how old they are or what brand... but should i just replace them all?

If it is cold and your car is starting OK you might have the ohm meter dial set in the wrong position. On mine I believe you set it at 200ohms. If you have a good plug out of the car check that to see what you get.
http://www.dieselgiant.com/glowplugrepair.htm

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84 300D, 82 Volvo 244Gl Diesel

Just off the top of my head I seem to remember 0.6 to 1.2 being the ideal range, but that might be for a 6.2.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 400,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 22,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.

911, thanks for the link! zero ohms means the plug is internally shorted. 1 ohm or less is what it should be, but not zero. So i'll go back and check my multimeter scale setting and see what i get.

If you are replacing them, Bosch seem to be the most reliable.

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'98 E300 DT
'87 190D 2.5 turbo RIP
'92 S500 Sold
'03 3.2TL-S A-Spec

Also try adjusting the valves and making sure the air filter is still good.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

If you've got a 617 that will start in cold weather with NO functioning glowplugs, we want a complete forensic analysis. That engine has some secret mojo that you could export to every member living in the snow belt.

Do you have any association with Benny Hinn?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Well this car has spent it's whole life in Tucson, so the glow system has never had to work too hard

I think it's probably that the scale on my multimeter was set wrong, but i haven't had a chance to verify it. they obviously do glow, because keeping them on for 20 seconds before hitting the starter does make a big difference. maybe they are just worn and don't glow hot enough, fast enough?

(oh, and the valves have been adjusted and a new air filter was installed a few months ago.)