When I bought my 83 300CD two years agao, I replaced all 5 glowplugs with new Bosh glowplugs. But, I seem to have to replace some here or there, about every 6-9 months?

Is this normal? How long should these things last anyway?

Yesterday, I checked with my ohmmeter, and found my rediculously terrible starting issue was because glow plug cyl#2 needed to be replaced, and this morning she fired right up like a freaking gasser? Is it normal, that replacing a single glow plug would make that big of a difference? It make it seem like the car is running on that one cylindar alone, or they are wired like christmass lights?

Mark

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1983 300CD 245K
Running WVO blends

The relay cuts the power early if there is too little current flowing. Losing one plug shouldn't be enough to trigger this except perhaps if it's #1.

As for burning them out, see how long it takes them to shut off when you start the engine in the cold. They could be running too long.

Did you ream the GP holes to get rid of the carbon? The carbon can become the point of a short.

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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

I tested all my plugs about a year ago and found #2 to be bad. It went from taking 15 seconds of cranking two or three times to starting right up after a couple revolutions so I would say yes, one bad plug makes a big difference.

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1982 300TD 279K.
1984 190D 5sp 265K

Yes, one plug makes a big difference. And if you don't ream out the plug holes, the carbon contacting the new plug will cause a temperature difference on the plug where it will burn out quickly.

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'83 240D with 617.952 and 2.88
'01 VW Beetle TDI
'05 Jeep Liberty CRD
'89 Toyota 4x4, needs 2L-T
'78 280Z with L28ET - 12.86@110
Oil Burner Kartel #35

http://i16.photobucket.com/albums/b1...oD/bioclip.jpg

How can I tell if the glowplugs are running after the car has started?
Do I go under the hood and try to get my multimeter in there and touch one of them on the bouncing engine?

Maybe I should just get a "new" controller/timer I replaced my original one with a used one off ebay, but the last I checked they were like $180 or something.

Or just a simple starter solenoid relay from some old car and a push button to control it with. Id hook all 5 up to it in paralell, and use a button that you have to hold down with your finger for the glowplugs to be on, so you couldn't leave them on, and burn them out. If it starts stalling after startup, just put your finger back on the button. I think I could count to 10 in cold weather and 5 in warm weather with my own brain...one onthousand two onethousand, etc, and err on the short side so as not to burn out my precious plugs.

Mark

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1983 300CD 245K
Running WVO blends

Just a point to ponder:

The SD had #5 out for several months. The only way I would know is if I started it with no pedal and let it idle. Then the thumping of four cylinders would be unmistakeable for about 15 seconds. If I used a bit of pedal, and the revs came up to 1000 rpm.......#5 would quickly come on line within a second or so..........not even noticeable.

The time to start never varied. It started on 4 in one second.........every time.

Goes to show..........compression rules.......!

Not if, but how long. Turn on your dome lamp when you start the engine. It will get brighter when the plugs shut off.

Get a small alligator clip and clip the lead on the multimeter to the tip of the #1 glow plug. The ground lead goes to battery negative.

Get another person to start the vehicle.

The moment the key goes to the "start" position, voltage to the plug should disappear..........and remain zero while the engine is running.

There's no intentional afterglow on the OM617?

Correct.

Well that rules out plugs being my problem.

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1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42