I have a 1976 300d
The car would crank and run a couple of days ago. My daughter tried to drive it and it would not start. The glow plug light was not on. I checked the timer relay and it was loose. I tried to start the car and it just turns but won’t start
Any ideas

There is a ton of information about checking the glow plugs. This is the first place to start. If your engine has the original type glow plugs especially.


You can identify them by the squiggly large wires running between some of them . If one has burnt out they all are not working. They are wired in series. Like an old fashion string of Christmas tree lights.

Look on the fire wall and see if there is a single metal fuse under a plastic cover. See if it is burned.

If you have the system that has the zig-zag wires if one glow plug burns out it opens the circuit and no electricity is getting conducted through any of the glow plugs the Glow plugs.

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84 300D, 82 Volvo 244Gl Diesel

Repair Links
Fast navigation http://www.peachparts.com/shopforum/diy-links-parts-category/146034-fast-navigation-do-yourself-links.html

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84 300D, 82 Volvo 244Gl Diesel

Thanks! I will check them out

Is it the loop style glow plug? If yes one of the plug is broken.

Yes those are the loop plug type. Or original type to his engine. There are other possibilities than a broken or bad individual plug though. Even if it is the most likely scenario. First of all just to establish if they are the issue. Then the old relay may have timed out with age. The fuse on the firewall may be open. A poor connection in the system. An open or bad plug is high on the list though.

I’m new to this. If there is a fuse where would it be located? Also, how do I test to see if they are getting in power to glow? The relay is working as it turns of the light inside the car but I don’t the plugs are heating.

There will be no fuse. The relay is under the dash. If you have a multimeter, glow the plugs, and measure the voltage at the #5 plug;it should be 10.5v If it's 12v you have a problem with one of the plugs, measure each plug until you find the one that reads 0v and replace.

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Marc-André

W115 1975 300D "Geraldine"
W115 1976 300D parts/tutorial car

the fuse is on the firewall on a pre 1980 OM617 engines.



I would suggest you upgrade it to new type glow pencils.

http://www.peachparts.com/shopforum/diesel-discussion/396192-om617-loop-spiral-pencil.html

If this is a W115 there is no fuse.

__________________
Marc-André

W115 1975 300D "Geraldine"
W115 1976 300D parts/tutorial car

We dont know what the OP car is...... 76 could be both. I have seen 76 w123s here.

My car is a 76 w115
I think the i have a bad one. My car has the large temp sensor in the head. Would converting it to the newer style plugs be difficult. What type of modifications would be needed?

easy:

- A relay (120A) or a modern glow plug relay.
- Wiring (thick ones min 6 AWG /10mm2) and eye terminals m5 (10x) m6 (2x) m8 (3x)
- Wiring for the bypass, eye terminals and spade terminals. (a few needed)
- Wiring for the modern glow plug relay. Don't worry most of them work the same way.
- new type glow plugs
- Fuse (maxi one)
- Timer relay when using only a normal relay.
- M18 x 1.5 Reamer to clean the glow plug holes
- Some anti seize on the glow plug threads.
- Some self tap screws

I used my original relay to use it as a timer.

















I made this diagram by myself: (thermoswitch is the temp sensor).





Temporarily fix since I know the light will stay one till the safety cut out or starter engages. I need to put a timer between it.



If you use a modern glow plug relay you can rewire it on the new one so the light will work correctly. Since the old system uses resistance as glow plug light timer.