i have a 1980 300D and hav trouble starting it after a couple of years. I heard about an ignitor in some cars. does this car have an ignitor ? if it does where is it located and what effect does it have on starting it?

It has a set of five glow plugs.

If one or more than one glow plug has failed, you'll definitely have trouble starting it.

Have you checked to make sure all 5 glow plugs are working?
Have you adjusted the valves?
Check the timing?
Have you had the injector pop pressure and spray pattern tested?
Is the starter strong?
How are the grounds?
Is the battery in good shape and the right one?

Does your car have a block heater and do you use it?
When its real cold synthetic oil cranks over a lot faster then dino.

If the answer is yes to all the above time for a compression and leak down test.

If in proper tune starting is a non issue.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

in my gas stove, my gas water heater and my gas furnace.

none in my diesel.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I will expose my ignorance...
Would a spark plug in place of a GP work?
For sake of exposing my ignorance let's assume the timing can be set to 'ideal' settings.

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82 300D....went to MB heaven
90 350 SDL....excercising con rods

I do understand the compression ignition...but when they are having a hard time w/ just compression wouldn't a spark help start the burning? Similar in theory to the GPs running after startup but all the time.

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82 300D....went to MB heaven
90 350 SDL....excercising con rods

will ignite diesel. my son filled my 67 jeepster with it and it ran...barely, and smoked like a fiend.

for a diesel the compression ignition works so much better.

besides how you going to provide it? install a distributor, plug wires, a coil, etc.? yikes!

just get your glow plugs working and unless you are low on compression or the valves are leaking you will run fine.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I offer the following just for learning points, to figure out your problem the steps already posted are adequate.

Realize a diesel engine works because it creates so much pressure on the fuel that the fuel explodes. A gas engine fires a spark to ignite fuel.

I think there's two problems with the spark plug. A) a glow plug is meant to warm the engine/combustion chamber to help create more pressure, not cause combustion on it's own. B) You have no way to suppy power to a spark plug.

It ain't gonna work. GP's may run after startup but that's only to add heat to the chamber, not to actually combust fuel itself.

Good luck,
Bill

To add another "no"; glow plugs generate about 900 degrees Centigrade over a rather large surface area in a continuous fashion. A spark plug generates a momentary hot spot over a very small surface area. A glow plug generates enough heat to keep itself clean of carbon deposits, whereas a spark plug does not and will foul in short order.
If I remember my Dad correctly, regarding nomenclature history, "ignitor" referred to the magneto, which was used in early gasoline engines before batterie's were used to supply current to run a breaker point / coil setup, as well as current to run a starter motor.

I think he is talking about the Ignitor electronic ignition unit. No possible way to use one in a diesel (no ignition system), but for a older gas engine with points it is the best $70 you can spend.

__________________
Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section

Glow Plugs do not create more pressure.

In M-B indirect ingnition engines (616, 617, 6022, 623, etc.) fuel is injected into a pre-combustion chamber. Heat from compression raises the air temperature above ignition temperature of the fuel, which begins to burn as soon as it is injected.

Glow Plugs are used to heat this pre-chamber before starting, when the metal is cold and absorbs some of this compression heat. A lot of cranking on a cold engine will eventually make enough heat from compression to raise the pre-chamber to the proper temperature, but the Glow Plugs make it much faster.

Actually you can put the 12 volt GP lead on a spark plug, but you won't get a spark...

Spark plugs need to have 15,000 volts applied across the gap, or they don't spark.

Ignitior is a component on a distributor in a spark equiped car, ie gas powered.

I hate spark plugs.

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1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
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I love the smell of diesel smoke in my hair