My friends 1980 300D does not fire up.
170K miles. Gas tank cleaned and new tank filter 5 years ago. Battery good. New starter. Glow plugs were pulled out and confirmed to get hot although the glow plug light on the dashboard stays on indefinitely even after the click sound is heard from the driver's side fender area. as per past posts, the filters were cahnged and confirmed to get gas flow from pump with pre-filter off.
So it cranks over fine but that is it.
Will try Benzmac's tip to run comressed air back into tank with gas cap off but until then does anybody have any ideas? Also will have valve gaps adjusted in case that might help. What's up DOC ?
Thanks.

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1979 300D
133K miles
1989 300SE
1995 C280

One thing for sure, your glow plugs have problem. Fix it before you move on to other problems if any. You cannot test the glow plugs by touching them.

David

I totally agree with be549. Check the glow plugs with a voltmeter.

Good luck,

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Hee hee. "You cannot test the glow plugs by touching them" - that's a fact. If you can touch them, they're bad. If they are working properly, if you touch them while they're hot you'll lose some skin from your finger.

- Nathan
'83 240D, 250k miles

UNKL300D,
one thing that poped into my mind is the vacum system. Is the shutoff switch on the pump getting vacum? Is it activating the pump?
Just my 2c worth.
Mark.

Two things. The glow plugs will pull 20Amps a piece. The rack on the fuel pump can be stuck. The side cover on the fuel injection pump can have no dents in it or be overtightned.

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope :)
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Try pumping the hand pump vigorously. My 300SD wouldn't start after I changed the fuel filters and pumping the hand pump got it going. Never had trouble again.

Did the engine fail to start after the filters were changed or was that one of the things that was done because it wouldn't start? If it was running before the filter change but won't start afterward, I have had a similar experience and think I may be able to help you. Until I know, however, it may not be worthwhile to go through it now.

If you are still having trouble, let me know.

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Ted
1979 240D

You have to check glow plug system.

Also, try loosening one high pressure line at any one injector, check for fuel output while cranking the engine.

At the very least, you'll know if you have an electrical, or a fuel system problem.

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Jake

Thanks for the replies. We got a kick out of the finger test chide ! Actually
mosquitoes were used as test subjects
Hee hee.
The fuel filter replacement came after the fact but did not help.
Further tests will be done to determine if it is a fuel or electric (glow plug) problem.
p.s. this same friend of mine recently had
the engine rebuilt to his low milage '94 S350D. $$$ugh. lemon city.

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1979 300D
133K miles
1989 300SE
1995 C280

I also had the same problem with my 1981 200D and they found out my heater relay was defective. I replaced the part and every morning it takes about 3secs to fire up!


1983 300SD
1981 200D
1977 240D
1977 300D
1962 190c

Although the fuel pump did pump fuel, it was replaced anyway and the car started
up and runs better than ever !

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1979 300D
133K miles
1989 300SE
1995 C280