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Old 01-28-2008, 12:03 AM
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Join Date: Jan 2008
Posts: 2
HI all from Missouri! 240d start problem

I am looking at a 240d that won't start............I am a farmer and have been around diesel engines.......but not mercedes.........I need some direction........

figure I will start with glow plugs and relay...........where is relay located?

battery is low from them trying to start it.........I will jump it with big cables I use on Farm tractors........where is starter plan on tapping on it........

Anyone that can take a moment and give me some insite I would sure appreciate this is my first maybe Mercedes............

it is I believe either a 78 or 77 model

any help appreciated!
Thanks Scott

Going to look at it like 1030 Monday morning........

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Old 01-28-2008, 12:06 AM
pawoSD's Avatar
Join Date: Oct 2004
Location: Grand Rapids, MI
Posts: 15,315
Relay is on the drivers side fender. Black box with a couple cables going into the top. Most likely you have dead glow plugs. You'll need to replace them or its not going to want to start if its below 65-70F out. Starter is on the passenger side of the engine below the air cleaner housing....don't crank too long or it will fry the starter, fix the glow plugs first. You could also have a fuel issue, clogged filters or tank strainer, or air in the lines etc....
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 90k - mine - (OC-91,200)
'17 Metris(VITO!) - 18k - wifes (OC-25k)
'01 E320 Wagon - 161k - mine (OC-165,000)
'01 E320 - 180k - dad's (OC-182,500)
'07 E350 Wagon - 134k - dad's (OC-139,500)
'01 SL500 - 56k - dad's (OC-59,000)
'16 E400 4matic Sedan - 81k - Brothers (OC-88,000)
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Old 01-28-2008, 12:16 AM
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Join Date: Jan 2008
Posts: 2
well from what I was told it started one day it wouldn't I figure glow plugs are bad too.........can you shoot a little either to these( I know just a bit not much) to start them in emergency?

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Old 01-28-2008, 12:27 AM
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Join Date: Jan 2002
Posts: 18,355
I don't think the relay is in that location on this car. 77 or 78's, if original, have series glowplugs. If one goes out, they all go out. If original, the plugs get their power from a box on the firewall, juice goes thru all the plugs to the ground at the first plug at the front of the engine. You can tell if they are working because the heavy wires that join the plugs will glow red hot and be visible if the sun is not too bright.
Inside the little plastic box on the firewall from which the plugs get their juices is an 80 amp strip fuse. They can get hairline cracks and fail. You can use a small heavy gauge jumper wire between the screws that hold the fuse to get juice and test the plugs. You could also use a jumper wire from the hot terminal on the battery directly to the first plug at the back of the engine.

If plugs are bad, you really want to convert it from a series loop system to a parallel pencil system. Conversions plugs are available. Search the forum for the part number. The conversion plugs are not the same as the later pencil plugs because the threads are larger. To convert, remove the series plugs, remove the ground wire from plug at front of engine. Use wire from the firewall to energize the first plug at the back of the engine and put jumper wires between the remaining plugs. This will improve cold starts immensely.

Only use ether in an extreme emergency with the glowplugs disconnected.

If you can farm, you can fix it.
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
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Old 01-28-2008, 12:30 AM
yellowbenz's Avatar
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Join Date: Jun 2005
Location: Columbia, Missouri
Posts: 643
Don't use ether. Some suggest wd-40. Where in Missouri are you located?

1978 300D
1979 240D
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Old 01-28-2008, 12:52 AM
Biodiesel300TD's Avatar
Join Date: Dec 2004
Location: Albany, OR
Posts: 4,845
The glow plug relay on the early models is under the foot well panels. It is a silver box, and it's it located right near the steering column. It sounds like bad glow plugs to me if it started one day and not the next.
'04 Jetta TDI Wagon
'82 300TD ~ Winnie ~ Sold
'77 300D ~ Sold
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Old 01-28-2008, 08:58 AM
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Join Date: Feb 2007
Location: Lexington, NC or Boone, NC
Posts: 2,272
Little shot of ether shouldn't hurt anything.

If you're nervous about the glow plugs igniting the ether - just turn the switch on and then let the car sit for a full minute before you try to start it.

Then, you are 100% positive the glow plugs have stopped running (If, as we do not suspect, they are working) - after that point, give it a quick, short, and one-time-only shot of ether to see if it'll start. If it does, we know your fuel delivery and things are probably okay.

After that, fix it right

Ether doesn't kill these cars. Irresponsible use of ether kills these cars.

"What could possibly go wrong?"

~Michael S.~ -
1986 M-B 300SDL, retired due to rust and electrical problems. Donated engine to:
1987 M-B 300SDL, odo dead. New project.
1982 M-B 240D, odo stopped at 308,000
1982 M-B 300SD, 175,000
1989 Dodge Ramcharger, 87,000 - 4wd, 318
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Old 01-28-2008, 09:11 AM
vstech's Avatar
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,389
most older tractors use the same type glow plugs, so you should be familliar with them.
if not, bear in mind that they are series IF they still have the large bendy metal bracket looking wires between each glow plug. simple check is to put volt meter on engine block and last glow plug and check for any voltage. if you have around 3 volts, you are good. if you have 0 you are bad. the fuse on the firewall on that old a car is 50A, not 80A... have fun!

John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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