Ok, I have been reading all the forum issues regarding the Diesel engine and idle issues, but I could not resolve my issue.

I bought a 1974 W115 240D that hasn't run in the last 10 years.
I brought it home, started it and went around the block, with no power brake or acceleration. there is some pinging noise.

so I cleaned the injectors, put them together, changed some fuel lines and started the car... after 10-15 seconds it dies... I checked the linkage lengths and reset as per manual, and may be I stuffed it up. what ever I do, it starts first go, and idles very high for few seconds and then dies...

I bled the air, cracked the hard lines and removed air, etc...

can anyone point me in the right direction?

thanks a ton! this is my first Mercedes and I want it to be cool...

Is this a Fuel Injection Pump with the Pneumatic Governor?

On a diesel vehicle that has sat for a long time there is a good chance that crud in the Fuel tank is plugging up the tank screen or the filters.

When you cleaned the Injectors I hope you kept the parts of each Injector Nozzle together as they are a mated assembly.

Also if you assemble one piece inside of the Injectors wrong it breaks off part of the Injector Nozzle.

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84 300D, 82 Volvo 244Gl Diesel

Hi Diesel911,

Not sure what injection pump it has.

It went around the block before I cleaned the injectors and changed the diesel lines.

I kept all the injector parts separate and made sure they went with the correct injector.

May be its the tank screen... I will check the filters tomorrow...

Anything else I should be looking at? do you have the throttle linkages specs?

Thanks a lot.

Adjusting the linkage: FSM job 30-300

The engine dying right after starting sounds like you are losing prime.
Old rubber fuel hoses can get dried out and allow air ingress.
Parker 5/16 Super-Flex FL Series 397 hose is an excellent barrier fuel hose (compatible with biodiesel) that I use on my MB diesels.
(Available at your local Parker hose supply or from m*******source.com)

The primer pump before the secondary fuel canister may have a bad diaphragm.


PM me if you need one, I have three on hand.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Probably something to do with fuel. Yet it could be as soon as the vacuum gets established it pulls the injection shut off. Any chance a vacuum line got confused in working on it?


It only takes a minute to remove the vacuum line from the shut off as a test.Far from likely in your situation just something to keep in mind. For example after a long period of not using the back vacuum control on the ignition switch may have called it a day.


Expect things can deteriorate at ten years sitting around.

The OM616.916 in the '74 240D uses a cable from the dash to shut the fuel off - no vacuum signal. Also, this pump is the pneumatically governed type.

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- Greg -
1973 220D, The Prodigal Benz
1974 240D

Was not thinking and I never owned or worked on that model of engine. Sorry.

Barry, I didn't intend to smack down on you! No need for you to be sorry - perhaps I should be. I banged that out right before I left for work and was in a bit of a hurry. Just wanted to help eliminate any confusion about the car's IP.

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- Greg -
1973 220D, The Prodigal Benz
1974 240D

Guys, I did the following today and no improvement...

-Changed all the fuel hoses to new ones.
-Changed the fuel filters
-Converted to fast pencil glow plug (its awesome!)

Previously:
-I cleaned all injectors (kept parts separate for each injector)
-New injector crush washers
-I changed the fuel return lines
-Changed the radiator fluid
-Checked the transmission and engine oil
-Checked power steering oil

Still it starts immediately, idles for few seconds and dies...

If I hold the foot on the throttle, it will start and rev at top of the engine noise, and stays on, but once I take my foot off, it dies...

I think there is a free online site that has the Factory Service Manual. If someone would post that site you could give it a good read on the idle adjustment.

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84 300D, 82 Volvo 244Gl Diesel

I would try some biocide in the tank. It is a likely candidate for bacteria growth in the tank.

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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.

Here it is:
FSM Mercedes-Benz model W114/W115

If you lost prime to the IP after opening the fuel system this post may be of help.

Once you re-establish prime and the IP is no longer air bound, check for air ingress.

Substitute a length of clear vinyl hose for the rubber line that returns fuel to the tank,
it should be long enough to assure that the center of the vinyl hose is above any other point of the fuel system.
Use the hand primer pump to prime the IP fuel supply circuit and remove air from the clear vinyl line.

Any air ingress when the engine is running or shutdown will be evident as an air bubbles appearing in the high point of the clear vinyl hose.
Let us know what this test reveals.

On a tight fuel system there will be no air leaks.
The engine will hesitate and eventually stall if enough air gets into the IP.


If you have no air ingress, the fuel starvation can be due to bad fuel,
StarTron diesel fuel treatment or a biocide (Biobor) can remediate bad fuel.
A mini fuel tank with fresh fuel as a substitute fuel tank under the hood can help eliminate bad fuel from the tank as a cause of your symptoms.

Fuel starvation can also be due to a tired lift pump (needing a rebuild or replacement),
and/or the fuel overflow valve spring needing to be adjusted to increase the fuel pressure feeding the IP.
FSM job 07.1-145

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022

Thanks Team,
I will work on the recommendations and update you all.

Ok... I am royally f**ked now...

I wanted to clean all the fuel filters and so removed all fuel hoses and banjo bolts for the secondary fuel cleaner (large one).

once every thing is cleaned, I noticed that the three banjo bolts have three different hole sizes... I cannot get the description anywhere, which bolt goes in which hole??

Day by day this 240D is getting intriguing :-)

Cheers! and hope you are having a great weekend, while I try to figure out what the f**ks going on??

any help would be greatly appreciated.

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1974 MB W115 240D

How to bleed the secondary fuel filter:
FSM job 07.1-140

Three different sizes of banjo bolts -> three different threads => can only be assembled one way.
Second diagram shows the routing of the fuel lines to the secondary fuel filter.
Mercedes-Benz Teilekatalog (Ersatzteile online)

You may need to replace the crush washers on the banjo fitttings.
Sometimes you can re-use them without getting an air leak.

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78 W116 300SD 'Desert Rose' new as of 01/26/2014
79 W116 300SD 'Stormcloud' RIP 04/11/2022