1972 220D 4 speed manual with later model 240D engine swapped in. Unknown miles.

Motor runs smooth, starts first thing in the cold. Have not checked compression but the motor does not consume much oil. On par with my 82 240D that is much quicker. Burns about 1qt / 1500-2000 miles. Motor has excellent oil pressure. It's basically at about 3.5 bar at hot idle coming off the highway. I'm presuming the motor is in great shape.

The throttle linkage has lots of slop, but when I have someone floor it inside the cabin, all the slack is taken out in the engine bay.

One thing I've noted is that the throttle linkage does not reach the full throttle stop on the injection pump. Even if I disconnect all the links and move just the injection pump arm, it does not reach the full stop. Also the injection pump won't let me manually shut the motor off.

Whats been done:

- New fuel lines (no air leaks)

- New fuel filters

- Tank removed and power washed out, screen removed and cleaned

- Injectors replaced with known good units from another 240D

- New air filter

- valves checked and all within spec, motor oil and filter changed( not that that part would matter)

Symptoms:

Absolutely glacial acceleration in comparison to my 82 240D AUTOMATIC. I would assume the w123 with automatic trans is a heavier car and therefore slower. That car has about 165k miles on it.

Car struggles to climb hills in 3rd gear and will lose speed on the highway in 4th cruising around 65/70 at the slightest incline.

Checked brakes and none are dragging. I'm stumped as to what could make this car so slow. I thought the 4 speed would make it a touch peppier than the auto w123. It is noticeably slower.

240d are slow. Incline should be fine but, is the tank screen replaced as well?

I'd be looking to fix all the slop in the throttle linkage and find out why the IP lever won't hit the full travel stop. If you're not getting full travel when you push the lever manually and you also have a bunch of slop in the pedal linkage, you're probably getting even less throttle from the pedal. Lack of full travel = lack of full power. On an engine that had ~65HP when new, you need all the power you can get.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

The 220D is less powerfull Engine then the later models.

When I got the Car on my Year and model acceleration was extremely bad but once speed was built up it drove normally. When you slowed down to a stop the acceleration issue was back.
It turned out the throttle linkages were extremely sloppy and the throttle lever was not getting moved far enough.
In the Mercedes Service Manual there is specific lengths for the linkage rods and is a few parts back to the acclerator pedal that can wear out.

More recently I was having inconsistence acceleration and the linkage on the fire wall was in bad shape. Replacing that fixed it.

I thought your year and model had a Fuel Injection Pump with Butterfly Valve that controls venturi vacuum in the intake Manifold and a Fuel Injection Pump with a Pneumatic Governor that has a Diaphragm inside.

If your Diaphragm has a vacuum leak you would get smoke because that causes more fuel to be injected.

However, over time the Diaphragms get stiff. I am not sure what symptoms that would cause. Also one side of the diaphragm is exposed to the air and if the vented cap is restricted the Diaphragm cannot work correctly. (Just remove the vented cap and drive and see if there is a change.)
There is threads on replacing the diaphragm.

Restrictions in the tubing to the Venturi.

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84 300D, 82 Volvo 244Gl Diesel

You already found and ignored the problem : the IP isn't reaching full throttle, this is a very serious issue and why I was able to buy my cherry '82 240D for $1,000 in the middle of the Diesel Mercedes craze some years back ~ it barley went 60 MPH on the flat freeway and couldn't go up any hills except in second gear (automatic) with the throttle pinned .

First, disconnect the _vertical_ throttle rod at the IP and figure out if the IP has some binding issue or not, then go through the various pivots and firewall bell cranks etc. and clean and lubricate each one, a little bit of slop anywhere in the throttle linkage results in lack of power and lower top speeds .

Yours sounds like totally screwed up linkages .

A 240D isn't fast but it shouldn't be sluggish either .

It should drive sprightly .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Okay so heres the thing. I have had someone sit in the car and press the pedal to the floor and it is "floored" in the engine bay. So it's not like someone is flooring it but its only at half throttle or something.

Secondly I have a feeling some PO or mechanic could have messed with the full stop on the IP pump. I say this because when I disconnect ALL the linkage to it and simply move it by hand, it does not go all the way to the stop.

So what I'm saying is that while I realize the linkage being sloppy isn't helping anything, I do not believe it is hindering the car from reaching full throttle. Either something is messed up in the IP itself or someone simply turned the full throttle stop in too far ? I'll take a photo or video and post what I'm talking about for clarity.

Got it any why I said # 1 : disconnect the vertical linkage rod and then see if the TP goes to full throttle stop or not .

Then, figure it out from there .

-Nate

Sorry I did not notice the " later model 240D engine swapped in. Unknown miles"

Do you have an MW type Fuel Injection Pump or a M Type? The Governor is different on the MW compared to the M type. And Ya I know the on both the throttle lever is still supposed to rest on the stop on both of them.

Note on a 240D but one of our members with an M type Pump changed the manual shutoff lever shaft O-rings and got something wrong. However, I can't remember the symptoms.

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84 300D, 82 Volvo 244Gl Diesel

If there is a linkage to the Shut Off Lever disconnect that and manipulate the lever and see if that changes the position of the Throttle Lever.

Note that the MW fuel injection pump dose not have a seperate shutoof lever.

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84 300D, 82 Volvo 244Gl Diesel

To answer your initial question, horsepower.


Dan

Are you saying he should get some Horses and hitch them to the Car?

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84 300D, 82 Volvo 244Gl Diesel

Couldn't hurt.


Dan

I might check out the possibility of something else causing the slowness as well. Things that should really be checked out on any new or recent purchase of an old Mercedes diesel.

All too many of these cars have not seen engine attention for almost decades now. They do need a version of a tune up periodically as does any engine. Basically this usually takes time rather than money to do. Except for dealing with the injectors perhaps.

Is the arm on the injection pump moving as far as another injection pump of a similar type.? Is it possible that someone backed off the stop. Thinking they might get a little more fuel at one time?

I assume the function of the stop is to prevent too much stress being applied to the injection pumps internals. Possibly something is bent now inside the pump? Especially as it will not manually shut off. Yet apparently it will still shut down when vacuum activated. So I might leave that for now.

If one assumes the stop was never adjusted. Then a good used pump may be in order. As a percentage of sweep of the arm not very much is missing. So there may be some other issues as well. Usually I never measured them but it seems to me that the lack of lever movement with linkage problems was greater on average than what you have shown.

Many simple tests for a low powered vehicle. Ever take a moderate drive and check the wheel temperatures? I find a lot of dragging calipers sometimes rather than just one getting really hot. Fuel is flowing from the relief valve on the injection pump? If so close the line off and see if there is a real difference. If it is not flowing you are low on fuel pressure is another possibility. Maybe with age you have a really stretched out timing chain. Easy to check. When this is present the cam timing is off and the injection pump is retarded.

I would not expect as much power loss as you are experiencing.. Allow it has been more than a few years since I dealt with linkage problems and the lack of the injector pump arms throw. On 240ds. Your oil consumption is fairly typical for many still decently running 240d engines. The quick startups are also a good sign.

These engines just do not have the power reserves to allow for problems and issues to exist without an obvious penalty. What I am suggesting is not a total waste of time. You in essence are just working backwards to what seems to be an obvious possibility.. What you find could be interesting. You may or may not find something. You might find several things. I might start by seeing what the valve clearances are. This can indicate how much neglect has existed. For example if they are all far too tight. The engine can lose compression as it comes up to temperature. The simple tests involving the relief valves output can clear or condem several things as well.

Okay,

photo for reference. Here is how far from the stop the lever on the IP pump is, regardless of throttle linkage being connected or not.

Would this suggest something within the pump is messed up?

The vertical rod appears to be connected in this photo.....

Be careful here before making any changes, disconnect that vertical rod at the bottom and if the gap is still there then yes, you have a problem, it *might* be as simple as the shut off valve is incorrectly connected inside the injection pump .

To re connect that vertical linkage rod, use a long flat screwdriver and gently apply pressure whilst moving the pivot .

Remember to clean _all_ the rust and crud out of the pivot cup and lubricate it before re assembly .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better