I was looking at my 1985 300D throttle linkage today and was wondering if my throttle linkage was setup correctly. So here's a series of pictures and questions:

• Throttle Closed is a picture of my throttle linkage at rest. The link to the cruise control has been disconnected which I will explain later.
• Throttle 1 is my pulling the linkage from the accelerator pedal to move that part of the linkage about 1/4 inch. At this point, the linkage makes contact with a tab that engages a cable that runs down the other side of the engine (is this the Bowden cable?).
• Throttle 2 is me continuing to pull the linkage until the roller that moves the link to the IP is engaged. About another 1/2 inch of movement required.
• Throttle Open is the throttle linkage pulled to full open position. The roller that connects to the IP linkage is at the limit of its travel. If the cruise control link is attached, this position cannot be reached; the cruise control stops the roller about 1mm before its stop.

Questions:

1. Is this all adjusted correctly?
2. Should the cable and the IP roller both engage at the same time? How far should the accelerator linkage move before all of this starts happening?
3. Should the cruise control link limit the travel of the IP roller?
4. I have not tried it, but I would guess that full open throttle would yield about 2600-2800 RPM. Is this correct?

Thanks for any advice. I'll make up a DIY when all of this is sorted out.

Attached Thumbnails

       

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Mike Frederick
1986 300SDL, 240K+ miles
1985 300D KaliKar, 270K+ miles

I don't know anything about that linkage, but that engine tops out at 4900-5100 rpm or somewhere in there. So a correctly set full throttle will yield more like those rpms than 2800. At 2800 you're only about halfway into the "power band" of that engine, in my experience. When I'm hustling up an on-ramp trying to get up to speed so I can merge out without getting killed, I routinely run each gear (except 3rd; speed limit) to 3500-4500 before letting it shift to the next. Most acceleration in that range.

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~Michael S.~
Past cars:

1986 300SDL
1987 300SDL
1982 240D
1982 300SD


Current:

1987 300SDL

Hi
Mine works just like yours. Nobody has been able to explain to me why the accelerator has to be pressed down so far before the action is transmitted to the IP. Seems like nothing is happening while the roller moves from one side of the slot to the other. I hope you find out so I can know also. The RPMs will shoot above 4000 at full throttle in neutral - but I would worry about doing that for long.
Joseph

I just went through the same thing thinking it was winter diesel Actually, a vacuum hose to the ALDA was restricting the linkage movement and I wasn't getting full throttle.

I think the more important thing to look at is whether the throttle stop on the IP bottoms out when the linkage on the valve cover maxes out. Also, by moving the linkage from the engine compartment, you won't see any slop between the pedal and where you are moving the linkage. It's best if you have someone operating the pedal while you check the throttle stop. When the pedal is at the floor, obviously, the throttle stop should be maxed out.

Good luck

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1981 300TD "The Green Lantern"
1980 300TD
1983 300D Euro "China Cat"