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-   -   Possibly not getting full throttle? (http://www.peachparts.com/shopforum/diesel-discussion/68871-possibly-not-getting-full-throttle.html)

The Warden 06-29-2003 11:11 PM

Possibly not getting full throttle?
 
Hello! I was just out at the car trying to see what I could do to keep the air cleaner from rattling all over the place (need to replace the rubber mounts, but i want to go to the cleaner that mounts right by the turbo like what Alex has, so I'm holding off), and being weird, I went to play with the throttle linkage around. I found something interesting.

By moving the lever that comes up from the throttle pedal (didn't have a 2nd person to actually depress the pedal), it looked like the linkage up on top of the valve cover was moving as far as it should. However, when moving the linkage at the injector pump, it semed to move a little bit more. From the STOP lever, there's a bar that runs down to the pump, and connects to a couple of other things down there. One thing moved front-to-back and looks like it's supposed to be coming into contact with a set screw at WOT. When moving the bar that comes from the pedal, there's still roughly 1/8" of space in between the two, but if I move the STOP lever, I can get it to come all the way into contact with the screw. The rest of the linkage seems to move the same amount when I do this, and I don't know where this extra play's coming from (internal to the injector pump, maybe?).

Is the lever or whatnot supposed to come in contact with that set screw at WOT? If so, how should I go about adjusting the linkage so it does?

Thoughts appreciated. Thanks in advance! I wonder if this could also explain why my idle seems a bit low...?

coachgeo 06-29-2003 11:45 PM

Your doing WAYYYYYYY better than I :D

When I first discovered this situation on my rig I had 3/4" from end of lever to the throttle stop screw.

Take 2x4 or.. heck you cars window squeegee and find away to prop it in the the car holding the pedal to the medal, and then look at you last link and the throttle stop screw. Still 1/8" ?

I would GUESS that you have some wear and tear of the little ball joints etc. therefor that tiny play creates motion inside each link prior to moving the next link and so on till it actualy moves the IP's throttle linkage. That tiny play at each link adds up.

I had to shorten some of my links to take up this play. (ALOT) but remember mine was excessive and bastardized. I started at the furthest away link (pedal's) and worked forward till my actual foot pedal's range of movement on the levers prior to the IP was maximized. I then adjusted levers right at the last link before the IP to make sure that my new foot pedal's range of motion was used effectively to move the IP's linkage thru its proper range of motion.

My linkage is made of a mix match of MB but it is void of all the ancillary linkages that the car has, yet I think conceptually the concept would still apply though. Those more in the know will either Kill me (understandably) for the missinformation I just accidently spread or add to it with far better detail.

thatttt being said...... Is 1/8th of an inch worth worrying about???? btw... Thats what Ive ended up with too.

JimSmith 06-30-2003 12:42 AM

The Warden,

On my daughter's 1982 240D I noticed once when she was home from college for a weekend a few years ago that the car was really pretty dead. I popped the hood and began checking things out and I found the assembly kind of suspended from the valve cover has a joint where the connection from the pedal is already turned into rotational motion through some links that was very loose. It has two prongs that used to fit into a rubber disc bonded to the part that is "with" the linkage suspended from the valve cover. The rubber was gone and the clearance around the prongs was about twice the thickness of the prongs. This used up about half the pedal travel before the linkage suspended from the valve cover began to move the connection to the injection pump.

I have not been able to find a new part, so I repaired the old part using popsicle sticks and electrical tape to "thicken" the prongs so they have a tight fit as they pass through the now all metal connection plate. The difference is amazing, like it went from two cylinders to four. Granted it is not really pretty, but it works and only needs to be replaced every year or so.

There is another joint on the firewall, a kind of ball and socket thing that also fails and leads to poor throttle response. It is at the end of the rod that connects to the linkage suspended from the valve cover. When it fails, it allows lateral motion that uses up a bit of the pedal travel before it twists the rod. This part is readily available and I have replaced it on my Father-in-law's 1980 240D. Good luck, Jim

coachgeo 06-30-2003 12:50 AM

Quote:

Originally posted by JimSmith
The Warden,

On my daughter's 1982 240D I noticed once when she was home from college for a weekend a few years ago that the car was really pretty dead. I popped the hood and began checking things out and I found the assembly kind of suspended from the valve cover has a joint where the connection from the pedal is already turned into rotational motion through some links that was very loose. It has two prongs that used to fit into a rubber disc bonded to the part that is "with" the linkage suspended from the valve cover. The rubber was gone and the clearance around the prongs was about twice the thickness of the prongs. This used up about half the pedal travel before the linkage suspended from the valve cover began to move the connection to the injection pump.

I have not been able to find a new part, ...

If you get me a picture of this I will check the car I am going to pull a few parts from and see if it has the same one on it. I was reading some time back about this issue of the bad rubber and when I was last at the junker they caught my eye and suprised me that for such a poorly maintained car those rubberized links looked in good shape.

JimSmith 06-30-2003 03:18 PM

The Warden,

My daughter has the 240D in San Diego, and I am in Connecticut. So, I cannot photograph the parts or I would.

They are pretty easy to trace. There is a mechanism on the firewall that the throttle pedal is connected to, that turns the up and down linear motion of the pedal linkage to a rotational motion to deliver torque via a fore and aft oriented rod that goes from the firewall to the cluster of brackets and linkages suspended from the valve cover. At the end of this rod is the rubber/metal bonded part in question, which turns the rotational motion back into a linear up and down motion to move the throttle controls on the injection pump. There is also a connection to the cruise control and, on a 240D, the idle speed adjustment.

Good luck, Jim

The Warden 06-30-2003 04:06 PM

Well, I got my trusty girlfriend to help by pushing the pedal down. It looked like everything was okay, except for the point on the injector pump not contacting the stop. I didn't see any excessive play; I think that it just got out of spec by a little bit.

So, I adusted the linkage at the rod going down to the injector pump...all I can say is

OH...MY...GOD!!!

It's like a whole new car. Before, I had to floor it to get out of its own way; now I can go about that fast at half throttle, and full throttle is something else entirely.

Man, I thought the OM617's were supposed to be slow!! :) I'm still in shock...I had thought that the car was supposed to drive like this...I guess I was wrong. :)

Thank you all!!

coachgeo 06-30-2003 04:24 PM

Quote:

Originally posted by JimSmith
The Warden,

My daughter has the 240D in San Diego, and I am in Connecticut. So, I cannot photograph the parts or I would.

Good luck, Jim

Yeah Jim I know where it is located. What I dont know if this car with a 617 turbo uses the same link. In concept I know they function the same but I dont know if they are the same in reality.

Sorry I dont remember what car it is that is out there. I'll look on whats left of the trunk to see.

coachgeo 06-30-2003 04:31 PM

Quote:

Originally posted by The Warden
Well, I got my trusty girlfriend to help ..
Does she have a twin? :D

Quote:

So, I adusted the linkage at the rod going down to the injector pump...all I can say is

OH...MY...GOD!!!

It's like a whole new car. ..
Yeah that's what it was like for me on my first adjustment when I got a little more of the throttle. My last adjustment still gained me a tiny amount.

What supprised me is my booste went down. I use to have to pedal to the medal my 5.5 ton thing to go 50ish mph..... and the booste needle would bounce around 0.55 bar of boost. Now it's solid boost at 0.45bar doing 55mph with plenty throttle left.


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