240D air manifold something missing??
 

My w114 240D seems to have a problem when accelerating, I put my foot down and it kind of drops before it accelerates.

I have been looking at the manifold area and I think there may be something missing in the red area. I would expect this to rotate but as I don't know enough about these cars I am a little in the dark.

Any help would be appreciated.


http://img816.imageshack.us/img816/391/p1020262.jpg

Kind regards.

or does anyone know where I can get an electronic copy of a w114/115 diesel manual?

I don`t have anything on the W114/115 but this site might have what you are looking for.


http://www.mercedesmanuals.com/Mercedes_Benz_Repair_Manuals_1970_1979_s/557.htm

Charlie

Looks like a good start, thanks.

There should be a bi-metallic spring there which I believe helps with cold idle.

What is the cable with the red cover on it, that is not original.

That looks like the auto transmission throttle cable on both of my w126 cars.

Yes on your car it is the transmission pressure control cable. But the early cars didnt have this, they used solid metal linkage for the control pressure.

I thought that was the return lever for the anti-backrunning valve the intake body has.

I was confused for a moment at the brake booster line until I realized the location being in the UK :D

Here a video of said spring http://www.youtube.com/watch?v=9YQfeUj3eZk

To be honest im not 100% sure what it does exactly.

That video helps, I can now fashion something spring like to replace the missing part.

Thanks.

OK, I have now fixed that but I still have a problem.

When I open up the throttle there is a power drop before it increases.

In neutral, I put my foot down and the revs seem to drop before they go up.

Any ideas???

I've always wondered about that piece, too. Rotating it closes a flap in the intake manifold. From reading a few threads on here some time ago, I believe diametricalbenz is correct, that the flap is designed to close if somehow one managed to start the engine rotating in the reverse direction (where the intake would become exhaust), allowing it to be shut down.

Mine doesn't have a spring like the one in the video, in fact I've never seen any other W115 diesel that had one like that. Though I think it's odd that it would be free to move back & forth.

I wonder about that linkage with the flexible rubber boot in the picture - on my car, and others that I've seen, this is a straight metal rod. Did you observe its action when you move the throttle linkage? If it's flexing....that could cause your problem when you put your foot to the floor.

Otherwise, I'd think a loss of power when you hit the throttle would be caused by a momentary fuel starvation.

Putting the pedal to the metal on my car is very underwhelming....it doesn't speed up much at all until the revs get into the very narrow torque curve and then there's a sudden surge of power. I think that's normal, but I'm not sure...I drove a W123 240D once and the acceleration felt more linear.

Ill take a closer look at the linkage tomorrow, i does look like its flexible in the photo.

I guess its never going to be the most responsive of engines and sadly I don't know anyone who has one which I could listen to or drive to compare against, but it just seems wrong and to be honest I cant trust much on the car.

Yep, its a cable with a bit of slack in.

The history of this car is that its had a petro, to diesel engine swap and I am guessing the guy who done it didnt do a very good job.

The proble is I dont think this would explain the drop in revs when I rev the car.

Any way, ill fix this problem then see if therer is any change.

Regards

Brett