W123 240d "rodeo" ride

[rydzio]

Hi

I own a euro 240d manual 4 speed. It's the second one I've had. They both seem to be suffering from the same ride quality or power delivery issue. When I drive the car I need to be very gentle about the way I let go or apply the gas pedal. If you simply take your foot off the car will jerk forward and if you apply the accelerator quickly it will jerk forward. I read on other forums that this is normal but I find it hard to believe anyone would buy these cars if they all were like that from the factory.

Please describe your experience with manual w123 diesels. I would be interested in hearing that someone was able to fix his issue.

[koooop]

No such issue with ours, smooth and stinky.

[rydzio]

Just to confirm, yours is also a manual transmission?

[t walgamuth]

I'd look at the accelerator linkage. Sounds like it might be missing some rubber or plastic parts causing odd behavior.

[chasinthesun]

Ck to see if the rearend has alot of play ,you can ck by simply moving the driveshaft back and forth while the car is on the ground.If it rotates some its common wear ,if it rotates 1/2 an inch its severe wear and will need to be serviced or replaced.They call it slop.It would account for the jerkey motions ,if you feather out your driving ,ride the clutch ,you can win out the slack issue ,alot of foot riding the pedal though.Alot gets loose in the suspention also ,the rear suspention gets overlooked more on these cars because of the mileage they perform.Just out of curiosity ,ck to see also if you have a broken shock at its mount,I bought a car with one and the seller thought it had a severe suspention issue that gave the car a bouncey ride ,a $19. shock fixed the problem.

[moon161]

Step/sudden throttle inputs with the manual transmission can excite the drivetrain and suspension in ways that give you a jerky ride or this action can also affect the throttle input and feed the oscillation, so it can go on for several cycles.

One thing to look at is the throttle return damper on the input lever of the injector pump. When you lift off the pedal suddenly, the damper keeeps the throttle input from slamming down to idle.

[rydzio]

Thanks for all the good suggestions so far. The accelerator linkage indeed has a lot of play. There is some on each connection and that cumulates. Also the slop in my rear-end was always suspicious. I can do 1/8 of a turn on the pinion before any wheel starts moving. Throttle return damper is new stabilus brand and mounted as the arrow on the casing indicates. Suspension is all brand new and quality parts used. The car was assembled from bare body using only new stuff.

Seems like I need to get that linkage working accurately because that is easier than a diff swap also finding one in good shape here is like winning the lottery.

[moon161]

If all your rubber and dampers are new, then I'll say, I had to learn early on when I got mine to progressively add/remove throttle, not by a whole lot, but that it matters, as does your reaction wiht the throttle which can pump or kill the oscillation. A neutral as opposed to reactive input will just let it damp down. I think the engine gets to rocking from the drive torque. You might take the hood off and drive around a bit.

Some W123 years use little shocks on the motor at the cradle. You might look into fitting these if the problem continues.

[rydzio]

The idea of retrofitting engine shock absorbers has crossed my mind.

One thing I do not have installed is the t-mount. The one that attaches behind the main small oil pan and on to the crossmember.

[moon161]

Originally Posted by rydzio

The idea of retrofitting engine shock absorbers has crossed my mind.

One thing I do not have installed is the t-mount. The one that attaches behind the main small oil pan and on to the crossmember.

The missing mount is what I would try next.

[rydzio]

The problem is that it does not fit. My guess only but the crossmember seems to have been hit at some point in it's life and is bent forward. I had a separate thread about this. w123 240d engine stop t-mount clerance issue

[rydzio]

The second thing that drives me nuts and it was the same in both 240d's I had is rolling in first gear using engine idle. There is a very unpleasant rubble coming from the back when I do that. Flat road, first gear, engine pulling the car at idle.

Is that normal? Do any of you experience the same?

[bricktron]

not sure about the rumble, but i can vouch for the pulsing behavior that forces me to feather the clutch. maybe i am missing that throttle return damper or have it installed wrong. not the same thing as the rack damper, this is something outside the IP, correct?

[torsionbar]

Originally Posted by rydzio

When I drive the car I need to be very gentle about the way I let go or apply the gas pedal. If you simply take your foot off the car will jerk forward and if you apply the accelerator quickly it will jerk forward.

I've read other threads where that behavior is attributed to a worn out IP. The solution being to have the IP rebuilt.

[koooop]

Originally Posted by rydzio

Just to confirm, yours is also a manual transmission?

1981 240D Four on the floor, Orient Red over Cream, 167,000 miles, original paint and interior.