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· Registered
4 Posts
Discussion Starter · #1 ·
Hi Forum,

First post here! :grin

I have a great grand old lady named Felicia aka a 200D automatic from 1967.

- Shakes violently when in D and R.
- No problems when driving.
- No problems when in P or N.

Work already done:
- Changed motor/engine mounts (both very bad)
- Changed the flex disc (very bad/worn/torn)
- Changed the gearbox mount (very bad/collapsed)

Did any of these changes fix the problem?
- No :frown

- How do I adjust the idle speed when in D?

The idle cable is missing, so I cannot control the idle speed from the cabin, but if I leave the car in D or R, put a foot to the brake, and manually adjust the idle, the shaking/vibrating is significantly less!

Any help/suggestions/comments are greatly appreciated!



· Registered
519 Posts
I would suggest replacing the idle control cable to get it working. Those old diesels vary a lot in idle speed from cold to hot, so the idle control is real handy. When the engine is cold, it will do a lot of shaking because it is idling too slow. As it warms up, the idle speed increases and the engine runs smoother. If you set the venture idle up so it runs smooth when cold, the engine will have a pretty high idle speed at normal operating temperatures.

· Registered
4 Posts
Discussion Starter · #5 ·
Idle speed adjusted

Hi guys,

Yesterday I played around with the idle screw, and adjusted the idle speed.
It now shakes significantly less - yeah - but it also runs with high RPMs.

I have just bought a new idle control cable, so hopefully that will help as well.

· Cruise Control
'87 300TD Myna 7mm pump and HX30 /'89 Vanagon TDI 12mm pump and GT2052
52,336 Posts
Is there a good online source for the procedures used to set the idle speed and linkage settings on an OM621? I have the paper manual for the early 615 engines, but those use a slightly different linkage arrangement.

· Registered
519 Posts
The adjustments for the early OM615 should be the same as an OM621. Adjustment is pretty simple. From my old Chilton's manual, to adjust the idle speed:

1. Make sure the idle control cable has slack.
2. With engine at normal operating temperature (warmed up), adjust idle speed with the screw at the venturi to 700-800 rpm. This is with the transmission in neutral for a manual or drive for an automatic.

To adjust the idle control cable:

1. Adjust the idle speed.
2. Turn the idle control knob to full idle (cable extended).
3. Adjust the idle control cable at the valve cover relay lever so there is a very slight amount of clearance at the cable end where it attaches to the linkage. Basically you don't want it limit the linkage movement to idle.

To adjust the control rods:

1. Remove the link from the injection pump to the relay lever on the valve cover (link #1 ), the link from the relay lever to the venturi (link #2 with the curve), and the link from the venturi to the relay lever on the side of the engine block (link #3 ).
2. Measure the length from ball center to ball center and adjust the links: Link #1 = 8.1", Link #2 = 12.1", and Link #3 = 9.8".
3. Reinstall all links except for where link #1 attaches to the ball on the valve cover relay lever.
4. Push link #1 all the way down until it stops. This position is the idle stop which reduces idle variations, or "hunting". If it takes more than .04" of lift after it hits the stop to reattach the link, then adjust the link until it takes approximately .04" of lift to reattach.

When the engine is cold, the idle control cable will need to be turned to increase idle. After the engine warms up, it can be turned back down to full idle. Idle speed will increase the warmer the engine gets. Also, it is best to push the foot feed down before increasing the idle with the cable. It reduces the chance of damaging the idle control cable.

Also, I would adjust the idle control cable last if you are also adjusting the links.
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