I finally put a set of Bosch fast glows in my 240D. I just got the glows only...no relay. I got it restarted and noticed that my idle was now fast, about 1,000-1,200rpm. I checked all the linkages and nothing out of wack. I then looked and the pump arm WAS resting against the idle stop. I ended up re-setting the idle screw down a few turns.
Anyone had this happen to them??? Car seems to run better. I did NOTHING else to the engine but put the new glow plugs in. SURE STARTS BETTER NOW!

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My Truck.. 2007 DODGE, 5.9 Cummins, 6spd stick, 4X4. My car..1977 240D, OTHER WHEELS...1955 VW Oval window bug, European Delivery (Holland) with a 1700cc, 2 barrel, Porsche drum brakes. 1939 WILLYS Pick-up. 1967 Triumph 200cc Tiger Cub. 1976 Honda 550F 4cyl Motor Cycle.

Your senario strikes me as more than a little odd. The easier starts are understandable. Once those glow plugs cycle out all is restored as with your old glow plugs. So what concievably could have kicked the idle up?

The only viariable I can really think of is you hit or bent something on the pump when removing and installing the glow plugs? That is unlikely. Or if it is an oddity with the plug change others should have mentioned it. Might want to check the archives. I really do not expect you will find anything though.

About the only other speculation is the intense new heat of the plugs might have had an effect somehow on the prechamber carbon and soot build up. See if your fuel milage is noticably better as well.

I have been watching for a couple of years now. Still unable to find out why some 240ds get around 30 mpg while a lot are lower to mid twenties. I feel when these cars where new they may have all gotten much more simular milage than they seem to get today. I suspect whatever is causing it is a common but unrecognized fault.