Idle on a 6.9

[Michel]

I just decided to drive the 690SEL home tonight from work (it is usually garaged in the office complex) and noticed that the idle in neutral was over 1000 rpms.
Is that normal (the car was relatively warm)?

What should the idle be on cold and on warm in Neutral and in Drive?

 

[Styria]

Hi Michel, do you remember that I mentioned to you some time ago that your thermostat was ioperative - the engine is NOT getting hot enough, the motor thinks it's too cold and the system supplies more fuel because it thinks it is too cold - which it is.

If it's still idling too fast after installing the correct 87 degree thermostat, you may need to look at the mixture, a leak in the vacuum system allowing excessive air, or to check the auxiliary cold start valve. Regards Styria

 

[Michel]

Hi Michel, do you remember that I mentioned to you some time ago that your thermostat was ioperative - the engine is NOT getting hot enough, the motor thinks it's too cold and the system supplies more fuel because it thinks it is too cold - which it is.

If it's still idling too fast after installing the correct 87 degree thermostat, you may need to look at the mixture, a leak in the vacuum system allowing excessive air, or to check the auxiliary cold start valve. Regards Styria

Good point Godfather....

 

[WGB]

Another cause for a high idle is a depressurised A/C system with the idle increasing circuit operating but the compressor not compressing.

My car used to idle at 1100 revs before I finally sealed the system.

I have a 75 degree thermostat in my car Styria and have no idle problems - even in cold weather.

Bill

 

[Styria]

That's surprising, Bill. I still wouldn't be happy to use a 75 degree thermostat. In my opinion, Michel's does not work at all. Regards Styria