idle again!!

[alexbartman]

Still got my idling/automatic creep probs...I need to ask again....
My car idles at 600rpm in Drive with my foot on the brake- this doesnt seem to be high enough to creep the car forward in traffic and as a result the slow trawl through everyday traffi cis quite jerky. If I put the car in Park - the idle goes to c.750rpm - with seems a lot smoother......is theis to be expected or should the idel be adjusted up to allow a stronger creep - which is really handy on hills, in traffic and when parking....

 

[grober]

The idle speed rises in park or neutral because there is slightly less drive load on the engine via the torque converter and is to be expected. There should be a fixed design idle speed for the car although this can be affected by temperature factors and additional engine loads such as air conditioning. There should also be feedback sensor inputs to the engine ECU to compensate for these extra loads but the sophistication of this depends on the age and model of the car. You could try switching on and off some of the extra loads to see if this affects things.
PS always best to post your model and age of car details with your question.

 

[alexbartman]

forgot to mention... I have a 2001 CLK (W208) 320 vert...not sure if that will generate soem more answers!!?

 

[Dieselman]

The idle should be fixed at a set value. If more load is applied the idle bypass should allow more air intot eh engine to bring the idle back to spec. It sounds like that isn't working properly.