Cruise Control Eccentricity

[Geoffrey Ulrich]

Hello from a New Member, new to owning a Mercedes.
I have a 1999 CLK 200. It looks beautiful, it is a pleasure to drive. Everything
seems to work well (except the boot lock key).

The Cruise Control works perfectly except, if a hill causes a gear change down,
then in rapid succession it changes down through all gears. One is then probably
proceeding at about 40 mph in 1st gear with the rev counter where it should not be. Having got things under some semblance of control the engine seems now to be firing only on three cylinders. Stopping the engine for a while seems to reset it and all works well again.

If the hill is familiar, getting a good speed worked up carries on over the top OK but if speed is compromised by traffic then prepare for irrational behavior!

I don't think it should be like this. I shall be pleased to receive Members helpful comments and suggestions.

 

[Dieselman]

Probably the MAF sensor.

As more air is called for the mixture goes lean so it starts to misfire.

For the boot lock, just lubricate and keep working the key.

 

[como]

Welcome.

 

[Geoffrey Ulrich]

Cruise Control

Hi Dieselman,

Thank you for your response. I perhaps didn't explain very well. When the car moving uphill under Cruise Control needs to change down, it moves through each gear from top to bottom in rapid succession, all done in under under five seconds, which means the car pretty well stops without warning, which if your in the outside lane, is extremely dangerous.

The Cruise Control works perfectly on the level, does everything exactly as described in the Hand Book but due to the above experience I switch the CC off at the sniff of a hill.

Can you tell me what the Limiter is for and how it should be used?

Many thanks

 

[Dieselman]

Hi Geoffrey,
I understood your post. The gearbox changes down because the engine is losing power.

To use the limiter, press the end of the CC stalk in and LIM will illuminate on the dash. Select speed by pushing the stalk up or down for 5mph increments or pulling towards you for 1mph increments. Push away to cancel LIM.

 

[Geoffrey Ulrich]

Hi Dieselman,

Thank you for your correspondence. I understand now about the loss of power. Can you tell me what MAF stands for, I'll get it checked anyway.

What is the difference if any, between Cruise control and Limiter? Sorry to be so dumb.

Regards, Geoffrey.

 

[DSM10000]

Hi Dieselman,

Thank you for your correspondence. I understand now about the loss of power. Can you tell me what MAF stands for, I'll get it checked anyway.

What is the difference if any, between Cruise control and Limiter? Sorry to be so dumb.

Regards, Geoffrey.

MAF = Mass Air Flow meter.

Cruise maintains a selected speed, limiter prevents you exceeding a pre-set speed but lets you drive at any other speed up to the limit set.

 

[Igurisu]

Can you tell me what the Limiter is for and how it should be used?

Hello and welcome to the forum

Looking up the limiter in the handbook would suggest one of its main uses is to reduce the maximum speed of the car when using lower rated tyres, it specifically mentions winter tyres. Quite often winters have a lower speed rating than summers so the limiter can be used to ensure you do not drive fatser than the recomended rating.

 

[Geoffrey Ulrich]

Hi Dieselman,

You was bang-on. MAF sensor changed and the car runs smoother, kick down response
positive and hopefully it will perform uphill as it should.

Hi Igurisu,

Thanks for your comments on Limiter. All makes sense.

 

[Transalpir]

MAF = Mass Air Flow meter.

Cruise maintains a selected speed, limiter prevents you exceeding a pre-set speed but lets you drive at any other speed up to the limit set.

You can exceed this "limited speed in an emergency, to get out of troble where acceleration is the safest option...

When operating the car with the limiter active ...you press the accelerator peddle beyond the point of ressistance, ie "Kick down" this overrides the set limit, allowing:bannana: rapid speed gain when needed!