Cruise Contol ???

[SEM]

Cautionary tale
I used my limiter on a 40mph road with lots of speed cameras. I set it at 35 and took the car a little over… the srs kicked in then packed up causing the car to throw a fit and shut down. I pulled over… turned off the ignition and restarted, everything worked fine but left the srs light on, which I got fixed. I’m frightened to use the limiter now in case it does it again at higher speeds

 

[Shude]

Cautionary tale
I used my limiter on a 40mph road with lots of speed cameras. I set it at 35 and took the car a little over… the srs kicked in then packed up causing the car to throw a fit and shut down. I pulled over… turned off the ignition and restarted, everything worked fine but left the srs light on, which I got fixed. I’m frightened to use the limiter now in case it does it again at higher speeds

You can get away with up to about 10mph over the limiter but anything more than that and it slams it into a much lower gear and uses the engine to slow the car down, which is not only bad for the gearbox and engine but also for the heartrate of the driver behind you!

 

[Rose Chap]

This forum, whilst not only saving me from the drugery of actually having to do some work on a Friday afternoon, has now taught me I can increase and decrease my speed in 1mph increments!!! Thanks to you all!

What next? Will the forum bring coffee to my desk?

 

[mickl]

Went over to Nottingham last night (A50, M1) Using cruise control it would not cruise over 80. If I setcruise at 80 it would be be ok for a few seconds and then just cut off and start slowing.

Holding the cruise control lever up it would accelerate past 80 and the cut off again. If I then pushed the lever back up it would not accelerate.

Any ideas??

Thanks

*EDIT*

The fastest it would cruise at was about 76

I got the same thing when I put 18"s on mine. It cleared after going back to 17"s. It wouldn't hold anything about 70-73mph. Never found out what the problem was. I'm not sure if there are any sensors on the wheel hubs for CC that might be nudged by the 18"s. Are you getting any rubbing on your arches from the tyres?

 

[Thmsshaun]

No rubbing, nothing at all. I am sure it must have been OK or I would have noticed it. But I really cant remember if I have use it at the said speed since putting the 18's on.


Not had chance to check tyre pressures yet. It has been loaded up to the gunnels a few times recently though.

Going on a run over to shropshire in the morning well in err 5 hours time

All being well nice clear roads.

 

[rs2000]

Are all of your tyres worn to the same tread depth?

I had this problem on my W203 with new rear tyres but fronts worn down to 2.5mm.

Paul

 

[Thmsshaun]

Backs are more worn than the front Pressures all good.

 

[KLP 92]

What size tyres are you running? Its a common problem on the Merc if you increase the rolling diameter of tire.
I have the same problem on my C class since putting one size bigger tyres on my C class.

 

[Thmsshaun]

I am running the AMG Styling II staggered set up 225/40/18 on the front with 255/35/18 on the rear.

Is there anything you can do about it or is it something I need to live with?

Guess it keeps my licence safe anyway.

 

[Stratman]

Using the Tyre Size Calculator shows only a 0.2% speed difference between the sizes. I doubt that would cause the problem. Unless someone knows better ?

 

[Thmsshaun]

What size tyres are you running? Its a common problem on the Merc if you increase the rolling diameter of tire.
I have the same problem on my C class since putting one size bigger tyres on my C class.

Does the problem occur at the same sort of speed as what I described?

 

[sasha]

i have EXACTLY the same problem as originally described at the start of this thread. Cruise works up to 80 and then cuts out, in fact it works up to 3000 rpm and then cuts out.

i have just had a new passenger side tyre put on and so I am assuming that this is the culprit.

Did anyone get to the bottom of this problem?

It sounds like it could be:

- different tyre circumferences on fronts
- cc pcb board
- brake sensor

any ideas anyone?

 

[rs2000]

I'm pretty sure it's to do with differing tyre diameters. In my case, the fronts were well worn but the rear tyres were new. Replacing the front tyres cleared the problem. They were all the same size and make of tyre.

Strangely, the stealer had never come across the problem before!

 

[guydewdney]

In my experiance - worn tyres, or low presure are equally to blame.

But im lazy and havent read three pages of replies...