The Happy Idiot

[PaulMason]

I find that some people I meet don't like to ask "the happy idiot" question in public for fear of making themselves look a bit dim. I happily embrace, that on matters of Mercedes (plus so many more topics) I am, as a relative newcomer, very dim by comparison to the wealth of knowledge and experience on offer via forums, hence happy to ask the seemingly daft questions....

1) Does ambient temperature effect a turbo actuator (or similar problem)? My car (2009, W221 S320 CDI, OM642 engine) has an oddity which has put it into limp at times. Switch the engine on and off and all is well again It is potentially/maybe (to be established yet) a turbo actuator fault based on experienced feedback of the symptoms (there is no fault code). When it was warm weather (20c plus) this happened reasonably regularly, since the weather has cooled, happened only once (on a day when it was more than 20c ). Can ambient temperature affect a car and if so, does it point to anything particular? I haven't done anything to investigate my symptoms further and am now thinking (my instrinsic laziness coming out) I may get a grace period of cooler weather to focus on other things ?

2) Can different keys affect how a car runs? My car came with 2 keys. My best guess is 1 is original, based on wear, and the other is a replacement. With the original key, the car seems to run smoother and deliver power more effortlessly. Is this actually possible or is it my imagination playing tricks on me?

Thanks in advance!

 

[SpikyMikey]

From one Happy Idiot to another-
Firstly, have you had the codes read on STAR, or a generic code reader?
Secondly, generally, engines prefer it when the weather is cold; cold air is denser than warm air , therefore you can get more oxygen into the engine to combine with the fuel.
Thirdly, apart from setting the seat/mirror/steering wheel adjustment (if your car has memory facility on the keys), the key can't make any difference.
Although a 'performance key' option sounds like quite a handy thing

 

[PaulMason]

From one Happy Idiot to another-
Firstly, have you had the codes read on STAR, or a generic code reader?
Secondly, generally, engines prefer it when the weather is cold; cold air is denser than warm air , therefore you can get more oxygen into the engine to combine with the fuel.
Thirdly, apart from setting the seat/mirror/steering wheel adjustment (if your car has memory facility on the keys), the key can't make any difference.
Although a 'performance key' option sounds like quite a handy thing

Thanks Spiky. Not read on a Star, but I did treat myself to an iCarsoft V3 MB, so was hoping that may have spotted something, if indeed it did prompt a code. Get the cold dense air, just wondering if ambient can effect something like the turbo actuator or the likes of a MAF etc (although my judder/kangaroo/limp combo do suggest likely to be the actuator).

I am going to continue to use the "original" key as even if it's in my head, that now is the "performance" key!

 

[SpikyMikey]

iCarsoft seems to be one of, if not the best aftermarket readers, so I would imagine it would find any issues. I'm sure someone on here with experience of the OM642 will be along shortly with some ideas.
The keys that came with my C Class were obviously a 'master' and 'spare'; one was pretty much pristine, the other looked like it had been dropped, stood on and kicked about a 1000 times. Unfortunately the pristine one doesn't have the performance option installed

 

[AndrewOl]

It could be the slight increase in air density but I doubt it. If it is you should be able to provoke limp mode by driving the car on boost for a bit. The inlet tract will soon get nice and hot and if the actuator is struggling (or the turbo) the boost will fall off and you will trigger a cel.

 

[DITTRICH]

Temperature affects electrical circuits due to expansion and contraction of metal parts. There are so many electrical bits in cars these days, that a 14 year old car jammed with electrical sensors that gradually degrade and go out of spec...

 

[Larkone]

My issue with my turbo actuator (OM642) was worse when the engine was hot after a long run. The gears collect dust and muck from the carbon brushes in the electric motor and this affects their ability to turn smoothly. You can open it and clean them, use a light wipe of high temp silicon grease. This worked for 30K miles but eventually I replaced the actuator after it started to show the same symptoms again with a refurbed one and the improvement to driveability and consumption was worth it. They are around £120 and its a simple 15 minute job to swap them over. I used Genuine Electronic Turbo Actuator for Cars | Turbovanes.com

 

[ChrisHGTV]

From one Happy Idiot to another-
Firstly, have you had the codes read on STAR, or a generic code reader?
Secondly, generally, engines prefer it when the weather is cold; cold air is denser than warm air , therefore you can get more oxygen into the engine to combine with the fuel.
Thirdly, apart from setting the seat/mirror/steering wheel adjustment (if your car has memory facility on the keys), the key can't make any difference.
Although a 'performance key' option sounds like quite a handy thing

I can't remember what car it was now but i recently saw a programme with a performance car that had two keys - and one gave increased performance over the other. Might have been Top Gear? I can't remember what the car was so it obviously didn't leave much of an impression!

 

[ALFAitalia]

Bugatti Veyron has that feature along with a few other super cars.

 

[ChrisHGTV]

Bugatti Veyron has that feature along with a few other super cars.

My Alfa has a kind of similar version. The only difference really is that one starts the car, and the other doesn't! (Luckily ive actually got 4 keys for it!)

 

[ioweddie]

The key learns your driving style...plus it will adjust the seats if electric...and various other things...the idea is if your 6ft and a racer the car will pick that up and set the seat and steering wheel etc to suit you...The other key is for your wife or other regular driver who may be sedate and 5ft tall...so the 2nd key remembers the setting adjusted by the shorter person...Try it.....use the 2nd key and move the seat closer ...lower or higher...and the steering wheel up high...drive round the block...then use the 1st key and it will adjust everything back where it was...clever