Hi.
I have a 2005 SL500.
The engine idol seems to be a bit high at 600-650rpm.
Does anybody know whether the idol can be adjusted. I am told it can't.
Thanks.

 

Is it an American Idol or no?

If you mean Idle, I don't think you can.

 

600-650 rpm is the correct idle for M113. It varies a little depending on the coolant temperature and other factors. Idle has not been adjustable since the introduction of ECU’s on all cars.

 

I believe you can adjust idle with a SDS, and developer mode, but if it’s the right RPM I wouldn’t bother.

 

Haha. Yes sorry idle not idol.
Thats sounds like what I had been told but I wanted to check with MBWorld.
Thanks.

 

Actually, many cars with electronic fuel injection had adjustable idle speeds when they used a hardwired throttle. They had set screws that adjusted the throttle butterfly closed position, just like in the old carburetor days. The drive-by-wire throttle is when any mechanical idle adjustment went away. As kbob said, you can adjust it with SDS. There are adjustments for idle speed both in park/neutral or in gear. My CLK's M273 engine would idle just a bit roughly in drive with hot weather so I bumped it up by 75rpm to smooth it out. Likely it was due to the crappy "summer formula" gasoline we are forced to use.

 

Thanks Rodney but what is SDS.

 

SDS = Star Diagnostic System (aka Star / Xentry)
Laptop with OBD2 connection used for all electronic and mechanical troubleshooting, and adjustment. A must have tool for this car.

 

Thanks mate.