Gentlemen,

Could someone tell me where is the Decell switch on an 86 16V? I would like to check it out.

I've been having high idle problem around 1500rpm, and today I noticed that as I turned on accessories, heat blower, lights, etc.. The more accessories I turn on the more drop I get from Idle. This seems like an electrical problem. Does any 16V owner out there experience this?

Thank you for your help.
Alex

As far as I know the 16V has the same setup as other contemporaneous Merc engines. There is a switch on the end of the throttle shaft on the throttle body under the air flow meter. It should open/close as the throttle just moves off the idle stop.

The switch itself is difficult to reach, but it should have a pigtail that you can disconnect from the harness to check it for function.

The throttle shaft switch works in conjunction with the microswitch on the linkage to tell the ECU when the throttle is in the idle position.

I had an idle problem on my 190E 2.6 and it was a sticky throttle position switch. I was able to clean it off with mineral spirits from a spray bottle to where it functioned properly, then gave it a shot of WD-40. That was about 18 months ago. No problem since.

Duke

Thanks Duke2.6, I'll give it a try tomorrow.

Alex

I have question regarding the Decell switch functioning-

When I lift my foot off totally the gas pedal there is a slight hesitation before I feel the Decell switch cut off the fuel. Is this normal?

(My car is an 8v as opposed to a 16v).

Haasman

__________________
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)

Yes, there is a one to two second delay before the fuel shuts off after the throttle in closed, which appears to be programmed into the ECU.

I believe it is there to prevent jerking if you are just feathering the throttle. Also, for the fuel to shut off, both the TPS and linkage microswitch must be in the right position, which I think is closed for the microswitch and open for the TPS.

Duke