Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: davids on March 23, 2011, 16:10:14

Title: idle increase solinoid.
Post by: davids on March 23, 2011, 16:10:14

My idle increase solinoid has no wires going to it .From doing some searching looks like it should run to the kick down switch and the venturi control unit switch , have a 1971 280sl is this supposed to be hooked up? my idle drops when I use the a/c . Can anyone step me through in runing wires and hooking this system up. Thanks Also where are the kick down switch and the venturi control unit switch ?

Title: Re: idle increase solinoid.
Post by: graphic66 on March 23, 2011, 17:25:12

Check the schematics in the technical manual on this site http://www.sl113.org/wiki/Restricted/ColorWiringDiagrams   You need to be a member to view, best money you will spend on your car if you haven't already!

Title: Re: idle increase solinoid.
Post by: davids on March 23, 2011, 18:00:58

Why does the colored wiring diagram not have idle increase solinoid listed ,and also does not list kick down switch and these are the iteams i need.

Title: Re: idle increase solinoid.
Post by: Peter van Es on March 23, 2011, 18:13:45

Check this diagram... http://www.sl113.org/wiki/uploads/Electrical/280slwiringdiagram.pdf for the 280SL with US modifications. The kick down switch is #53, Idle increase solenoid is #51.

Title: Re: idle increase solinoid.
Post by: davids on March 23, 2011, 19:01:10

Yes I found this diagram,but i need it color coded so i can figure out  how to hook up idle increase solinoid . Iam also wondering if my 1971 280 sl is supposed to have it ? Have owned the car since 1980 and it has never had wiring going to it.For the past seven years we have been restoring so just trying to get everything correct.

Title: Re: idle increase solinoid.
Post by: Larry & Norma on March 23, 2011, 19:50:40

My 1970 280SL has it

Title: Re: idle increase solinoid.
Post by: Peter van Es on March 23, 2011, 20:08:40

Sorry, as far as we know there is no colour coded version. You'll need to trace the wires.

Peter

Title: Re: idle increase solinoid.
Post by: ja17 on March 24, 2011, 03:19:34

Hello,

These "Constant Idle Solenoids"  (CIS) were used in conjunction with the hydraulic pressure switches on the automatic transmissions in the W113 cars with automatic transmissions prior to 1970. Power was supplied to the solenoid any time the ignition was on through fuse #5.  The CIS was activated by switching the ground (earth) to the CIS on or off. This was accomplished by the hydraulic pressure switches on the automatic transmissions. One or the other hydraulic pressure switches are activated when the transmission is placed in a forward or reverse gear.  These hydraulic pressure switches complete the ground (earth) to the CIS thus activating the device to maintain a constant idle. The hydraulic pressure switches were robust enough to do the switching themselves without any relays.  In 1970 the function changed and only USA cars equipped with AC had functioning constant idle solenoids. With these later USA cars, when the AC is switched on, the CIS is activated. USA W113s delivered without AC had a CIS but it was never hooked up! In addition on the later USA cars, a vacuum dashpot was added to the intake manifold venturi to boost idle if the engine faltered on both the cars with and without AC.
I suspect that your W113 may not have been delivered with AC, in addition, most likely you will not have hydraulic pressure switches on your transmission. Do you have the vacuum dashpot on the venturi?

Joe Alexander
Blacklick, Ohio

Title: Re: idle increase solinoid.
Post by: 280SE Guy on March 24, 2011, 10:09:09

Here are the color coded wires on my 1971 280SE if it helps any:

Title: Re: idle increase solinoid.
Post by: davids on March 24, 2011, 14:59:52

How can I tell if my 71 280sl was built with a/c ?  I have a/c now and I believe it is original equipment,but do not know if it was installed afterwords.