CSS and double solenoid problem

[rgafitanu@gmail.com]

Hello,
I placed a camera in the tunnel to see the double solenoid linkage and I realized that under reverse or drive the linkage was moving back to the middle position. Apparently the idle speed circuit is shorting or interfering with the double solenoid circuit. I believe that the idle speed increase circuit is separate/independent from the double acting solenoid circuit. This means that at idle when the solenoid rod is moved back it shouldn't come back to the middle position when shifting to reverse or drive.
I thought that the original wiring shorted so I used new/separate wires. But it didn't change the behavior. I loosened and tightened again the transmission ground strap. I think I am left with:
- pressure switches don't make a good ground, finding another path through the 3 position solenoid making it release the rear position set by the idle switch.
- the 3 position solenoid blew its insulation and while still functioning correctly may be affected by that and malfunction.
- one or both of the pressure switches blew the insulation, still function but creating the malfunction.
Anybody has seen something like it?
Would diodes as mentioned here across the solenoids coil help with this problem?

[Paul & Dolly]

Have you checked the operation of the Rotary switch on the throttle body ?

Pagoda SL Group » W113 Pagoda SL Group » Drive train, fuel, suspension, steering & brakes » Bad Upshift on light Throttle (Auto)

https://www.sl113.org/forums/index.php?topic=24794.msg177342#msg177342

see the post above

good luck

Paul

[rgafitanu@gmail.com]

A few months back I opened the idle switch and cleaned it and it works very well.

[cfm65@me.com]

Hi Radu,
Yep, they are two differnent circiuts with differrnt functions. The CSS or idle speed increase as you call it should only work when selecting D or R while engine idling and standing still. The two pressure switches are inter connected and a red/ green wire(in my car) goes from the CSS to the LH pressure switch. This is an earth wire, however if you test both wires at the CSS, they will both SEEM alive, but as soon as the engine is running and D/R is selected one of the pressure switches will go to ground and the CSS will extend and increase idle speed.
During all this, the 3 way switch will be pulled down( decreasing gearbox pressure) in order to ensure soft switching into D or R. Soon after opening the throttle the throttle valve on the ventury will release and the 3 way will go to the middle position and restore normal gearbox pressure to ensure positive switching without slipping. In other words, engine idle in any gear, 3 way solenoid down, soft switch and soft pull away( no clungking no jerking.
Throttle open, 3 Way in the middle, normal driving.
Kick down will increase gearbox pressure in order to automatically select a lower gear.
I hope this clears your confusion re 3 way and CSS functions.
Regards
Chris

[Benz Dr.]

 I think that sometimes the throttle switch isn't adjusted very well and when the CCS solenoid is activated the throttle switch has to be adjusted to compensate for this extra throttle opening. I use a test light to check when the light is on and then adjust the switch until the light goes out. Engine must be fully warmed up and in gear to adjust the throttle switch or it may not work right. I wouldn't look for problems with anything else until you get this adjustment right first.

[rgafitanu@gmail.com]

I feel like a fool after Chris, Joe and Dan directed me to the idle switch. I did clean the switch but I adjusted it at idle in Park as I was moving around the car. In Drive or Reverse the CSS pushes the linkage and the butterfly a few degrees enough for the idle switch to open releasing the 3 way solenoid from its rear position.
I adjusted the idle switch with the CSS pulled out and now everything is good.

[cfm65@me.com]

Great, and well done Radu.
THE CREDIT GOES TO JOE AND DAN. I mearly noticed the misunderstanding, only because I am struggling with the same issues.
Regards
Chris