Pagoda SL Group

W113 Pagoda SL Group => Drive train, fuel, suspension, steering & brakes => Topic started by: jedwards on May 14, 2014, 06:06:17

Title: Slow (or weak) CSS
Post by: jedwards on May 14, 2014, 06:06:17

Gentlemen,
My Constant Speed Solenoid or CSS  on my early 250SL Auto,  comes on rather slowly,  over a 2 second period.  Is this normal?
I appreciate that it has a lot of work  to do in moving their entire accelerator linkage mechanism, but if its is slow, it might also be weak, somewhat explaining my in gear idle variability.

Should it slam on like normal solenoids, or is it a supposed to be a more gentle process?  Is there a technique for testing it?
Does anyone know how to dismantle a CSS?  If I can get it apart, I can rewind and restore it.

Many thanks in advance.

Title: Re: Slow (or weak) CSS
Post by: ctaylor738 on May 14, 2014, 11:49:04

IME, it is instantaneous, as soon as it gets power via the pressure switches on the transmission.  The switches rather than the CSS may be the problem.  Is there less of a problem in reverse vs. forward?

Title: Re: Slow (or weak) CSS
Post by: Cees Klumper on May 14, 2014, 16:32:56

It should be immediate. Not sure how you would open one up but if you figure out an economic procedure to restore these, it would be very welcome to the Pagoda community.

Title: Re: Slow (or weak) CSS
Post by: jedwards on May 15, 2014, 00:33:59

Thanks for the help.

Where is the pressure switch located?
Is there a test procedure or method for the switch to determine if it is working properly?

Title: Re: Slow (or weak) CSS
Post by: wwheeler on May 15, 2014, 19:45:17

You also might look at the linkage and make sure it is well lubricated. There are a couple of bell cranks especially the one below the manifold that get sticky over time. I ususally oil the entire linkage once a year. I use a micro oiler to get into the tiny crevices.

My CSS is immediate as well. In fact when I shift into gear, the idle speed doesn't change at all.

Title: Re: Slow (or weak) CSS
Post by: ctaylor738 on May 16, 2014, 01:03:30

There are two pressures switches, one for forward and one for reverse.  They are located on the lower front sides of the trans.  They both have metal lines and wires running to them.

Title: Re: Slow (or weak) CSS
Post by: wwheeler on May 16, 2014, 16:46:34

Sorry, I didn't see the question about how to test. The switches work by providing a ground when pressurized. So take off the lead wire and you can test to see if the post has a ground when the switch is pressurized. The switch body is grounded by the trans housing. Make sure your ground wire to the trans is good.

Might run a jumper wire to the post so you don't have to climb under the car when its running.

Title: Re: Slow (or weak) CSS
Post by: ctaylor738 on May 16, 2014, 19:21:32

Running, and in gear!  Not a good time to be under the car.