RPMs drop then engine stalls when fully turning steering wheel

[PSB]

I have a 230 , automatic with power steering. I'm very mechanically  illiterate !  When the car is at a standstill and I'm doing maneuvers the RPMs will start to drop as I turn the steering wheel and the engine will stall. If as the RPMs start to drop I quickly start to undo the steering turn the RPMs increase again. In P the RPMs are close to 1000.   When I put in R or 2 they drop to about 600. As I turn they just get lower. Makes maneuvering a multiple stall and restar event. I need to keep the revs higher by pressing the accelerator even when shifting from P into gear. Obviously bad because the car "jumps" into gear and dangerous to control sped and movement. This, stalling, does not happen  when driving normally, stopping at traffic lights as the wheel is not being significantly turned. Once the engine is at normal temperature (170/180 F) it gets worse .  I can't see a logical connection between stalling and extended steering turn. Any inputs ?
Regards
Pedro

[Jonny B]

I believe there is a connection to the power steering that is supposed to increase (?) the idle as the steering is turned. This is on later 250 SLs and early 280 SL cars (Oz has this set up on his car).  Somehow linked with the constant speed switch on the throttle linkage. Not sure how this would fail or cause the issue. But probably worth taking a look.

I did a bit of searching using "steering idle" in the main search page - but without the quotes. This is the search accessed by the link to the left of the "Home" button above. The search in the upper right only searches the forum you are reading at the time.

There were three pages of items, but the first page had further information and some photos on the set-up.

I am way out on a limb on this one, I just remember there is some type of connection. Need more help on this.

[Pawel66]

In early 230 automatic it could be that the device on the picture is faulty perhaps. Do you have this device?

Experts will chime in, but I think, if it is not for the device I am showing, what you describe may aslo be caused if you have something gettng stuck so that it takes too much power to turn the wheels.

But if you have the device as on the picture, maybe it needs to be adjusted or repaired.

[kampala]

Jon is correct that my later 250sl (manual trans car) has a hydraulic line that actuates a cylinder when the power steering is cranked to increase the idle a touch.   However when disconnected, it does not make much difference.   We have seen this device on on later 250's and we think some early 280's.

I can't take a photo of it as the 250 is away in storage at the moment.

Nevertheless, I believe the 230's did not have this, so your issue is most likely something else.    Hopefully others will have some ideas on why your RPM drops so much. 

[Cees Klumper]

Poower steering pump bad, putting major drag on the engine when 'activated'? Idle should be around 700-800 RPM, in or out of gear. Do you have the constant speed solenoid?

[ja17]

Hello Pedro,

You should be able to idle at 650-700 rpms out of gear with a warm engine. 1,000 rpms when the engine is cold is also OK. Some cars have a hydraulic device or vacuum dashpot to keep the idle nice and even, in gear or out of gear. Poor linkage adjustment, injection pump mixture, improper ignition timing and/or low compression in one or two cylinders are things more likely to cause stalling problems.

[PSB]

Thank you all for the quick responses.
I will collect this information and pay the mechanic a visit. See if he can check through some of those "options".


Regards
Pedro