Author Topic: Stalls when braking  (Read 5396 times)

adamigor

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Stalls when braking
« on: December 14, 2013, 04:54:49 »
Hi Friends
My 1971 280sl drives like a dream EXCEPT
When I brake for a stop sign or light. The car stalls when it comes to a stop. If I give it a little gas then it stays running. Otherwise it stalls and it needs to be started again. Any tips for solving this?
Thanks very much

ja17

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Re: Stalls when braking
« Reply #1 on: December 14, 2013, 05:22:49 »
Could be a engine linkage problem or a linkage input (constant speed solenoid).  "The Linkage Tour" is a good place to start. We could use a little more history on the problem. What is the idle speed in park with warmed-up engine? How long have you had the problem? Is the engine in good tune?
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

Louiehenry

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Re: Stalls when braking
« Reply #2 on: December 14, 2013, 06:28:34 »
Have you tried replacing your plugs and oil? Mine was doing that for a while, changed those things, never had it happen again!

Flyair

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Re: Stalls when braking
« Reply #3 on: December 14, 2013, 07:51:45 »
think also about replacing filters (especially the fuel one).
Also, how about your idle rev level? 
Stan
1971 280SL
2011 SL550 AMG
2011 GL
2015 GLA

adamigor

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Re: Stalls when braking
« Reply #4 on: December 14, 2013, 19:38:35 »
the engine idles at 1200 rpm.  i had the car tuned a year ago.  i will hunt down all of the items on the suggestion list this coming week and report back to the board with my findings.  this has been extremely helpful.. Thanks to all

Cees Klumper

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Re: Stalls when braking
« Reply #5 on: December 15, 2013, 08:11:37 »
1,200 RPM is too high for idle; I think 700-800 is the goal. Someone may have set it that high to compensate for a non-functioning idle speed solenoid (assuming your car is an automatic and/or has AC considering your location). It's easy to check, and these solenoids are still available, I replaced mine a couple of years ago. Lots of info on the site on how to check, set etc. Good luck!
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

ja17

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Re: Stalls when braking
« Reply #6 on: December 16, 2013, 01:35:57 »
Could also be the venturi not closing, because of linkage issue or the stop screw improperly set.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

stickandrudderman

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Re: Stalls when braking
« Reply #7 on: December 16, 2013, 16:58:11 »
For automatics the idle speed solenoids are NLA AFAIAA.
If the car in question is a manual and it has a vacuum cell on the inlet manifold then the function of that vacuum cell is to delay throttle closing on over-run. Failure of this cell causes cutting out on over-run.
1200RPM is way to high. 800 is ideal.

Cees Klumper

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Re: Stalls when braking
« Reply #8 on: December 16, 2013, 17:48:57 »
For automatics the idle speed solenoids are NLA AFAIAA.

Indeed SLS has this as not available; seems I may have got one of the last ones?
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

garymand

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Re: Stalls when braking
« Reply #9 on: December 17, 2013, 18:12:06 »
Does the RPMs change when you press the brakes?
Gary
Early 250SL German version owned since 71, C320, R350, 89 Porsche 944 Turbo S