Author Topic: venturi valve and switch, also e-brake  (Read 5159 times)

Ed Fisher

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venturi valve and switch, also e-brake
« on: August 31, 2004, 07:00:19 »
Good morning all:

Well, after reading through the search engine I now know that the venturi valve is what is commonly known as a throttle body these days.  I was confused, and reading the big blue service manual has not helped much.  I have to get a little more familiar with terminology and location to do any real work.  
Question #1:  What I believe to be the switch on the venturi valve (black bakelite, two terminals) is not connected electrically to anything.  Where are the wires that should be connected here supposed to originate?  This car has been jerry-rigged in the wiring category.  
Question #2:  What color are these wires?  I have some that are zip-tied together and not terminated, I have others that are spliced into the harness and going who-knows-where.  This is going to take a while to figure out.
Question #3:  The plunger on the transmission is moving freely, but I don't expect it to work well with no hook-up to the venturi switch, am I correct in this assumption?
Question #4:  When pulling the hand brake I can hold the vehicle from moving, but the hand brake will not "catch" the notched gear.  The button on the handle will not depress.  How does this normally operate, and is it just stuck?
Question #5:  I've got blow-by.  Can anyone suggest good, high detergent motor oil(s) that I can try for the infinitesimally small chance that I can un-stick an oil ring?
Statement #1:  I am sure glad y'all are out there, as reading the manual has only been enlightening on topics that I have seen discussed here.  I would have no hope of breaking the mysteries that are in front of me without this forum.  Thank you one and all.
Statement #2:  I have looked hard for the engine number, as has Will Samples, and there is not one on the block.  Will said that this means it is a replacement block directly from Mercedes.  I have an early 230SL, with the vertical spare tire and the VIN of 11304212003139.  Are there any other designators on the engine block that I can look for?  (I guess that was question #6…)

Thanks,

Ed Fisher Dallas, Texas

Cees Klumper

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Re: venturi valve and switch, also e-brake
« Reply #1 on: August 31, 2004, 14:08:11 »
Hello Ed. I take it you have an automatic transmission? Then the bakelite switch, AFAIK, is to actuate the constant speed solenoid that raised the idle RPM's. This solenoid is a straightforward device that only seems to need 12V to work, and it should only work when the gas pedal is pressed. I.e. when the throttle body switch is triggered. I imagine you could set up your own wiring to rig this up, although there is no doubt a better way. Best may be if you try to arrange with another owner (maybe through Will, please give him my regards next time you speak with him!) with a similar car to see how the wiring on his (or her) car is routed. Hopefully this covers questions 1 thru 3.
#4: try adjusting the hand brake lever with the round "nut" (with small holes where you can turn it) right below the handle. At least that is how it is adjusted on my 280 SL, yours might be different though. The button sounds like it might just be stuck.
statement #2 / question #6: you must have a replacement engine. Check the head to see whether it is actually a '230' engine for it could be a 250 or 280. From the outside, I am not aware of any physical markings that can tell you more about the engine block itself. Joe Alexander and I rebuilt a 280 engine block without a number last year, and it turned out to have the early-style 280 head design, but the later-style crankshaft bearing design ...
#5: Will knows a lot about these engines, rebuilds them etc. He might have some ideas on how to 'unstick' stuck rings. Other than an Italian tune-up, I can't think of anything off-hand :-(

Good luck, and others: please chime in here.

Cees Klumper in Amsterdam
'69 white 280 SL automatic
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: venturi valve and switch, also e-brake
« Reply #2 on: August 31, 2004, 20:57:03 »
Hello Ed and Cees,
The venturi switch operates the three position solenoid on the transmission. If this is not hooked up the transmission will not upshift or downshift properly. The car will have no kickdown passing gear also. It sounds like you need a good wiring diagram. It might be better to look at some other 230-SL's and take some good pictures.

The engine number on the 230-SL is on a small metal plate directly under spark plug number 5 and 6 on the engine block. If you do not have this plate but only a flat smooth surface this is a replacement black. You can identify the engine by the cylinder head number which is cast on the head between spark plug two and three. A 127 number indicates 230 series, a 129 indicates 250 series a 130 indicates 280 series. You can search up a lot more information on numbers try "cylinder head chart".

Joe Alexander
Blacklick, Ohio
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

Cees Klumper

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Re: venturi valve and switch, also e-brake
« Reply #3 on: August 31, 2004, 21:50:59 »
 :?

Cees Klumper in Amsterdam
'69 white 280 SL automatic
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

Malc

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Re: venturi valve and switch, also e-brake
« Reply #4 on: September 02, 2004, 02:22:09 »
Ed,
In reply to question 5...
Couple of routes to go
route 1
Buy some "flushing" oil and at least 2 filters. Drain the oil, add the flushing oil and new filter, run car at fast idle for 20 minutes or so, or take it out for a gentle drive.
Drain fushing oil and change filter, add "normal" oil

route 2
Drain oil and change filter add oil suitable for diesel or turbo diesel engine, 15-40W, 10-40W, 20-50W run that for a hundred miles or so or until the blow by stops.
Diesel engine oil has the highest detergent content yu can get without using additives.

Question 4
some possibilities here, either the button and mechanism is stuck, is the button "in"? THe link to the pawl has come adrift, or the pawl and ratchet is worn out.
Commonly lots of folk pull the handbrake on without pushing in the buttom so you hear it "clicking" this eventually wears the ratchet and pawl out.

Sorry I can't help with the rest of the questions, that's automatic transmission

HTH
Malc
Scotland

Ed Fisher

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Re: venturi valve and switch, also e-brake
« Reply #5 on: September 02, 2004, 09:57:24 »
Thanks everyone for the suggestions.  Malc, I will try the high detergent diesel oil first.  Thank you for that suggestion, it was exactly what I was looking for.  Anyone have any opinions on whether or not this will work?  Prayers?

Regarding the hand brake:  The pawl is not rotating freely and therefore the button is not moving it readily.  As of right now it has no hope of being actuated by the spring force alone.  I have sprayed Aero Kroil on the rotation points and have been able to tap it down to catch the ratcheting grooves and move it back up with significant pressure on the button.  After having done this 10-15 times I am now letting the penetrating oil soak and see if it makes a difference.  If not, I will have to disassemble the handle from the body and take it to the bench to move it with pliers of something as such.  Has anyone done this?

I am still unclear on the whole venturi switch issue.  I do have a kickdown passing gear and the auto trans shifts are not teeth chattering but merely abrupt, albeit with a clunk in the shifting down at a stop.  I think that the venturi switch must be hooked up, at least partially, or I would not have passing kickdown according to Joe's post.  Regarding the clicking that I am supposed to hear by moving the throttle linkage with key on: where exactly should I put my ear, and should I be able to put my hand on a specific piece and feel a solenoid engaging, or is it entirely electrical?  If so, where exactly?  

Oh, by the way.  I did finally find some rust!  Beneath the passenger side carpeting there is a little rust on the floor.  I think it is from the condensate from the A/C not getting out of the compartment.  That too was rigged with hoses that were not routed correctly. (sigh)  Anyway, I just had to share that with the previous poster who said that these cars will rust on the moon.  He was right.  There was no other significant oxidation anywhere else though, save a little scaling beneath the battery tray.  I can certainly forgive that on a 40 year old car.  If I had not read what a rarity it is to find a rust-free Pagoda previously I would be in a state of despair.  The car and I have not been getting along too well up to now.  While I was at the back of the car rummaging in a box the hot tailpipe extension tatooed my bare calf.  While I was getting ready to check something under the hood, still not used to the safety catch location, I almost ripped the ear off of my head on that same safety catch.  It hasn't been pretty so far, with oil leaks, wiring not hooked up, etc.  However, when the car is underway it really is a joy to drive.  Alas, a love/hate relationship.  

I'll change the oil as soon as I can and see how it goes.  

Ed

P.S.  I am sorry if I didn't reply to previous postings earlier.  I just learned to "subscribe to topic".

Naj ✝︎

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Re: venturi valve and switch, also e-brake
« Reply #6 on: September 02, 2004, 16:04:12 »
Malc,
Why not use detergent turbo-diesel oil full time?
Any problems??

naj

65 230SL
68 280SL
68 280SL

ja17

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Re: venturi valve and switch, also e-brake
« Reply #7 on: September 02, 2004, 21:26:11 »
Hello Ed,
The hard downshift should go away when you adjust your venturi linkage or venturi switch. When it is adjusted properly power will be going into the switch on one wire and leaving through the other (switch closed). This test must be done at idle in drive. the test can also be done with engine off in drive ignition on as long as your car does not have  a venturi vacuum dashpot holding the linkage off it's stop. If so remove the dashpot for the test or do the test with the engine running.
With the engine running it is hard to hear the three position solenoid working. It is sitting on top of the transmission bell housing. If your switch or venturi linkage is not set properly you will not hear it at all because it will not work. You can also remove the access cover on transmission tunnel ( passenger side ) and watch it work! Since the transmission kickdown is actuated by the button on the floor, passing gear should work even if the venturi switch is not set correctly.

Joe Alexander
Blacklick, Ohio
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

iceberg

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Re: venturi valve and switch, also e-brake
« Reply #8 on: September 03, 2004, 03:38:46 »
Hi Ed,
I can answer Q 4 for you.  I rencently took off my brake handle and had the same problem.  The mechanism that makes the brake handle stay up is actually a gear.  The teeth of the gear make the clicking noise.  This gear is a thin semi circualr plate that is held in place by a tensin spring, and when you pull the handle off, it is released and not sits 180 Degrees off. So all you have to do is take the handle off again, then turn the wheel 180 Degrees back and put it back in.  This will also make the release button pop back up again adn it will work fine then.  Since I am not familiar with the correct vernacular, I am attaching a quick sketch I made just for you. This will explain to you exactly what it is you need to do to get this going again. Actually tried but could not attach the image, so I will email it you.
Regards,
Hassan

Malc

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Re: venturi valve and switch, also e-brake
« Reply #9 on: September 03, 2004, 05:18:41 »
quote:
Originally posted by naj

Malc,
Why not use detergent turbo-diesel oil full time?
Any problems??
naj


Naj,
Not really, The only thing is that you would probably want to change the oil and filter every 3000 miles a couple of times as the high detergent content will "wash" the crud out of the engine and you don't want that circulating.
after that you should be ok with the more "normal" interval.
Oh, and turbo-diesel engine oil tends to be a little more expensive, however whatever oil you use make sure that it is up to a SAE/API standard.

cheers
Malc

PS where in the UK are you??

« Last Edit: September 03, 2004, 05:21:36 by Malc »