toggle switch attached to csv and starter solenoid

[German Dude]

Hi Pagoda friends and experts,

I haven't participated in a while but do visit the forum frequently. I have read many a line on csv leakages resulting in poor gas mileage etc. I guess my situation is fairly unique. Allow me to describe:

There is a toggle switch in my glove box, with on/off positions. Clearly not original. I noticed it when I bought the car in 2004 but never thought much about it nor cared to check what it did.

Well, I know now: One wire is going from the toggle switch through the firewall to the csv solenoid (it shares the terminal at the upper back portion of the csv with a black/white cable which vanishes within a wire harness, the other toggle switch wire is going through the firewall to the engine starter solenoid.

Clearly, this was not installed by our Sindelfingen friends. But whoever did this - why did they do it?

I did a voltage check on both ends of the toggle switch, with the switch in both positions: Nothing. Ignition off, ignition on, engine running: absolutely nothing.

However: No volts at the csv either! I know next to nothing about electrical systems, but shouldn't there be voltage at the csv with an engine that was just started from cold?

Here is my attempt at an explanation: I know that the injection pump thermostat and warm running device was replaced some time ago - you can tell by the surface of the thermostat cover. Maybe, since the thermostat is so darn expensive (I have a 230SL), it was broken once and the above mentioned cable contraption was used to make sure the csv could be activated? And later they decided to go ahead and replace  the thermostat anyway, leaving the cables and switch in place? And due to constant strain on the csv, its solenoid gave out, resulting in the plunger keeping the csv open all the time, thus giving me such poor mileage?

Maybe I should have mentioned that my co reading is at 10% (my mechanic almost fainted when he saw the reading) and the adjustment screw at the head does not even begin to make a difference no matter where you turn it.

Feel free to corroborate my theory or blow it to pieces!
And: thanks for any input.

Best,


Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon

[al_lieffring]

quote:Originally posted by German Dude

Hi Pagoda friends and experts,

.......but shouldn't there be voltage at the csv with an engine that was just started from cold?


Best,


Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon

Jurgen

In a word, no.

The CSV is a start up enrichment decice, not a cold running enrichment. So it is only activated when the starter is operating. The earliest 230sl's had a different relay system to activate the CSV than the later cars with the Thermo-Time Switch. The early system operated the valve using a temperature switch that engaged the CSV the motor was cold and cranking, the later thermo-time switch also activates when the motor is cranking at cold temperatures, but also has a time limit function at coldest it will spray for 7 or 8 seconds (during cranking) then shut off, as the temperature increases the injection time is shortened at about 100deg (f) it will not engage at all during starting.

The toggle switch sounds like someone's manual controlled start up enrichment system, the valve will engage with the starter when the toggle is in the on position.
It is more common to find a momentary contact switch added to these cars, to give a second or two of spritz when pushed with the igniton on before the motor is cranked up.

I hope you are not too confused now
Al

66 230sl
Tour de Cure 50km unicycle ride to benefit Diabetes research.
http://main.diabetes.org/site/TR?pg=personal&fr_id=4372&px=2737950
Click link to sponsor my ride on May 20th.

[glennard]

Juergen,  This, your wiring, is another example of 'Shade Tree' engineering trumping MB engine management.  Come to Blacklick, OH for more skinny on FI.  That CSV has more explanations and wirings than Carter had pills.  No matter how your's is wired, it also gets air from  the temperature slide valve on the FI pump.  So, you have a potential for a really screwed up system.  A leaking CSV, a mystery glove box switch,   an unknown relay wiring of the start solenoid/thermo/time switch complex, a slide valve unknown, etc.  Wow

[German Dude]

Thanks for the answers.

I still have the hope that the leaking csv is the culprit and that the glove box switch and wires to csv and starter solenoid are simply add-ons that can be removed without tampering with the rest of the system.

Basically, other than the high co reading and the poor gas mileage the car runs great. I have suction at the injection pump air filter when cold, no suction when hot.

Well, it's going to the Mercedes Benz Meister this weekend. I will let you know what he found out!

Best,

Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon

[Ben]

Your CSv could be leaking no matter what way it is wired, or whether its working or not. The simple test is to loosed the little 5 or 6mm bolt on the side, and with ignition on, observe if fuel seeps out.

The limit is 3 drops per minute. If you see this much or more then the valve shouyld be replaced, or repaired, which is done quite easily and since the valves are expensive, its the best option.

Also the "adjustment screw at the head" is only the air screw and it wont have a huge effect on the CO, which must be adjusted via the screw at the rear of the pump, but only with the engine off. Its trial and error, switch off -adjust-check CO,switch off-adjust-check Co etc !

Good luck !

Regards,
Ben in Ireland.
'64 230SL 4sp.

[hands_aus]

The additional switch was (and still is) installed by people because the injection pumps often have problems with the ball valves/check valves allowing fuel to leak back to the tank. This leak back causes the driver to crank the engine for a prolonged period of time before the car will start.

The flash switch gave a shot of fuel into the inlet manifold which is enough to start the engine and let it run while the fuel lines to the injectors are refilled.

An MB option was an additional 'Time relay' which gives a 'one second' burst of fuel every time (hot or cold) the engine is started .

Bob Smith (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[German Dude]

Re the leaking valve: That's what I am thinking. I have already done the side bolt test. A lot more than three drops per minute. I know a rebuild or fix of the csv is in order. I still like to think that the toggle switch was in the "on"-position all the time, resulting in the csv being opened all the time and, in the end, getting stuck in the open position, and causing the leak.

thanks for the tip re the co adjustment at the fi pump! I will tell the mechanic not to touch it while the engine is running (His answer will no doubt be: "Do you think I am an idiot?").

Thanks again,

Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon

[TheEngineer]

The cold start solenoid (CSV)has a small tapered plunger that contacts a small tapered seat. That is a valve which closes off the fuel supply. As the thing becomes old the valve starts to leak. You can lap it in or even machine it carefully. It will be just like new.


'69 280SL,Signal Red,Automatic,retired engineer, West-Seattle,WA

[J. Huber]

To add to the Engineer's fine wisdom, the little guy also gets gummed up on occasion -- and simply needs a bit of cleanin' up.

James
63 230SL

[German Dude]

Well, then let's hope for the best.

Thanks, Herr Huber and others!

Best,

Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon

[Ben]

Just to add, if the switch was "ON" and the CSv open all the time, the car would not run in this condition.

I think your only issue is to remove/clean/and lap in the CSV valve seat. Its a simple enough job !

Continuing to drive with a leaky CSV will result in premature bore wear, as the fuel with wash the oil off the bores !

Regards,
Ben in Ireland.
'64 230SL 4sp.

[DavidBrough]

Just thought I should add a word of caution here. The CSV valve and seat are quite soft and you need to be very careful when lapping in as if to much metal is removed the valve will not seat properly and always leak.

I had a leak on mine I just could not seal and ended up sending the whole unit to our local UK specialists Roger Edwards Motors who promptly condemned it and wanted to know what heavy handed Herbert had been messing with it. I denied all knowledge of course but still had to find a good second hand unit on which I took their sage advice and used no more than T-Cut and gentle pressure. All is fine now, oops well at least it was until I made that statement.

Best of luck



David Brough
1969 280Sl Auto

[German Dude]

I am a heavy handed Herbert myself, so the car will go to my mechanic who is an extremely light handed Joachim. I will alert him to the softness of that thing. Thanks again.

He is currently restoring a 190SL. When you look at a bare-metal SL that old you can't help being amazed at the many traces of actual manual labor going into these cars' body work.

Best,

Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon

[TheEngineer]

To add to David's excellent advice: The female seat of the valve is very narrow when new, like about 1/2 mm. Both parts are brass and deteriorate over time & use. If you look at the seating surface under 14x magnification you will see what I mean. You can not restore a deeply pitted surface by lapping. You must take a light cut first. This is almost watchmaker's work. I used a countersink with a pilot so that the cut is square with the bore, and turned the tool by hand. The female seat is now wider, like about 3/4 mm. I tested for leakage using Dr. Benz'(Dan)method: Put some ATF in there and blow air from the other side. If it bubbles it's not tight!
Wer's kann, machts. Die Anderen reden nur davon

[German Dude]

Well,

I will pass this on too!

Wer's nicht kann, braucht jemanden, der's kann!

Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon

[glennard]

GD, Was ist los? (Penna Amish).   Translation, bitte(P A, also)

quote:Originally posted by German Dude

Well,

I will pass this on too!

Wer's nicht kann, braucht jemanden, der's kann!

Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon

[German Dude]

Well, The Engineer wrote in red:
Those who can do it will. The others just talk about it.

I added (in German): Those who cannot do it need someone who can!



Juergen
64 230SL #2933, 4sp, signal red, white hard top
2000 320 CDI Station Wagon

[German Dude]

A HAPPY END - AND A HEARTFELT THANK YOU!!!!

I started this thread over a year ago talking about funny csv wiring and poor fuel economy.

 To cut it short, here is what was done to the car:

1. New plugs

2. Fuel was leaking through the csv solenoid; solenoid was replaced

3. Fuel linkage was way off - I did the excellent fuel linkage tour (including changing the balljoints and shaft bearings)

4. Oil in the IP changed

5. Thermostat in the IP checked

6. Air filter on IP cleaned

7. One shim removed

8. WRD plunger unstuck

8. Distributor felt received a few drops of oil (which also cured the stutter at partial load)


A few months ago, I would never have thought it possible for me to attack - and solve - the problem myself, but with the abundance of information this forum holds - and shares freely!!! - I was able to get from 12 mpg to 19 mpg.

So here is a heartfelt Thank you and Danke schoen.

[rwmastel]

Juergen,

Did you end up removing the "custom" switch in the glove box?

[glennard]

Juergen, The MB glovebox manual for 250SE coupes says over 22 mpg for a heavier car.  Should we be getting 25 mpg?

[German Dude]

Ah, the custom switch.

It was easy enough to de-install, and I don't need it. The car fires up immediately hot and cold and runs great.

Re the mpg: So 25 is what I should be striving for? I just got her up to 20 from 12, so another 5 may be within sight. With gas prices in Germany at $9/gallon, I have every motivation to get her there.

[rwmastel]

quote:Originally posted by glennard

Should we be getting 25 mpg?

I've never heard of a Pagoda doing that.  20 mpg is excellent.

[glennard]

Guys, Take a look a the 'fuel consumption' curves in the glove box manuals.  The 220SE got 30 mpg- per MB- at lower speeds!!  Must have been better gas back in the 60s.   The 'oil consumption' calls for 0.2 litres per 100 km or about a quart every 300/400 miles.  Maybe burning oil gave better mileage?

[German Dude]

Well, we haven't done a co test since the repairs and changes.

Should be interesting to see how that reading has changed (I had a little over 10% before the quest started...). I will post the results as soon as I have them.

From the exhaust smell I get a feeling she's still running rich, and since we are about to pass the 10$ / gallon threshold I get the feeling that I am running poor.