Ballast ign mod.

[A Dalton]

<<The Inj Pump Solenoid (under a HOT start condition) would only be activated for 1 second instead of the full cranking time...probably not a problem. It would be controlled by the TTS under Cold Start conditions.
>>

 Which is fine .. the 230 had the 1 sec reay and the 250 did not .. they later found that the rack sol was not needed , but they modified the system again and went back to the 1 sec relay system of the 230.. So, you lose nothing by having the rack sol working off the TTS..
There were 3 changes and the best change was  when we added an override in the cabin...  In all actuality , the most important part of start comes down to the CSV,,,,and the 1 sec relay solved most of the later hot start problems.  Turns out that the 230 system was best , but the pump itself needed a little cleaning up in the design of the cone check valves , which were changed to ball valves .. that is when the rack sol was found to no longer be needed .. I personaly prefer the early pumps , as I do not like crankcase oil in my pump.
...but if I were not a Tech, I would prob not be concerned with it.

[hands_aus]

Hello Arthur,
Today I used a secondhand spare MB SPST relay (from my box of bits) to 'test' the arrangement you supplied.
I picked up 12V from terminal #86 of the Inj Pump Sol. (It is the other end of the 'G' wire of the TTS, allowing me to conceal the wire next to the wiring harness.)
The other connections were made as per your diagram.

After allowing the fuel pump to prime the system for about 15 seconds, I then switched the cold engine on.

The start was VERY lively indeed!

I think this would be an excellent addition to cars in cold climates.

For my car the MB relay is not a good candidate for this project. As you suggest the smaller relay could be mounted behind the ballast resistor.

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

[A Dalton]

Very Good.. glad you see the difference.
 As I said , they made all those fuel related starting mods , but for some reason , they were Johnny-Come-Lately on addressing the  ballast
by-pass..
..The G circuit can be tapped anywhere you find convenient, as the relay Isolates the input from the ignition, so you are fine where you have it.........

[Ben]

Arthur, can you please advise me if the following relay is suitable. I realise the amperage is higher but it seems to be the only one that is locally avaialable !

http://www.radionics.ie/cgi-bin/bv/browse/Module.jsp?BV_SessionID=@@@@2074979525.1130147681@@@@&BV_EngineID=cccfaddgddelhmmcefeceefdffhdgmn.0&cacheID=ieie&3307601059=3307601059&catoid=-333617711

..........thanks !

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

[A Dalton]

Bad link....

[Ben]

Sorry Arthur, the website is www.radionics.ie, part # is 349-2137

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

[A Dalton]

That one does not work either....You have to drop the comma to get to the site...
 When posting sites , I always leave a few spaces  on each side so the hyperlink does nor include anything on each side ..
 Anywart, that will work .. a little heavy , but that is OK too,, good contacts are better than so/so ones...it has a Flyback resistor circuit built-in , so that is a nice relay.. only thing i don't like is it does not have a mounting tab . but you can take care of that...
.. you might want to see if they also have latching style relays so you can modify your high beam flasher to the stalk.....

[Ben]

quote:That one does not work either....You have to drop the comma to get to the site...
When posting sites , I always leave a few spaces on each side so the hyperlink does nor include anything on each side ..
Anywart, that will work .. a little heavy , but that is OK too,, good contacts are better than so/so ones...it has a Flyback resistor circuit built-in , so that is a nice relay.. only thing i don't like is it does not have a mounting tab . but you can take care of that...
.. you might want to see if they also have latching style relays so you can modify your high beam flasher to the stalk.....

...........jeeeez sorry about the link !

Anyway thanks for checking it ........and for reminding me I had another relay to buy ! I may aswell do the two jobs at the same time...........after I sort out my battery problems.............flat again this morning ![!]

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

[Ben]

Sorry to be a pain but I found a relay in an old parts box, which has the following terminals, I cant find out on the web an diagramatical info, 30, 85, 86, 87, and another 87 !

Can this be used for either mod ??

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

[hands_aus]

Hey Ben,

30 = 12V input for the coil
85 = earth for coil
86 = input to contact
87 = output from contact

test the resistance across 30 and 85 should be about 30 ohms + or -
test resistance across 86 and 87 should be infinite maybe meg ohms, but when operated should be 0 or 1 ohms but no more.

test to see if there is continuity between both #87 terminals, could be just common connections.

The relay is 'similar' to the one I used to test the setup on my 250, worked a treat but no where to mount it.

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

[A Dalton]

<<test the resistance across 30 and 85 should be about 30 ohms + or -
>

 That is incorrct.
 The relays contact set is 30 and 87 [ secondary load circuit]
 The relays coil terminals are 85 and 86  . These are the terminals that you want to see 30 ohms [ approx] across.
All Benz relays use 85/86 for relay primary circuit [ actuating coil]

 So, on the schematic I posted, the ballast gets shunted with terminals 30/87 and the wire from the TTS and ground use terminals 85/86.  Polarity is not important on this project.

[Ben]

Mmmm thanks Bob !

I have checked it on the bench and the relay works fine. It seems that I need to connect as follows,

85- Ground
86- Terminal G
30- Ign "+"
87- Coil side of ballast

Making and breaking 86 @ Terminal G opens and closes the relay !

Does that seem okay ?  Also I tried this on the bench using a good 12 volt supply. Now my question is what voltage will I get at Terminal G, because I checked it with a meter and I got very low voltage. However I then realised my connection there was loose, very loose, not helping my cold starts AND interferring with this test.

It was at this stage just now I was called away to the phone so I wont be able to retest 'till tomorrow.

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

[hands_aus]

Hey Arthur, Ben

sorry to mislead you

Ben, seems like you have it sorted.

You should get 12V at TTS terminal 'G '
If you have been having cold start problems it is possible that the low voltage at TTS Terminal 'G' has not been actuating your cold start relay.

Maybe you should test all your ignition and cold start connections.

You may not remember but I had stumbling on the freeway doing 100Kmph all because of a loose connection on the ballast resistor. There were no small sping washers but there are now.

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

[Ben]

Yeah good stuff Bob !

Thanks to Arthur also !

I will actually clean and test all my connections and earth straps and then wire in the relay.I need to check my charging circuit and the battery itself first !

I am actually getting under 7 volts at the coil when cranking from cold, having sat overnight.

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