Author Topic: Cold start wiring  (Read 2364 times)

col320ce

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Cold start wiring
« on: April 12, 2020, 14:59:53 »
The cold start was disconnected on my 250se w111 and the SL wiring diagrams gave it as black/white/pink. The only wire that is likely to be the candidate is a black and white cable (se picture). Is this likely to be correct?
Thanks again!
Col

1964 230SL
1965 250SE coupe
1993 320CE Sportline

Aaron h

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Re: Cold start wiring
« Reply #1 on: April 13, 2020, 02:18:41 »
I've looked at W111, W112, W108, W109, and all W113 cars.  All schematics show a SW/RS/WS colored wire going to this electromagnet.  Though, given the close proximity of this wire to the electromagnet I'd feel comfortable assuming it's for the electromagnet.  Put a test light on it and crank the engine while cold and see if the test light comes on while cranking.  This is assuming that your thermo time switch is connected and in a somewhat operational condition. 

col320ce

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Re: Cold start wiring
« Reply #2 on: April 13, 2020, 03:34:26 »
Hi Aaron
I'll do that... Too much is disconnected at the moment to try it now...
Col

1964 230SL
1965 250SE coupe
1993 320CE Sportline

lpeterssen

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Re: Cold start wiring
« Reply #3 on: April 15, 2020, 12:00:00 »
Dear Col320ce

There is something you can do to be sure if that cable belongs to the injection pump mixture control solenoid without having your engine ready to fire.

That is to test continuity between that cable and the relays on the w111-250SE firewall. Check relays 20 and 21 shown on diagram attached for continuity between your black cable and terminal labeled 87 on them.

There should be continuity on relay 21 terminal 87.  To know which of the relays is number 21, just count the cables attached to its Bakelite connector.  The one that has 4 cables instead of 6 (both have 4 pin Bakelite connector, do not confuse it with a 6 prong relay) is the one that you are looking for.

Enjoy your investigation.

Best regards
L.peterssen

col320ce

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Re: Cold start wiring
« Reply #4 on: April 15, 2020, 12:05:50 »
That's a great idea!
Looks pretty straightforward too
Thanks!
Col

1964 230SL
1965 250SE coupe
1993 320CE Sportline