Ignition w113

[Jasper82]

I am jasper from Holland. An have a problem with my sl please help me with following. My ignition switch was fall a part, and i fixed that with (i think)the right wiring schedule. But now the car won't start.
The spark plug only sparks once when turn of the ignition key. Do's any one now this problem. The car has transistorized ignition!

Kind Regards Jasper

[jeffc280sl]

Hello Jasper,

I assume your car is the later 280SL version.  Did the ignition system work before the switch fell apart?

Can you crank the starter motor over with the key?

My first thought is that the ignition switch may still be the problem.  Insted of providing continuous voltage to the ignition system it is momentary (one time).


Jeff C.
1970 280SL 4-speed

[Jasper82]

Hello Jeff

The car engine was running, but when the engine was running the start motor keeps starting. And yes i can crank the starter with the key.

thanks so far

[jeffc280sl]

Jasper,

Sounds like the wiring in the ignition switch to engage the starter motor and the engine run position are reversed.   The engine run position for the key should be an "on" position.  The key position for the start position should be an "on" mode only when the key is turned to the full clockwise position to engage the starter motor.

Jeff C.
1970 280SL 4-speed

[Jasper82]

Thanks Jeff,

But how can i check that? Do's any one have the right schedule for the ignition wirring switch.

Jasper

[jeffc280sl]

Jasper,

Do you have a wring diagram for your car?

The ignition wiring is fairly simple.  Turing the key to the accessory position allows the radio and other devices to operate.  The next sequence in the ley is the run mode.  In this mode power from fuse #1 is sent via terminal #15 on the key switch to the 4 ohm ballast resistor.  

The next sequence for the key is the start position.  In this position power from fuse #1 is sent via terminal 50 of the ignition key switch to the terminal 50 on the starter motor.  While thye key is in the start mode power will be provided to the starter and the starter motor will crank the engine.  As soon as the key is turned to the rum position the starter motor will stop cranking the engine.

If you can get the the rear of the ignition switch module with a multi-meter look for 12V on terminal 50 when the key is in the crank mode.    At the same time you should have 12V on one side of the 4ohm ballast. resistor.  As the key is turned to the run position 12V should disappear from terminal 50 of the starter switch and motor.  In the rum position 12V should remain on terminal 15 and one side of the 4 ohm ballast resistor.

(I have not mentioned the starter lock out feature for automatic transmissions, assuming it is working okay on your car)

Jeff C.
1970 280SL 4-speed

[glennard]

Jeff, The mechanical part of the switch(not the separate electrical part) might be the problem.  It comes out by itself.  These fail after many turns!

[jeffc280sl]

Glen,

True enough.  Do you have any docs that could help Jasper?

Jeff C.
1970 280SL 4-speed

[glennard]

Jeff, Working on a ladder kind of diagram that is easier to follow, in a decent form.

[Jasper82]

Jeff C

Do you have the right diagram?

Jasper

[jeffc280sl]

Jasper,

Do you mean the wiring diagram?

Jeff C.
1970 280SL 4-speed

[Jonny B]

Jasper,

Or do you mean the left diagram???

Jonny B
1967 250SL Auto

[Jasper82]

I mean the wiring diagram, sorry for my bad english

jasper

[Naj ✝︎]

Jasper,

#47 is the Ignition Switch



naj

68 280SL

[Jasper82]

Thanks for al the comments, I have been working on the car yesterday.
An checked al the wiring (like you guys told me) but the car still don't start. Is maybe the transistorized ignition the problem?
Please help me

King regards Jasper

[Naj ✝︎]

quote:Originally posted by Jasper82

Thanks for al the comments, I have been working on the car yesterday.
An checked al the wiring (like you guys told me) but the car still don't start. Is maybe the transistorized ignition the problem?
Please help me

King regards Jasper

Try testing it:

http://www.sl113.org/forums/uploaded/jeffc280sl/15-20B.pdf

naj

68 280SL

[Desertpagoda]

Buy a new electrical ignition switch. These fail (the crimps loosen) often on many models of MB not just 113. They have internal connectors that can be incorrectly assembled in several ways. New switches are cheap and easy to find.

kb

[Jasper82]

Thanks Naj,

But I have already test it, and it works fine.

Jasper

[Naj ✝︎]

quote:Originally posted by Jasper82



But I have already test it, and it works fine.

Jasper

Check the green wire to the distributor.
It is co-axial, the outer one is grounded but the inner one is insulated and should not be grounded!!!

naj

68 280SL

[al_lieffring]

quote:Originally posted by Jasper82

I am jasper from Holland. An have a problem with my sl please help me with following. My ignition switch was fall a part, and i fixed that with (i think)the right wiring schedule. But now the car won't start.
The spark plug only sparks once when turn of the ignition key. Do's any one now this problem. The car has transistorized ignition!

Kind Regards Jasper

Jasper

Before you spend a big bunch of Euros on a new ignition control box, check the two ballast resistors. I don't remember witch of the two it is but when one fails the ignition will spark when the starter is cranking but stops when the key is in the run position.

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