No Fire to Plugs

[Harry]

I was just trying to start my rebuilt 230SL and it would not ht.  I put an inductive timing light on twp or three plug wires and got no indication that I had fire.  I marked everything carefully before taking it apart and reassembled accordingly but something obviously isn't right.  I've looked at the wiring diagram and in the tech manual but I notice there is a small relay on the fender skirt almost above the sub-frame mount that I don't find on the diagram.  But it is in the loop for the coil/ballast resistor.  Does anyone know what this relay is for?

Harry

[Harry]

Here is a photo of the relay.

[Benz Dr.]

That's a typical relay used on our cars but it's not one that I've seen mounted in that position. 

I don't think it would have much to do with a no spark condition. If you have an original distributor check that the points are opening and that you have power at the moving part of the points. I've seen where the post going through the distributor body can short to ground and cut off voltage to the points.

[ja17]

If you put a piece of thin cardboard between the ignition contacts (points) and turn on the ignition, you should be able to follow + power from the coil to the distributor and to the one side of the contact (points). As Dan suggests the wire going into the distributor often shorts out after the insulator sleeve disintegrates from age.

[Harry]

Well - turns out the ground wire at the distributor was broken, but not obvious.  After two years of engine rebuild, repaint of engine compartment, rebuild of front end (including subframe mounts), reinstall of A/C with new compressor, and what seems like a lot more - she ran super!!!  Can’t wait to go for a long overdue ride!
Thanks to the Forum for all of the ready support!
Harry

[hansr433]

Always great info on this forum and glad this was resolved.

Harry, I do love a tidy engine bay.  Very nicely done.