So... what exactly are trigger points, and how could I try refurbishing them?

[Mölyapina]

So what do these (does this) do, exactly? Is this just "a" trigger point? Does a car get one per cylinder, or is this all that one needs? How do I go about refurbishing these?

Sorry for the ignorance, I'm a diesel guy...

[Zulfiqar]

they look like two contact breaker (CB points) - if they are they break the ground for the ignition coil causing it to dump a spark for a plug

[pmckechnie]

If they are from a mid '70s Mercedes they could be trigger points for the fuel injection system.

Paul

[Mölyapina]

Originally Posted by pmckechnie

If they are from a mid '70s Mercedes they could be trigger points for the fuel injection system.

Paul

They are from a 1973 450SEL, I believe... martz0r's 'Benz.

[Jay Gibbs]

Originally Posted by pmckechnie

If they are from a mid '70s Mercedes they could be trigger points for the fuel injection system.

Paul

They are used by the Bosch D-Jet fuel injection system to time the firing of the injectors 4 at a time. Typical failure mode is sporadically you'll only have 4 of 8 injectors firing and the car will run like sh**! Here are a set for sale on e-bay by the MBZ Classic Center. At this price, they are roughly half of what I paid just a couple years ago...

Mercedes Benz Classic Trigger Points 3 5 V8 Engines | eBay

[hookedon210s]

Actually there are 4 points on the V8 engine trigger points set, each of which controls 2 injectors. Mark

[Mölyapina]

Originally Posted by hookedon210s

Actually there are 4 points on the V8 engine trigger points set, each of which controls 2 injectors. Mark

...so I have one of four?

[hookedon210s]

No, there is one trigger point "assembly" which includes 4 sets of points, 2 located on the top and 2 located on the bottom (in the picture posted previously you can see 2 sets of points on top and the rubbing blocks for the other 2 sets of points on the bottom). Mark

[Jay Gibbs]

Originally Posted by hookedon210s

Actually there are 4 points on the V8 engine trigger points set, each of which controls 2 injectors. Mark

You are right. My particular failure involved 2 of the points not firing, so I had 4 of 8 injectors not working.

J.G.

[Mölyapina]

Sounds good. I just found a page talking about the D-Jetronic system, and also ordered some manuals. Thank you all!

[berfinroy]

They are points much like distributor points, and therefore should respond to the same kind of contact point cleanup procedures to restore electrical contact integrity. Once cleaned up, they should faithfully make electrical contact for some time as these points transmit low voltage. HOWEVER, there are many threads herein concerning the contamination of these points by oil oozing up the distributor shaft. See: Dirty Harry's May 2011 post "Djet dist." for example. This issue has to be rectified to keep the car running well for extended periods of time.

[dirtyharry]

yep those look like revised R107 trigger points but missing plastic covers... one interesting note is that in addition to the plastic covers the newer style also have grease catcher tabs on top and bottom sets.... they are open for a set amount of time and then closed, signaling the starting and stopping of injector pulses but not controlling duration. easiest way to get the vehicle to run is to gap them all with a feeler gauge to the same amount.

[werminghausen]

the points almost never go bad, only the plastic lid that slides on the cam is wearing and therefore the points do not open enough at one point an give the wrong signal. You can correct the closing and opening angle if you are bending both lower and upper arm in order to compensate for the wear.
Points also might just be 'dirty'. So clean them and test (opening and closing angles) before you start bending parts.
Her is a link to m-100 forum
http://www.peachparts.com/shopforum/vintage-mercedes/264678-testing-trigger-points-2.html