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Posted by: aoor0708 Feb 23 2020, 03:07 AM

Good morning.
Am a bit confused about the function of the trigger points in a 914 - 1.7 liter - 1972
Thought their only function was (is) to prevent engine overrun at more than 5700 rpm.
This confusion comes from the fact that on the market I can buy Delcos without those points and are being advertised as suitable for a 914...?
Anybody can shine light on this matter ?
Thank you

Posted by: Tbrown4x4 Feb 23 2020, 05:15 AM

I'm up later than usual, but here is a partial answer:

If you have the original D-jet distributor, the are actually two separate sets of points. Under the ignition rotor is the set that controls spark, and lower, inside the distributor, is a pair that the ECM uses to fire the injectors. (Look for a 4 wire connector on the distributor body.)

The 5700 RPM cut-out you describe is controlled by the original rotor, if it hasn't been replaced by a "normal" rotor. The originals have a spring loaded contact that grounds the ignition over 5700 RPM.
http://www.allzim.com/store/var/images/product/300.300//home/newzim/public_html/store/images/product/inherited/4940.jpeg

Any distributor being used on a D-Jet, fuel injected engine, has to have the lower trigger points or it will not run. For example: the fully electronic 123ignition distributor has a D-jet version that provides the ECM with a "fake" signal so it will fire the injectors.

If you have carburetors, an L-jet or an aftermarket FI system, the lower trigger points are not needed. BTW, a member here was making a tool to set the proper gap of these trigger points. I don't know if new points are available or not.(too late to look it up. )

Posted by: BeatNavy Feb 23 2020, 06:40 AM

Yup, I think you are confusing rev limiting rotor with fuel injection trigger points. I believe the trigger point connection is three wires, IIRC (one ground, and one to fire each pair of injectors).

The Delcos distributor is probably intended for carbureted cars. I don't think trigger points are available to purchase new. The member that sells the adjustment tool is nordfisch (from Germany).

Posted by: Spoke Feb 23 2020, 09:08 AM

Does your car have fuel injection? The FI system uses the contacts (trigger points) to fire the injectors and turn the fuel pump on. If you have carbs then the contacts aren't used.

The trigger contacts in the distributor are the only way the FI ECU knows the engine is rotating thus turns the fuel pump on (if contacts are open/closing) and turns the fuel pump off when the contacts are not transitioning.

Posted by: aoor0708 Mar 8 2020, 04:19 AM

QUOTE(Spoke @ Feb 23 2020, 09:08 AM)