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The 5700 RPM cut-out you describe is controlled by the original rotor, if it hasn't been replaced by a "normal" rotor.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/pro...rited/4940.jpegAny 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.
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