why would only one set of points spark on my dual point system

[rbauwen]

Hello

Does anyone know why only one set of points of my dual points 73 240Z automatic is sparking? Also, is it possible to try and get the engine running by using gas out of a bottle, since the fuel tank is being reconditioned? Thanks

[5thhorsemann]

Set the fuel bottle up like an I.V. and hang it above the motor 2 or 3 feet.

As for the points, if one is oxidized alot more than the other, the full load will go through the clean set.

[Arne]

Factory 240Z dual points (only in automatic cars) are not a performance deal, they are designed to only use one set at a time, and switch between the two sets to vary the timing for emissions.

[EScanlon]

Arne is spot on, and the other set come into play only after certain operating temperatures have been met.

There's a Thermo Relay mounted just below the Coil that connects to the AT Thermo Switch and the distributor.

The concept of corrosion on the points have nothing to do with either set of the points, since the relay switches the ground for the points and therefore disconnects the initial set of points. i.e. both points do NOT operate at the same time.

That bit of mis-information may be true on other vehicles makes but does NOT apply to the AT 240 Z.

E

[5thhorsemann]

Never saw a set of dual points on a Z, so sorry for speaking out of my league, I only had experience with performance DP distributors on American cars.