Help :) 75 2.0/FI runs perfectly until the car is warm and under electrical load, Advice? Options

[Jett]

Our 75 2.0/FI car has completed a two year restoration that included an engine and transmission rebuild, along with rebuilding or replacing all FI components.

The car runs perfectly all the time until it has been running with electrical load for 30 min (radio w/Bluetooth, rear fan) and then I turn on the headlights. The car immediately starts to sputter and will die unless the lights are turned off, which puts the car back to perfect.

We initially thought that it was a bad ground in the headlight circuit, but cleaned and verified, no red flags there.

Is it possible that the mounting plate for the regulator has a bad connection? I think it is original to the car.

Any help would be greatly appreciated as last week I had no lights coming back from the first cruise.

Thanks

[Van B]

Have you measured voltage under these different load conditions?

[Superhawk996]

Have you measured voltage under these different load conditions?

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Start with the basics as suggested above.

The headlamps are the largest electrical load on a stock 914.

Sounds like you're getting low battery voltage and when you apply the large headlamp load it collapses the battery voltage. Probably to the point that the coil or the ECU no longer have adequate voltage supply causing the mis-fire.

Quickest fix will be testing with DMM in a methodical manner.