Brain Problems
 

No juice to fuel pump or aux. air regulator on '71 injected 1.7 914. Relay that powers brain & aux. air regulator getting juice but no ground. Ground wire from relay board to brain pin 19 has good continiuity. Spare brain does same thing. Only discovered the problem while trying to T/S aux. air regulator. Fuel pump now relocated and powered from different circuit. Car runs fine, just no juice to heat up the aux. air regulator. Help.

I would suspect that you have a wiring harness problem. The older wire harnesses get heated up and brittle when they sit in the engine compartment for many years. Take the harness out and check the continuity with a multimeter (available from Radio Shack, etc.) This will tell you if you have a bad harness.

We have good used harnesses in stock if you need one.

Hope this helps,

Wayne

Stuff to check:

Continuity inside the relay board. Check that you've got +12V at the power supply socket for the fuel pump relay, and that you've got connectivity from the wiring harness plug-in spots (sorry, this is pre-caffiene this AM) to the relay socket pins.

Ground connections. Check the big multiple ground point at the rear of the case. The ECU gets its ground there, as do the injectors.

Continuity of the ground wires from the ECU to that ground point.

That's all of the top of my head.

--DD