Why doesn't my car run?!?! HELP, Electrical problems suck.... Options

[ojai914]

OK, I just picked up a '70 1.7L and it didn't run. I narrowed it down to electrical problems, and I just replaced the distributer cap and rotor, charged the battery and got it tested, replaced the spark plug wires and coil, and made sure everything looked good. However it still doesn't work.

I tried sparking the starter motor to make it run, and even that didn't get it to turn over.

Now the really weird thing is that yesterday, I got it to turn over first try by just turning the key but now it won't do that. Does anyone have suggestions or pointers of things I can look at? Help a n00b out, please.

Thanks,
Mark

[Spoke]

This is easy for me to say since I'm an EE, get yourself a multimeter (ohm-volt-amp) and a schematic for your car, and maybe a friend familiar with the 914 or with electronics/schematics. Debugging electrical issues without a multimeter and schematic is impossible. A schematic is nothing more than a map of your car's electrical system. Just like you would find your way with a driving map, use the schematic to follow the path of electricity from the battery to the components in your car. A good schematic will also include wire colors which help.

Use the multimeter to test for electricity and don't assume that wires are perfect connections. I recently debugged the heater motor in my 74 just to find that a wire that was visibly grounded wire wasn't grounded. The connector had oxidized and was not making electrical contact.

With the multimeter on the ohms setting and key off, check resistance between the chassis metal (not paint) and the engine/tranny. Should see 0 ohms. If not, check the grounding straps. Same thing with the battery ground cable to chassis. A wire may look physically connected and can be electrically disconnected because of oxidation and corrosion.

Good luck,
Spoke