Gremlins

[Geoff1200]

My 73 Cuda 340 has some electrical issues I have yet to resolve. Car runs fine but aftermarket volt guage (and my digital multimeter) show voltage all over the scale 10-14v. When it does this the car runs rough understandably. I've replaced the Alt. and Regulator, checked connections, grounds and even the fire wall plugs. What am I overlooking?

Previous owner replaced the wiring harness with a Yearone piece...

 

[Tunis]

Where do you measure the 10-14 volts? At the battery or at the alternator?
If you measure 10 volts over the battery, I would replace that!

 

[Geoff1200]

Battery passed load test...

 

[hpjunke]

geoff1200 does it have and ignition box with a non points distributor ? my 70 roadrunner would run like crap die out and restart everytime so i changed the box and it now runs fine..

 

[Geoff1200]

It has the oem electronic, car is stock except for headers.

 

[Tunis]

Take the multi meter and measure the resistance from battery plus to alternator output stud (with the negative battery side disconnected). It should have a very low resistance like 0.05 ohms. Also measure the resistance on the wires going from regulator to alternator. Corroded terminals will increase the resistance and can together with some bumps in the road etc. cause some weird effects.

Make sure you have good grounds on alternator and regulator.

Per

 

[challenger440]

Would have to be extremely corroded to cause such a big drop but good point to double check it nonetheless. False positives can keep you chasing your tail so wouldnt hesitate to double check basics. Battery (what voltage does it read when not charging BTW?), connections, output from alt. and wiring. Maybe check wiring with an ameter to be certain it is not the issue.

 

[Geoff1200]

Thanks for the input, I'm electrically challenged...