Altenator

[bw396ss]

HI all,
Need some advice. My 68 has a strange issue. When I fire up the engine the altenator light comes on. I have a volt meter on it as well at is registers approximately 13 volts. When I "goose" the accelerator, the light goes off. back at idel the voltage is now about 13.5 to 14 and the light remains off and never comes back on agin until the next starting cycle. I have changed the voltage regulator and checked all the wiring, all is well. I changed the brushes in the altenator and had a load check done on it and everything checks out OK.
What am I missing?
Any thoughts?
Thanks so much.

[Hank70SS]

I assume the idle RPM when the light is on is the same as the idle RPM after you 'goose' it and the light stays off.

Start checking grounds. Battery to chassis, the small pigtail off the negative battery cable. Voltage regulator to rad core support. Forward light harness grounds to rad core support. When I put my car together I didn't have all the grounds on the core support hooked up and the light would glow. Hooked them all up and light went out.

What kind of voltage regulator did you put in? The Wells VR715 is a good solid state regulator for under $20. Same size and direct replacement for the old mechanical regulator. AutoZone sells them.

You should have a little over 14v unless the engine is at idle and you have a lot of accessories on and the alt can't keep up.

[dbradley]

I second the "Wells" regulator but "if" you're using an OEM type be SURE that the case is grounded to the same potential as the alternator. Check resistance from the case of regulator to case of alternator.... should be zero or very near zero ohms. One of the regulator mounting screws has a jumper strap to provide ground of the case. A lot of times the radiator surround will not be well grounded to the chassis or engine and this prevents the 'signal' voltage to trigger the alternator with enough voltage to start the charging process. Increasing the rpms will override the bad ground condition and 'start' the alternator (till next time). Also be certain that all the pins/contacts are clean, with no frayed wires.

[tunes]

Hi Bill,

Just give that '68 to me and you won't have to worry about it any more. :D

[Hank70SS]

What dbradley said. You said you already changed the voltage reg so I didn't mention it but the ground from the voltage reg case to the core support is important.

[bw396ss]

Thanks all for your input. I will check the ground potentials as I can't really say I did that completely. Thanks very much.

To: "1969 L78 Chevelle" You already have too many toys.

Regards all,