Alternator questions

[project 911]

I'm about at the end of my rope. I've been trying to get my car running right and diagnose problems for a week now, and instead of getting better, more things keep going wrong.

I,ve got a 70T 2.2 with carbs. Original alternator with external regulator. I replaced the reg a couple months ago with a solid state version from NAPA and my volt meter has been more steady than with the old reg. Today while working on the car a glanced at my volt meter and it was acting like a tach. If I reved the engine the volt meter went up to 16 or more volts! I put in one of my old regs and the meter reads fine now.

My question is, can an alternator that is going bad burn out a regulator? I've also burned out two RPM transducer lately too, but I figured that was from me screwing around trying to get my tach working with my MSD box. The problem I've been having all week is the engine stumbling under load (only) when taking off in 1st at lower RPM's. Doesn't do it at idle or when reving, or once you get the car up to speed.

Should any of this be telling me something? I've checked plugs, wires, cap, rotor, carbs... I'm running out of ideas.

[FrayAdjacent911]

I would be thinking regulator. Is the voltage too low at idle?

I'm sure some people with much more knowledge will jump in and help out here. It's just amazing how much knowledge there is here. I'm still learning every time I come here!

BTW, you said 70T, and your sig says 71T? They're pretty much the same anyway.

[RoninLB]

I'm not a pro but I'd do an alternator AC ripple test.

also bad battery connections, alt connections, etc can cause charging problems.

A few pelicanheads have complained about solid state external regulators going bad.

[Early_S_Man]

Steve,

Generally speaking, a failing alternator can't 'hurt' a regulator ... because everything that goes wrong with an alternator causes lower output Voltage or current. Failure of a relatively new regulator is a quality control or infant mortality issue!

Your old regulator should be kept, because even if it is 'off' a bit the contacts can be cleaned, and it can be adjusted to work like new when it left the factory! There is a myth that many misinformed people on this board espouse that many old electrical part just 'wear out' and must be replaced, but that is PURE BS!

Just like CDI units, RPM Transducers, tachometers, and MFI pumps ... old alternators and regulators can be rebuilt and restored to like-new performance!

One very important thing that can cause regulators to fail is bad grounds ... so be sure to clean the trans-to-body, battery, alternator, and electrical panel [behind CDI unit] ground straps!

[project 911]

Thanks Warren,

That helps knowing that a failing alternator wouldn't create higher voltages. I'm pretty good about having clean grounds, but I'll go over them to be sure. I posted a few days ago about rebuilding my transducer, but didn't get much specific feedback, and hoped to just delete the whole enrichment solenoid thing.
I guess I figured when I got the solid-state voltage regulator that it would hold up better being sealed form moisture, but I guess not.
You mentioned that you can adjust the original regs? I've cleaned contacts in them, but never knew about adjusting them.

Matt- Yup, the car is a 71 but the engine in a 70.