I have a 76 W100 with a 318, I had my timing set at 12deg. BTDC and I was getting some knocking from the motor. Tonight I set it at about 5 deg. BTDC, seems to run ok but now my alt gauge wants to stay on charging side of the gauge. The higher the rpms, the more it goes to the charge side. It will do this for a while then go back to normal in the middle of the gauge, it has done this twice now, what is going on?

 

Im thinking ground wire somewhere.

 

chrysler alternator amp gauges are known to be fiakey. i have seen the posts wrapped with wire to take the gauge out of the system. if i did that i would put a volt meter on it. from what i have seen volt meters do tell you what you need to know

 

That usually indicates it is charging the battery back up. You never saw that before? Maybe the gauge just started working again. I wouldnt be to concerned if it returns to the normal range after a few minutes. If you turn the headlights on it should go towards the charging side of the gauge too.

 

Battery could be down, as said above, might just not have charged up yet, or...........might be a problem.

Get yourself a multimeter, which you should already have. If not, parts stores, Radio Shack, or Sears

With the engine running at a good fast idle, check charging voltage right at the battery posts. Make sure the engine is running fast enough to charge

At the bottom and top end, should be no lower than 13.5, no higher than 14.5

Optimum, with engine (regulator) warm, is 13.8--14.2

Common problems are poor ground between regulator and battery

Also common is poor connections in the bulkhead connector, the ignition switch connector, bad ignition switch, or even poor connections at the ammeter cause over charging.

Worst case, the regulator could be bad

 

I put a meter on it when it was doing it today, 13.5 or so, so it is good. When it is doing this my radio will not play, but when I let off the gas when coming to a stop sign the radio plays again. The gauge has never done this before, it has moved a little but never all the way over.

 

Frustrating. With a battery reading of 13.5, that seems fine, but the radio quitting indicates "problems."

Try this:

Check running / charging battery voltage with the engine warm and at a good fast RPM to simulate "low to medium cruise"

If it's again about 13.5--14.2 (and this is with the ammeter hard over?)

then check voltage CAREFULLY at the alternator output stud. If the voltage at the alternator is more than 1 volt or so HIGHER, then you have a bad connection in the charging line, most likely the bulkhead connector, ammeter connections, or a bad ammeter. in RARE cases this could be the welded "in harness" splice

It MIGHT also be a battery with one cell going bad. Find someone with a carbon pile load tester and have the battery tested. Do this after being certain that the battery is not simply "dead" or down.

 

I put a new voltage regulator in and all seems good. I have a strong 14 at the battery now.