Help with electrical? diagnostic

[sputnik 440]

Before I just go and buy a bunch of electrical components I may not need, I would like to get some advise. I have never had a voltage regulator go bad, so I am not sure I am on the right track. I know I need a new battery, but I don't believe this is my problem. The alternator is right in line with the regulators. Sure hope it is not the MSD 6AL. Story......I keep the battery on charge and it works fine unless I don't keep it on charge for 10 days or so. The battery was charged, the 440 started right up. I drove it 20 miles to town and made several stops. Came out and the '67 Satellite started after each stop. Last stop it struggled to start and I noticed the battery was not turning the engine over like it should. It started, I drove it out of a parking lot and it stalled while making the turn onto the road. Would not start and the battery went almost dead. I recall when I was driving into town that I looked at my gauges and noticed the dash gauge showed the charge a bit high. I looked at the instrument gauges below the dash and saw that the volt gauge was pegged out at 16. I thought it was strange, but just didn't think much of it (bad wire? gauge?). I brought the car home on a flat bed and charged up the battery. The engine will crank, but no fire. This tells me it is not the alternator, I think. Could my whole problem be the voltage regulator? Wouldn't it account for the over charging on the gauge? Long story, but I wanted to make sure someone out there had all the facts. Thanks for your help. Oh, what about the coil?

 

[oldbee]

Replace the battery!!! If it won’t hold a charge for a week or so you probably have a bad cell in it. Then check back. A bad cell will affect charging also.

 

[PurpleBeeper]

Wow, you may have more than one problem.
1. Cranks, but doesn't fire --> first check that you have spark at the plug (ground an extra plug in any plug wire & have a friend crank it over). If no spark, keep backing up the line. Distributor/cap/rotor test --> unplug double connector at distributor, disconnect center coil wire on distributor & put a small phillips screwdriver inside it & place the screwdriver about 1/8" from a good ground, turn key to on & temporarily ground the distributor plug (harness side/exposed terminal) & every time you touch it to ground a spark should jump at the screwdriver. if no spark, keep backing up to blue wire out of bulkhead disconnect --> 12V with key on?
2. Voltage regulator --> I'd just change it for $15, what the heck? Also, check ground at the base + where the base bolts to the firewall (scratch off some paint/sand)
3. Once it's running, check charging system + battery. Full charged, put a meter across the +/- posts of the battery and it should read just a bit over 12V. Start the motor and it should read almost 14.5 volts while running. If still 12V while running, carefully put a flathead screwdriver behind the center "bearing post" of alternator (about the size of a nickel & flat/smooth). If the alternator is charging, that "nickel" should be magnetic (test with non-magnetic screwdriver). If not, then check for 12V at the field wire(s) going to the alternator (don't need to in-hook them).
4. Check all your grounds....- of battery, block, chassis & clean to bare metal behind them.
5. EDIT --> as bee mentions....at least have the battery tested for free at a parts store.

Hope this helps

 

[Xp29h]

Remember MSD likes voltage! If bad battery, regulator etc.. voltage will be low and possibly frying msd. Start with good battery and go from there as mentioned above. Good luck

 

[oldbee]

+1 on purple’s post #3, forgot about that.

 

[Wietse]

If the gauge is correct and the voltage really reaches 16V then your regulator is a goner.
Due to that you might have boiled your battery.
Cranking but not starting could indicate the MSD ignition is toast as well, or as Xp29h mentioned it does not get enough juice anymore and fails to give a good spark.

First i would get a new voltage regulator and battery and try to start again.
If it does fire up check the voltage across the battery terminals, if at idle still measures 12 volt or so, rev the engine up a bit and monitor voltage.
When running at higher rpm you should see max. 14-14.5V on the battery.

 

[Ranger16]

When I first bought my '69 Road Runner 4 years ago, it did not have any aftermarket gauges. I added a set over the winter and found it charging at 16 (maybe higher as it was pegged). I can't speak for the MSD, but I was told that the Mopar Performance ECU does not like over charging. Sure enough, it failed after a few intermittent stalls. I replaced the factory mechanical regulator with a Wells VR706 as well as the ECU. Problem solved.

That said, my 1 year old battery would not hold a charge. Replaced it yesterday under warranty.

 

[skingjack]

I note that there are many suggestions to replace the voltage regulator; Any reputable brand/model recommendations or will any part store replacements be satisfactory?

 

[Wietse]

See below, think this fits yours as well. (not sure what model/year we are talking here)
All old regulators were operated mechanically, these new ones are electronic and are more accurate and reliable.
Just do a search for your application and you will find it.

https://www.summitracing.com/int/parts/smp-vr101/overview/year/1969/make/dodge/model/coronet

 

[oldbee]

Wells VR706. Get away from the old mechanical regulator.

 

[Gargemel78]

I would take a voltmeter and check the battery with the car started. See how much voltage there actually is. If there’s more then roughly 14 volts. I would replace regulator, it’s overcharging the battery. Go to Oreilleys and have the battery load tested overcharging it might have made it go bad. Just make sure after all said and done there is close to 14 volts at the battery with the car running. Turn the headlight on bright and make sure the voltage drops and comes back up to almost 14 volts

 

[skingjack]

Unfortunately no O'reillys in Canada- will try another local outfit that offers battery load testing (hopefully complimentary). Speaking of the battery, when the vehicle is running is fails to read greater than 12.6. I suspect the alternator may be the issue rather than VR. Will perform the tests Purple has suggested earlier in point #3 of this thread.