'74 Duster exploded battery
 

Hello everyone,


I have a some electrical problems with my Duster. For 2 weeks ago, my battery exploded! It turns out that the voltage regulator was defect, so i replaced it for a new one. And of course a new battery. Still, the problem is not solved. Therefore i also mount a new alternator. It makes a little difference.


Now, when i drive about 30 (or slower) mls an hour it runs perfect. When i drive faster, the alternater goes whistling because it rotates to fast. At that point, when i measure the battery, it says 17,8 volts or higher instead of the 14,4 volts.


Is there anyone familiar with this problem?


New parts (among other parts): alternator, voltage regulator, battery. Same problem.
Car: '74 Duster 340 stroker (Original 318)


Sorry for my english but i'm from Europe!


Greetz and thanks, Michael.

Important to understand how this works. These are easy systems to diagnose Here's a simplified diagram

http://www.mymopar.com/downloads/Dua...tor_Wiring.jpg

The two field connections on the alternator are interchangeable. IE the blue and green can be switched.

Your first task (easy) is to make certain the green connected brush is not grounded. Simply disconnect the green and run the engine a bit. It should NOT charge. If it does, that brush holder is GROUNED

Second task is to make absolutely certain the voltage regulator is GROUNDED. Clean the firewall and rear of the VR flange, and mount TIGHT with star lock washers.

Then CHECK it with your meter. To do that, run the engine at a fast idle to simulate low/ med cruise speed. Stick one probe of your multimeter directly onto the battery GROUND post. Stick the other probe onto the VR mounting flange. "Stick hard" to stab through paint, rust. What you are hoping is a VERY low reading, nor more than .2V (2 tenths) of a volt or best of all, ZERO

===============================

Next, check the voltage drop to the VR. This is a bit more difficult because you cannot directly probe the VR connector. your "ignition run" (IGN1) voltage comes through the firewall, and branches off to feed the ignition, alternator field (blue) and the VR (blue). So determine which connector on the ignition ballast is "ignition." Turn the key to "run" engine stopped. and measure both / all 4 terminals. The one which is highest voltage is what you want

Leave your meter connected to that terminal. Move the ground probe and stab it into the battery POSitive post. As with the ground reading, you are hoping for a VERY low reading, no more than .2--.3V (no more than 3/10 of one volt). If there is MORE voltage, you have voltage drop in the harness

Your numba whone suspects are the bulkhead connector, the ammeter connections, the ignition switch connector, and the ignition switch.

IF this reading is low, no more than .3V change the VR. Yeh. I know. You did. "New" does not mean "functional."

Also, inspect the VR connector carefully for corrosion. "Work" it in/ out several times to scrub the terminals and to "feel" for tightness

Also, you may have another crap voltage regulator! I have gone through this several times with low priced units. Best to buy the pricier piece, and if possible get a mopar regulator!

where would anyone get a new mopar regulator?

Mopar Performance Parts Catalog pg. 108

IGNITION AND ELECTRONICS
VOLTAGE REGULATORS
A. Voltage Regulators
For restoration or repair, Mopar offers this factory reissue of the Voltage
Regulator as used on muscle cars of the early 1970s. The regulator is black with
the original Mopar part number imprinted in yellow. Contains modern electronics.
1 77R06285 Voltage Regulator, 1970, Restoration
1 77R06286 Voltage Regulator, 1971, Restoration
1 P4529794 Voltage Regulator, Muscle Car, O. E

You could get a junk yard one. Frankly the failure rate on HIGH quality original OEM or older "parts store" ones are very very low. I think Ma used these on pickups and vans up until they went MPFI, the regulator then "in the computer."

Or buy the best one that Standard / Echlin/ NAPA sells

I Also think you have gotten a bad regulator.....

But also make sure you have a good ground when mounting the regulator and also make sure you have a good ground from the engine to the firewall....

Just do not use the Blue racing regulator.... That one puts out continuous high voltage....

Keep us posted....

I have agree with Bob on checking for good clean grounding everywhere. Anytime you get a unexplainable electrical problem and the usual repairs do not correct it, look at the grounds.

Thanks for the replies, guys!


The new parts are all Original mopar parts, so i'll go and check on the grounding.
I'll be back!

the restoration regulators above are junk.

Ok, i've replaced the groundcables and the wiringharness and the car is running! The exact problem has not been found.... Let's hope for the best.
Thanks for the help.

So is the voltage "normal" at nominal 14?

That's correct!!

So its been over a year without problems but now its back!
This morning both the headlights went out while driving the highway. The voltagemeter indicated maximum to the right. So i think the regulator has broken again! This is the third one in a year. I've replaced almost everything in terms of the electrical system.
How is this possible?
Anyone a suggestion?
Thanks!

I would be looking for a short.

Been There Done That! Crap offshore regulators!

OK Drag pack how does it happen? Calling you out.

Lol. I have been on the receiving end of three of these offshore pieces of crap. Probably 3 in a bit over a year or so.

About $15 at the local parts store.

Radio would buzz, wipers were intermittent, lights would dim, always showed a bit of a charge on amp gauge(abnormal). Then on the last one, the battery blew up(blew the side right out of it), and it was the 750 ca type battery in our 89 Ram 250 diesel. A real mess to say the least ( a lot of baking soda and water to clean it all up).

Bought the $40 regulator from the same parts store and all is well for several years now.

Make sure the mounting surface is good and clean for the regulator... Make sure you have a good grounding strap from the engine to the body... I like to add a wire from the ground of the regulator body to the engine just for good measure.

I also have had to get a couple of those cheep'o regulators replaced...

Also might want to read the infomation on the MAD Electrical for alternator issues to help if all else fails...

Just my 2 cent....:)

I think i've solved the problem.
Thanks to this link.

http://www.madelectrical.com/electri...p-gauges.shtml


Thanks everyone!

Let us know for sure.... :)