I have a 71 340 4spd duster and everytime I get on the gas I blow lightbulbs. I have replaced my voltage regulator and I had my altenator tested and it passed. Does anyone else have any ideas of what is causing this because this has me stumped. Thankyou
you have a missing ground wire... or your alternator or wiring is allowing the alternator to max charge..got a digital volt meter????? this test takes less than a minute...set it to 20 volt dc scale... start the engine... turn on the head lights...touch one probe to the negative battery POST... touch the other to the engine block... less than 0.05 volts is good..touch one probe to the negative battery post... touch the other to the body.... less than 0.02 volts is good.touch one probe to the engine block.. touch the other to the body... less than 0.02 volts is good..then...touch one to the negative battery and the other to the positive battery post.. you should get just over 14.1 volts.. have someone bring the rpms up... you should NOT get over 14.5 volts...which voltage regulator do you have???? mechanical or electronic... mechanical has terminals on each end.. electronic has a plug on the face...which alternator do you have??? one with a single quick connect terminal... or one with two quick connector terminals..
Thanks ill try that when i get home. it is an electronic voltage regulator and my alt. has 2 quick connectors. Ill tell u my results sometime today
ok i tested it and my negative to body and block was fine but at an idle I was reading 15.1 volts avg and at bout 3000 rpms I was reading 15.75 volts. Another thing I forgot to add is that my battery has leaked a littlebit of acid. does this give you any ideas?
thats a lot of voltage... and i can understand why your battery is boiling over...can you measure the voltage on the center terminal of the voltage regulator while the car is running????and is the voltage regulator mounted tight... the body of the voltage regulator has to be grounded...i have run into under charging and over charging on other mopars... after swapping in a new voltage regulator... and it still happens... i have added a relay to power the center terminal of the voltage regulator ... so it gets correct battery voltage...the old wire to the center terminal.. to pin 85 ground the wire going to Pin 86pin 30 is a wire from the stud on the starter relay.. with a 20 amp fuse... just to be sure...pin 87A... goes to the center wire of the voltage regulator..how the alternator and voltage regulator work... with an electronic regulator.. there is switched ignition power to one of the brushes.. the other is connected to the side connector on the regulator.. the voltage regulators center terminal gets switched power... it looks at that voltage. and pulses ground to the alternator.. this pulsed ground completes the circuit to the spinning rotor.. since longer pulses create a larger spinning magnetic field... this magnetic field moving through the stator windings creates voltage in them.. positive diodes allow any AC voltage above 0 to come out the positive post on the back of the alternator... negative diodes allow any AC voltage below 0 volts to pass through to the case of the alternator.. into the block and to the ground wire.... you have to remember... ac voltage is measured from the top of the seine wave to the bottom of seine wave.. so 14 volts has 7 volts positive.. and 7 volts negative... what i am worried about is if your alternator or part of the wiring is shorted to ground.. this would make it max charge.. this is why i want you to unplug the rubber connector at the voltage regulator.. see if it is still overcharging.. .. it should not be charging at all....i looked over at the wiring diagram... seems the dark blue wire that powers the voltage regulator also powers the one of the side connectors of the alternator.. several other things under the hood... up to the instrument cluster... starts at the ignition switch.. passes through the bulkhead connectors also... it shows as a dark blue with a TR.. what ever that is.. probably a dash along the wire insulation.. if there is resistance lowering the voltage on this wire.. it will cause the voltage regulator to call for a higher charge voltage... you might really want to check for resistance at the bulk head connector... or install the sure fire fix... a relay.. to isolate it from the rest of the circuit.. it all depends on how original you want... but this relay will sure cure your problem..
so what kind and size of relay should I install? Am I gonna run another power wire from the battery to isolate it? and finally is it gonna be on this blue wire connecting to the alt. and the regulator? thankyou
you can install any of the little black cube relays... they are available at most radio or alarm shops.. i will post some links... these are available locally in most cases...here is the relayhttp://www.allelectronics.com/make-a-store/item/RLY-351/12V-SPDT-30-AMP-AUTOMOTIVE-RELAY/-/1.htmlhere is the socket for the relay.....http://www.allelectronics.com/make-a-store/item/SRLY-2/SOCKET-FOR-AUTOMOTIVE-RELAY/-/1.htmlclip the wire to the center terminal several inches back from the rubber connector... strip both ends...connect the wire to the center terminal of the voltage regulator to pin 87A on the relay.. (which ever wire on the pigtail connects to it..) connect the car side of the wire that you cut.. to pin 85... which ever wire..connect the wire on the pigtail that goes to pin 86 to ground... connect the wire that connects to pin 30 on the relay to the threaded stud on the starter relay.. so.. you will also need crimp terminals... pink and blue... at least 2 of each..a number 12 pink or blue ring terminal for the pittail on pin 86 with a screw to hold the relay in place..most of the time.. the starter relay is farther away than the pigtail leads will reach.. and you will need a 5/16 ring terminal for that.. a short section of wire to make it reach... as for the blue wire to the alternator... it will work just fine...this relay will only control the output voltage of the alternator.. i along with others i am sure would like you to find the resistance in the circuit... if its in the bulkhead connector.. the ignition switch, or something else on the circuit partly shorted and dragging the voltage down on that circuit..((( when the voltage regulator sees reduced voltage on the center wire... it thinks the charging system is not at the proper charging voltage, so it raises the charging voltage until it sees the proper voltage on the center wire...)))
A couple of times I have found a broken wire in the reg plug for the center terminal. It breakes inside and can not be seen. Sometimes it will make contact and sometimes it will not, so testing for it can be difficult. You may try replacing the reg plug. They are inexpensive and easy to replace.
I'm not sure how to test for resistance. But I put the relay in lineof the blue wire and I am still reading 16 to17 volts wheni rev it a little bit. It is a 30 amp relay. Would this make me difference?
thats strange....what happens .. when you unplug the voltage regulator ..... what kind of voltage do you get when you rev the motor...it sounds like the alternator is full fielding.. putting out max current and voltage... if the brush holder on the side with a green wire is shorted to ground.. the alternator will charge uncontrolled.... if the rotor is shorted to ground.. it can max charge like you describe..one more thing... put some fresh batteries in your volt meter... i chased a charging system problem on day on my brothers car... the voltage kept getting higher and higher... turned out the battery in the volt meter was on its last leg.. most volt meters use the internal battery for a reference voltage.. the internal battery kept dropping in voltage.. and the displayed voltage kept rising..
when I pulled the plugon the regulator, it dropped to about 12.25 volts. could I have just got a bad regulator?
Thankyall for all your help so far but I still havnt got to the bottom of the problem. Do y'all have any more ideas because I can't drive my car with it overcharging like this and I can't stand to watch her sit. Thankyou
the voltage regulator could have been damaged by the voltage spikes....pop a new one on...some autoparts stores actually have a tester for voltage regulators also...
i stole the one on my 71 dart and tried it and it did no good. everyone that I have talked to says that they think it is a bad ground.Wouldnt the altenator be grounded through the block?? or do they mean somewhere else in the harness?? thanks wayne for your help so far!!
these systems are fairly simple...switched power down the blue wire to the center terminal of the voltage regulator and to one of the brushes on the alternator...the green wire from the other brush connects to the side terminal on the voltage regulator..the voltage regulator is grounded... it monitors the voltage on the blue wire... the electronics inside pulse the green wire to ground inside the voltage regulator.. the longer pulse is grounded.. the higher the output voltage of the alternator...somebody else mentioned that they had found a broken wire right at the rubber voltage regulator connector.. and replaced the connector pigtail to repair the problem...here is a link to a 72 D100 wiring diagram... the upper left corner has the voltage regulator and alternatorhttp://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/05/2c/4b/large/0900c15280052c4b.gifcheck your private messages...