My 67 Coronet needed the original alternator replaced maybe 7 months ago and ever since Ive been through 3 alternators, 2 regulators, and reran all new wiring. Ive charged the battery (which is 6 months old) and the alternator will NOT charge sufficiently. With just idle and no loads the battery puts out 12v and the alternator 11.8v. With all loads on and the throttle open to about 2k rpm the battery puts out 10.5v and the alternator jumps down to 10.1v I have no idea whats going on and its been an ongoing problem for months. Its starting to really **** me off and I havent been able to find anyone near me that has ideas or can come in person to look at it. I really dont have the to pay a shop to do anything.

 

could it be the wrong size pulley on the alternator? if not find a high output alt. like the ones in the service vehicles.

 

the pulley is correct, I double checked that the alternator is exactly what's supposed to go on the vehicle. I am actually waiting on a local place to call me when my battery charge/test is done just in case. I am also going to bring the brand new alt up there since the place I bought it from today was having problems with their machine.

Also, where does the direct battery cable go through to eventually end up at the alternator? I know on newer vehicles with internal regulators the battery cable comes directly from the battery. Ive been looking at a schematic but its totally different from the evtm's I'm used to.

 

alternator output is 11.7v throttle off and around 10.9v with throttle on with all loads turned on. Yes, it is grounded. I ran a new wire from the regulator to the alternator and checked it for opens, cuts, burn marks, etc. I have also adjusted the regulator according to the manual. I do not think it's bad but I don't know of any simple ways to really check to see if the component is still good.

 

yeah, I took readings from idle and 2k rpm and still bad. I just got back from the shop and both the new alternator and battery are good so I need to start looking at other things. I retested the output and at idle battery was at 12v and alt was at 11.3v and when I opened the throttle the battery stayed at 12v and the alt jumped up two tenths to 11.5v. A little better but not quite good enough to run the vehicle. Possibly a regulator problem?? A new one costs maybe 15-20 bucks if I remember right.

 

could be

 

nope nevermind i only have the newer ones

 

I'm seriously thinking about selling it because of the money it's sucking out of me, which now I'm totally broke lol. But I have faith in it I won't give up until I really have to. If anyone lives in my area I would LOVE to have you come have a look at it if possible

 

yeah I have considered it but haven't tried it. Which connection would it go to on the alt? Its a one post alt, just one Fld(F) from the regulator and the one that leads to the Ammeter(B)

Heres the schematic I've been using: A is inside the car and B is the engine compartment
http://www.google.com/imgres?imgurl=...num=1&ct=image

 

dont give up on her. if you do it just means a chevy guy has won

 

and really, it has only burnt up the new one when I first put it in and test drove it. It worked decently and then all of a sudden it jumped to like 15v and I smelled it burning. I cleaned the build-up on the contact plates inside the old original regulator and adjusted it as specified in the manual I have. After the second alternator I bought was installed it didn't work right for a week then all of a sudden it charged and ran all the electric correctly for like 3 weeks then died again. I noticed during that time everything worked fine except the headlights were a little dim and flickered so I only drove it during the day.

 

do I disconnect the field wire thats running from the regulator first or leave it on?

 

alright. If it turns out like 13 Ill be happy but if not I have no idea where to go from there. Maybe the headlights to check their connections idk. It is starting to narrow down but the wiring is so caked in gunk it's hard to really see where everything leads. Can barely see the colors anymore. When I got the thing I had to replace intake gasket, oil pan gasket, rear main, and valve cover gaskets plus both tranny line connections into the radiator so yeah lots of baked on fluid lol.

 

rent or borrow a steam cleaner and just plug up the intake it will take off pretty much all of that gunk. take off the spark plug wires too. try some simple green first. just spray it on and then steam it off. it makes it a lot nicer to look at and work on. and if you clean it you can hack a lot of heat off. after i steamed my engine off it ran about 20 degrees cooler. also you could have something that could be draining your car bad enough to put too much strain on the voltage regulator.

 

a simple test for voltage drop {exc essive resistance} in the charging circuit.

Disconnect ignition wire at the coil side of the ballast resistor.
Connect a volt meter between the positive batt terminal and the field term on the voltage regulator.
Turn the key to the on{run} position.

Read the volt reading on the meter.
It should be less than .55

If it is higher than .55, you have excessive resistance in the circuit somewhere. [probably a bad/corroded connection].

Bad connections possible:
batt terminal conns.
solenoid
bulkhead connector
ignition keyswitch
ammeter in dash

 

So safety first for those of you watching at home...I agree completely with omaha,just make sure that your meter is set to volts not ohm's, you will toast your meter, this may let the smoke out of a few things.

 

right lol. Theyve been cramming electrical procedures down our throats at the tech center so Im pretty familiar with the whole voltage drop thing. I'll try doing that and post the results

 

ok did the full field test and it read only 12.2v. Is that good? I used a #6 wire so that should have been plenty of juice. Gonna go outside and do that voltage drop test like theomahamoparguy said.

 

ok I found something unusual. Theres is a wire going from the alternator to the horn relay. Is this normal?? I was trying to figure out why there was a wire going to the ammeter and one somewhere else and thats where I found it leading to.

 

I tried something else just to see what happens. I bypassed the ammeter and put a jumper from the batt positive to the batt prong on the alternator and it showed 12v idle and 2500 rpm w/ lights on and off. Would this help anything in finding the problem?

 

ok I posted an ad on craigslist and got a few phone calls. One guy said ground the screw where the second fld post would have been. Another two said replace the regulator. Then the last two said 100% it was the ammeter in the dash and that theyve had a lot of cars that had that problem. Ill try that tomorrow.

 

Sometimes the horn relay is used as a convenient connection point for other hot leads. It has 12v always . Its mounted near the batt right?

 

[as noted from above]
You bypass the gauge [ammeter] this way, it bypasses all the connections. Most of the 'juice' is going right to the batt instead of through the ammeter. This is ok; just put in a voltmeter and forget about the ammeter. They are not that great anyway {for various reasons}
{Bulkhead etc}
Yes, if you have the dual field alt and the the old electromechanical regulator you must ground one of the field terminals. Just run a wire from the field terminal to one of the case bolts on the back side of the alt.

Factory ammeters are only good for about 40[?] amps. when all is 'right'.
I used an alt. listed for an 89 chrysler fifth ave and an electronic voltage regulator on a 64 dart and bypassed the ammeter {used voltmeter instead}. Got about 13 volts at idle. Bright, non flickering headlights too.

 

Would an electronic regulator just bolt right in place of the mechanical one using the same connections and everything? And the alternator isnt listed as a dual field and it doesnt have the second prong, just a screw where the second prong would be. Also I am trying to tremove the cluster to just run a jumper between both sides of the ammeter. The way I have it hooked up right now has it being connected the alternator in two places which is dumb. The current jumper also runs across the engine lol it was totally temporary.

I am stuck as to how to remove the cluster. I took out all the screws holding it in place and took off the radio/heater *****. Now the radio and heater controls are back behind it dangling which is fine but I can't get to anything back there to disconnect the electrical connections. The big climate control box is right in the way. I dont need to take the whole dash off to get to the cluster do I?