More electrical questions/help

[DodgeGuy]

Ok, so I have the new forward light assembly reinstalled, and all lighting is working great.

I also have the new ignition wiring back on, and had the rusty/corroded MSD distributor cleaned and the car started right up and ran as strong as ever, like it did last year when I parked it, so that's great.

But onto the charging system, which started all of this.

So again, new wiring harness installed.  I then installed the 10 gauge wire directly from the alternator stud to the starter relay.  I also hooked the original alternator stud wire back up as was suggested here, so I have power running through the 10 gauge wire directly to the battery, and also power running through the original alternator wire into the bulkhead connector, and into the ammeter.  I had both wires on the ammeter wired to one stud, but I put them back the way they were from the factory because I wanted to see what the ammeter would read.

So, again, the car started right up and runs great!!  However, the ammeter is still reading a discharge.  So I hooked my multi-meter up to the battery and it's showing the battery charging at approximately 18.5 volts!!  This is much too high correct?  Isn't it supposed to be around 14 volts?

So, just out of curiosity, I took the bypass wire completely off the alternator and the starter relay...and ran it again.  This time the ammeter gauge needle BURIED itself completely to the discharge side, instead of just a little like it did with the bypass wire on....but it still read around 18.5 volts.

So, if it's charging like the multi-meter says, why is it still reading a discharge?  Now, full disclosure, does it matter which wire goes to which post on the ammeter?  When I hooked them back up the factory way, I couldn't remember which wire was on which stud, but I didn't think it would matter...but does it?

Secondly, what's causing it to charge at such a high voltage?  Could it be the voltage regulator?  Isn't that responsible for regulating the output of the alternator?

[Brads70]

Yep sounds like your VR is bad or alternator. Make sure the VR is grounded well to bare metal. ( notice on the vr the one screw mounting surface has the paint ground off )Often freshly painted cars have an issue because the paint prevents a good ground. To make double sure it wouldn't hurt to make up a small grounding wire from the VR screw to the engine .
I also run the wire from the alt to the battery and when I did have the Ammeter hooked up it didn't read right/accurate. I bolted the wires together and wound tape around them.

[DodgeGuy]

Yep sounds like your VR is bad or alternator. Make sure the VR is grounded well to bare metal. ( notice on the vr the one screw mounting surface has the paint ground off )Often freshly painted cars have an issue because the paint prevents a good ground. To make double sure it wouldn't hurt to make up a small grounding wire from the VR screw to the engine .
I also run the wire from the alt to the battery and when I did have the Ammeter hooked up it didn't read right/accurate. I bolted the wires together and wound tape around them.

Yep, I happened to have a new voltage regulator from when I was originally having charging problems, and put that one back on and the voltage dropped down to about 14.6-14.9....and right now the car is idling very high, so I would guess that's why it's up in the high 14's.

But what I still don't get is why the ammeter is showing a discharge when the multimeter shows that the alternator is clearly charging?

Also, I haven't wired the little box that I believe regulates the voltage to the electronic choke control.  With that box not hooked up, would that cause the idle to run/race so high?

[1 Wild R/T]

First, you answered your own question, the wires to the ammeter do matter.... Yours are reversed... Yes it sounds like the regulator could be the issue but as brad suggested the regulator needs a good ground, but it also needs a good voltage reference signal, the fact the regulator i able to cause the alternator to charge means it must have a good ground, but if it can't read the voltage on the blue wire it grounds the green wire which causes the alternator to charge...

[RUNCHARGER]

Yes: You have the ammeter wires reversed.

[Chryco Psycho]

14.6v is normal charger rate

[DodgeGuy]

Ok, a morning update from last night (and FWIW, it's been a LONG time since I was out in the garage at 10:00 at night working on a classic Moper Muscle Car    lol)

In any event, I found the idle speed adjustment screw on the carb and adjusted the idle down (in my defense, I had purchased this car at the end of October last year, just before it was time to go into winter storage and didn't have time to "learn" the car at all until being thrown into the fire over this charging issue and rewire job.  Let's just say I'm learning this car at an exponential rate)

Anyways, even after switching the wires around on the ammeter, it's STILL showing a discharge. However, when I put my multi-meter on the battery it's showing a charge of just over 15 volts...it fluctuates from 15-15.25 volts.  So the battery IS charging. Should I be concerned that it's charging a bit "high"?  (this number is down from 18.5 volts it was charging at before I put on the new voltage regulator).

With the 10 gauge "bypass wire" off, and letting the charge pass through the stock wiring only (through the bulkhead connector, ammeter, etc.) it was around 14.6-14.9 volts.  When I put the 10 gauge bypass wire back on (and kept the stock alt. wire on it too), it was steady at around 15.25 volts.  FWIW 

I suppose it would be a bit ironic to go from having no charge to too much charge.

But still, the ammeter needle was slightly in the discharge even after switching the wires.  I'm starting to conclude that the ammeter itself is just bad, because the multi-meter is showing the alternator charging.

[Brads70]

Maybe the battery has issues? 

[dodj]

The reason you have different charging voltage numbers is because of corroded/dirty connections. Clean the bulkhead connectors and the ammeter connections first and see how much/if the numbers change. Ideally, they should be the same with or without the bypass. The VR reads voltage after it has passed through the bulkhead and ammeter connections. When those connections are dirty they cause a 'voltage drop' across them. If each dirty connection 'dropped' a half a volt, the VR would command an o/p of 15.5v in order for the voltage at the VR to be 14.5v. (Which it approximately where the VR is trying to keep the voltage)

[1 Wild R/T]

The reason you have different charging voltage numbers is because of corroded/dirty connections. Clean the bulkhead connectors and the ammeter connections first and see how much/if the numbers change. Ideally, they should be the same with or without the bypass. The VR reads voltage after it has passed through the bulkhead and ammeter connections. When those connections are dirty they cause a 'voltage drop' across them. If each dirty connection 'dropped' a half a volt, the VR would command an o/p of 15.5v in order for the voltage at the VR to be 14.5v. (Which it approximately where the VR is trying to keep the voltage)

[DodgeGuy]

A quick update.

I took the Challenger out for bit of a "shakedown" cruise, mainly local streets in our small town, out on the highway for about 3-4 miles of highway driving, and everything worked very well.

The car is running very nicely, I adjusted the idle a bit more.

The ammeter doesn't seem to be showing a discharge anymore, and according to my multi-meter the alternator was charging at 14.75 or so, which is great.

So, I owe a HUGE thank you to several of you guys for helping me out on this so much.  1 Wild R/T, Chryco Psycho, Runcharger, several of you helped a ton!!  Thanks!

[RUNCHARGER]

The ammeter gauge does move though I imagine? Does it show a slight charge at higher than idle?

[Chryco Psycho]

Glad to help , I assume you still have the 10 ga bypass connected ?

[Mpdlawdog]

 

[DodgeGuy]

Glad to help , I assume you still have the 10 ga bypass connected ?

Yessir...I have the 10 gauge bypass wire and the stock wire going to the ammeter as well.