Please read title. Now I find the ignition module and voltage regulator have smoked and eaten paint off of not only, the inner fender well under and around the ignition module, but the hood above it. A little under and around the voltage regulator too. I know I need to replace both but could there be more wrong? Thanks
Amp gauge showing around 20 amps whole time I was driving.
- Thread starter shags72
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The electrical gurus will want to know the vehicle that you are dealing with. The more info, the better. 
67Dart273
Well-Known Member
1..YUP. Make model year and is it stock
2...Run over to MyMopar.com and download the closest you can get to a service manual. You may have to settle for Dodge vs Plymouth, etc
3...Take your meter and check battery voltage when warmed up and running at fast idle to simulate low to med. cruise RPM
4...You have any other mysterious electrical failures, such as lamps or radio?
2...Run over to MyMopar.com and download the closest you can get to a service manual. You may have to settle for Dodge vs Plymouth, etc
3...Take your meter and check battery voltage when warmed up and running at fast idle to simulate low to med. cruise RPM
4...You have any other mysterious electrical failures, such as lamps or radio?
Here we go again, get your crystal ball out so we can diagnose and help fix the problem. LMAO
Easy guys- he has only 42 posts. He may not recognize your sarcasm. I mean you’re 100% correct and this topic has been covered 1bazillion times already. Just check search feature. LMAO.
Syleng1
Syleng1
Please tell us whether it was showing charge or discharge, and how long you were driving.
because for example
20 amps charging for 5 minutes could simply be a low battery, or could be something else.
20 amps charging for 20 minutes is something else
20 amps discharging is likely a short.
The ammeter only indicates whether power is flowing in or out of the battery.
Other than starting, the car normally draws power from the alternator.
The alternator recharges the battery after starting. The gage should indicated charging for a few minutes and then go to zero (centered).
Power does not flow through the ammeter after the battery is recharged (unless there is equipment wired to the battery side).
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Allright! Damn! If I'd have known what to put I'd have put it in the question. I was hoping that someone would just say ask me more so I could figure this out. It's a 72 Dart with a repro wiring harness with dual ballast. showing 20 amps charge anything over idle. It's an old alternator and was an old module and regulator. Like over 25 years old but not many miles really. Maybe 12k. Having it melt out the sealer or whatever that crap is, out of both of these is pretty crazy. I don't have anything wired up aftermarket not even a stereo. I'll have to check off idle voltage after I install the module and regulator. I had to jump it this spring but the carb was dry and it didn't get fuel for a while so I charged it and haven't had an issue with that since. Haven't driven it much this year.
Not enough info to provide a specific answer.
But enough info to provide some guidance in solving the problems.
1. If the dead battery was charged by running the car, especially at high idle, then its possible that damaged occured.
2. Overheating of both the VR and the ECU could be from overvoltage, or damaged wires. Could be a short.
Post some photos and maybe one of us will see or can deduce something.
I would suggest investigating the components.
Start with the alternator. See if either brush is grounded (they shouldn't be for a 72)
With the green field wire (R3) disconnected from the alternator, check if that is grounded (it shouldn't be)
Not all 72 Model year cars came with the ECU. Although those that did, came with the double resistor. On is 5 ohms and helps regulate power to the ECU. The other is 0.5 ohms and controls power to the coil (except at start).
Functional Schematic for isolated field alternator and original ECU ignition
Alternator brushes and field terminals shown here
www.forabodiesonly.com
But enough info to provide some guidance in solving the problems.
1. If the dead battery was charged by running the car, especially at high idle, then its possible that damaged occured.
2. Overheating of both the VR and the ECU could be from overvoltage, or damaged wires. Could be a short.
Post some photos and maybe one of us will see or can deduce something.
I would suggest investigating the components.
Start with the alternator. See if either brush is grounded (they shouldn't be for a 72)
With the green field wire (R3) disconnected from the alternator, check if that is grounded (it shouldn't be)
Not all 72 Model year cars came with the ECU. Although those that did, came with the double resistor. On is 5 ohms and helps regulate power to the ECU. The other is 0.5 ohms and controls power to the coil (except at start).
Functional Schematic for isolated field alternator and original ECU ignition
Alternator brushes and field terminals shown here
Identifying Chrysler Alternators (1960-1976)
Roundback and Squareback refer to the style of housing. Roundback through model year 1969. Roundback for model years 1970-71 usually has a slightly different rear housing Squareback Revised Squareback Is most easily differentiated by the thin middle between the housings. Overall these...
www.forabodiesonly.com
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Phreakish
Well-Known Member
There's a few necessary skills and tools to diagnose and repair the electrical system.
A test light, a volt/resistance meter and a way to measure current. A test light can do it all, but you need to be pretty well versed in it's use. A small digital multimeter is often easier for a newbie.
Next, you need to sit and understand how the charging system works. The votmage regulator feeds current to the rotor (the spinny part) which induces a current in the windings (the not spinny part) which goes through diodes and then on to the battery. If the regulator, alternator, battery, or any number of places within the wiring become damaged then the voltage or current or both can spike and the magic smoke comes out.
You'll want to get the alternator bench tested because if it's junk, it can do a ton of damage and is easy to detect on the bench without burning down the car. Don't just blindly replace it, I'd guess you have a 60% chance of getting a worse one off the shelf.. Test yours first.
If the alternator is good, you then need to use a test light or voltage/resistance meter to trace the wiring and rule out shorts or broken wires.
It also wouldn't be a bad idea to pull your cluster and check the ammeter wiring and gauge for damage.
It's not uncommon for naive owners to replace "fusible links" (Google it) with normal wire and then when an issue happens it results in what you've experienced (or worse). Often they are spliced poorly too and cause their own failure at some point,sl so look for evidence of hacked wiring and start there and trace it to figure out what's what. The fixes aren't hard, it's mostly time and a few bucks in wires or replacement harnesses and modules.
The fact that your ignition module got smoked suggests an over-volt or over charge situation. Or if you've ever left the car with the key "on" but the engine off for an extended period, you can kill the coil and then other components in that circuit too. Other members are more experienced in that particular department though and are likely to chime in if I'm off base with that.
A test light, a volt/resistance meter and a way to measure current. A test light can do it all, but you need to be pretty well versed in it's use. A small digital multimeter is often easier for a newbie.
Next, you need to sit and understand how the charging system works. The votmage regulator feeds current to the rotor (the spinny part) which induces a current in the windings (the not spinny part) which goes through diodes and then on to the battery. If the regulator, alternator, battery, or any number of places within the wiring become damaged then the voltage or current or both can spike and the magic smoke comes out.
You'll want to get the alternator bench tested because if it's junk, it can do a ton of damage and is easy to detect on the bench without burning down the car. Don't just blindly replace it, I'd guess you have a 60% chance of getting a worse one off the shelf.. Test yours first.
If the alternator is good, you then need to use a test light or voltage/resistance meter to trace the wiring and rule out shorts or broken wires.
It also wouldn't be a bad idea to pull your cluster and check the ammeter wiring and gauge for damage.
It's not uncommon for naive owners to replace "fusible links" (Google it) with normal wire and then when an issue happens it results in what you've experienced (or worse). Often they are spliced poorly too and cause their own failure at some point,sl so look for evidence of hacked wiring and start there and trace it to figure out what's what. The fixes aren't hard, it's mostly time and a few bucks in wires or replacement harnesses and modules.
The fact that your ignition module got smoked suggests an over-volt or over charge situation. Or if you've ever left the car with the key "on" but the engine off for an extended period, you can kill the coil and then other components in that circuit too. Other members are more experienced in that particular department though and are likely to chime in if I'm off base with that.
I will take a look at the suggestions and thank you Mattax and Phreakish. Probably won't be until the weekend though. Sorry I didn't give enough info but I've been lucky enough not to have strange electrical issues before so haven't had to ask for help much on this subject.
Phreakish
Well-Known Member
Year/make/model helps a ton with most issues because 'a bodies' covers a lot of ground and a lot of different systems designs, and many members come here for help with non-abody stuff too. Even with year/make/model things can vary. Photos are always helpful too because it's a lot easier to tell if your car has been monkied on previously and the usual help may not actually help.
There's a bunch of helpful members here that will help get you sorted once all the info is available.
I just thought about this and the engine is actually a 73 but the car always had electronic voltage regulator in it so I don't think it mattered much. The original engine harness was points and a friend cobbled it to electronic ignition. So when I redid the car I bought a new one and no monkeying with it. I will put some pictures in when I work on it this weekend. Thanks again!
I am sorry guys, wasn't able to get to it this weekend. All the daily drivers had issues, so the old man was called in to fix em. I'll try to get this back together this week and start it up and test some stuff from your suggestions.
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