73 Cuda, Amp gauge needle barely moves

[Titan1969]

Thanks in advance.

My 73 Cuda amp gauge barely moves even during starting, turning lights on, etc.
I am getting 13.5 -13.8 volts while the car is running, however the needle on the gauge just sits in the middle.
I have already replaced the gauge and no change.
The car has a Painless wiring kit.

The needle does slightly bump (very slightly) when starting.

any ideas?

 

[72RoadRunnerGTX]

Are you sure that aftermarket wiring has not by-passed the ammeter altogether or has been by-passed in the engine compartment? Wired and loaded correctly, fully charged battery, there should be little to no current flowing through the ammeter while the engine is running. What are you expecting the ammeter to show?

 

[pschlosser]

On my car with original ammeter, the meter moves, at best, 1/4 needle width between varying loads. Yours could be working correctly.

 

[Titan1969]

on other Mopars I have owned (73 Challenger, 74 Duster) when I turn headlights on for example, the guage would jump up to charge then settle back to center. My Cuda does not. Also when I crank the car a few times (after its sat for a few weeks) on my past Mopars the gauge would rise up to 1/3 towards charge then slowly come back to center. Mu Cuda moves at best off center the width of match stick...sorta like it sees charging but doesnt show the right charging % on the gauge.

 

[Xcudame]

There is a lot of variances between different gauges. I'd buy an inexpensive voltage gauge from Summit and temporarily install it to ensure your electrical system is all OK.

There's a reason why all the new Mopars have voltage gauges now instead of amp gauges. With an Amp gauge, all the circuit amperage has to go through the gauge (and firewall!) in series. There were and are numerous failures of the old Mopar amp gauges and wiring/connections. With a voltmeter, you can get a simple reading in parallel.

 

[72RoadRunnerGTX]

There were and are numerous failures of the old Mopar amp gauges and wiring/connections. With a voltmeter, you can get a simple reading in parallel.

Is that a fact? What back-up do for have a statement like that? With correctly maintained connections, correct load placement, and operated within its design limits, ammeters and/or their connections don’t fail. Voltmeters alone don’t tell the whole story, may as well run a charge/no-charge idiot light.

 

[Mopars & Missiles]

Is that a fact? What back-up do for have a statement like that? With correctly maintained connections, correct load placement, and operated within its design limits, ammeters connections don’t fail. Voltmeters alone don’t tell the whole story, may as well run a charge/no-charge idiot light.

Agree.......

There is so much misunderstanding (and ignorance) of how the OE charging system works that is posted on the internet. That leads to many statements (and falsehoods) about the ammeter and the (unnecessary) need to eliminate it. Fear is created by ignorance of the facts.

Keep on leading the way to the light (truth) 72RoadRunnerGTX, your videos are very good and easy to follow. (but then, I have an electrical background. Most don't unfortunately)

Electrons CAN be your friends!

 

[pschlosser]

Fear is created by ignorance of the facts.

Fear is also created to sell you something, something you may not really need.

 

[Mopars & Missiles]

Fear is also created to sell you something, something you may not really need.

Agree with your statement, lots of times the person telling you to eliminate the ammeter is financially motivated (ie, trying to sell you a product that, as you pointed out, you don't need).


Just another thought comes to mind, Painless wiring kits are ANYTHING BUT painless in my limited experience.

 

[EW1BH27]

@Titan1969 your amp gauge certainly doesn’t sound like common/normal operation as to what I’m familiar with also. Mine swings noticeably after trying to start the car a couple times, not to mention when I raise the top with and without the engine running.

If you have means to boost the your car I’d be curious to know how your gauge behaves if you drain the battery. Like leave the lights on until they or the battery dies. Kind of a drastic experiment, wish I had more to offer.

 

[Challenger RTA]

The matter of fact is. Bad connections heat up burn and then cause a fire. It's not the amp gauge it's the connections. Bulkhead connections and others. The design is outdated. I would say that's the reason you don't see that design used any more.It's not the only one I have seen using that configuration. In the first place. I would have to say it was bean counters decision.
A new harness is only a temporary fix for a daily driver. Maybe decades for an occasional driver.
I removed mine because of that fact. The wires that connect to the amp gauge wire melted together and also melted the Brown ignition start wire under the dash. (Case and Point. Close to the bulkhead connector.) I had my suspicions when I was not seeing very little movement if any at times on the amp gauge.
In the early to mid 70's I did a lot of night driving to the base. It would be a 6 to 8hr trip depending on the rapid rate on the four lane The clock would be in the three digit area a lot of times. And of course the high beams where on for a prolonged period of time. (I did not blind other drives, But that's juts me.) That being said I would always smell something electrically hot. It took me a little while to figure it out but I did. I was the foot dimmer switch. That is one of the high currant loads that are a problem. If all the wiring is in good condition. I would still use a charging bypass and relay circuits for high currant loads. Then you still retain the amp gauge for esthetics.
The proof has been in the pudding for a good while or this would never come up. A problem is not a problem unless it's a habit!
When in the USN there is a lot of training. I had damage control training, fire school three times. You get put in a multi story building and they light it UP! You have to fight you way through it.
When aboard a ship if you get shot at there will be return fire. If there is high water in the boiler and you go dead in the water, it can be dealt with. When I comes over the 1MC. FIRE! FIRE! FIRE! THIS IS NOT A DRILL! It's like lighting strikes everybody's ass. Fire is so unpredictable and you always take measures to prevent it from ever happening. So take heed and do as you like.

 

[72RoadRunnerGTX]

Heat is the result of current and resistance. If you maintain your current and resistance below their accepted design limits for this system, there won’t be any heat. You describe wires melting, as original, 12 ga charging system wiring melting is an indication of excessive current for that systems design. That falls under the category of being operated outside of its original design limits. Can’t blame the ammeter. Added loads at the battery? Higher wattage than stock headlamps by-chance on the factory headlight wiring? That too, places more current stress on not only the headlight wiring, connections and components, but the charging system as well if relays are not used or the relay secondary power is placed at the battery.

Charging by-pass? Careful with that, the way most promote it, bypasses the stock circuit protection as well, exposes all factory un-fused wiring to a verry high current potential in the event of a short.

 

[Challenger RTA]

There was no extra or excessive loads or current at that time in the mid 70's all stock. Nothing added.No high wattage headlight no fog lights no aircraft landing light or radar detector. Wish I had one back then! I'm not blaming the amp meter. It's the excessive resistance from corrosion and loose connections.The ends become hard and brittle.
As far as the changing or load bypass how ever one whats to refer to it. There is a fusible link to the wiring and or to splice one the load.The alternator should be connected to the battery up stream of the fusible link. And there should be no need to have the alternator feed fuse. The diodes should blow in case there is a problem. But it still would hurt to have it protected.
The original design is inadequate after a time of use. It's not realistic for most people to do maintenance on weakly,monthly or yearly bases As you would do like checking fluids and tire pressure.

 

[72RoadRunnerGTX]

By far, the most “pushed” by-pass option I see is a “under-hood” or “engine compartment” straight alternator to battery add-on by-pass using large diameter cables. No other changes to the stock charging system. Promoted as removing current stress from all stock wiring and connections. With or without its own fusible link. Either way, it by-passes all stock un-fused circuit protection altogether.

 

[Challenger RTA]

No other changes to the stock charging system

There are changes that I have done to correct that as I have said. But I have not fully explained. The Battery feed to the fuse box is on a fusible link and as is the load feed to splice one. Not to many people have the know how with out a full explanation. Originally the alternator that feeds splice one was never fused. The alternator is now connected directly to the battery is electrically the same as the original. Just not going through the bulk head connector. With the exception of having a working amp gauge. Keeping in mind the power feed connections are upstream of the fusible link. Now I have a under hood fuse box relay setup for additional loads.That is connected to the battery and alternator. There are other changes that I have done to remove the high current from the bulkhead connector. Added a 6 circuit fuse box for acc under the dash with it's own power supply. The list could go on.

 

[72RoadRunnerGTX]

Wasn’t specifically addressing what you have done.

There are weak spots in this original design, Packard terminals used in the charge path at the bulkhead connector being the weakest link by far. Then again nothing about these cars were designed to still be around 50+ years later.

BtW, When I refer to electrical maintenance, not talking about scheduled or periodic maintenance per se. Talking about knowing the current state of the cars electrical system always, maintaining it in proper working order. Especially circuits that handle any kind of significant current loads. A majority of these remaining old Mopar’s are not daily drivers and have changed hands numerus times since they were new. Most have had their wiring messed with repeatedly by countless people with unknown, or clearly no, electrical skills. The biggest problems I run into on these cars is the work of the last guy who touched it.

 

[Challenger RTA]

Packard terminals used in the charge path at the bulkhead connector being the weakest link by far

That I could not agree with you more.

When I refer to electrical maintenance

I understand your reface now. Maintenance to me is an scheduled act to keep something in good condition. The butchery that goes on before changing hands is a problem. I saying that there should been minimal problems when they were daily drivers. They were considered disposable at the time.

 

[Xcudame]

I find it interesting that Mopar taxi cabs and police cars all had the wires going through the firewall in a separate hole to the ammeter bypassing the terminal block. That tells me right there Chrysler new there was a potential problem. I bought a lot of nice cars to chop up for race car parts back in the day because someone had an electrical melt down under the dash usually caused by some killer amp stereo.
I agree maintenance is important, but people didn't really think about wiring back then and now that these cars are over 50 years old, it's a testament to Chrysler we still have so many examples! Remember when these E-Bodies were built, they were expected to last no more than seven years!

 

[Challenger RTA]

Wasn’t specifically addressing what you have done.

What I did. Really comes down to primary and secondary circuits. That I know you understand.

 

[Titan1969]

By far, the most “pushed” by-pass option I see is a “under-hood” or “engine compartment” straight alternator to battery add-on by-pass using large diameter cables. No other changes to the stock charging system. Promoted as removing current stress from all stock wiring and connections. With or without its own fusible link. Either way, it by-passes all stock un-fused circuit protection altogether.

thx for this. Ill trace the wires from amp meter back to alternator. Maybe the resto shop did not wire the amp meter to correct wires. Maybe just to a 12 volt line and not amp line.