Charging problem

[AR67GTX]

My 67 GTX hasn't been run in 3 months due to a bad radiator. Finally had it re-cored and installed new water pump. When I finally started it today, the battery spun it over OK. It took 4 primings of the carb and key starts before it filled the carb and kept running so the battery seemed to be doing it's thing.

After I got it running, I engaged the AC and let it idle while I topped off the radiator and sealed everything up. I sat back down inside and noticed the voltage was low - about 10 - 10.5 volts at idle with the AC compressor engaged and fan on high and the dash amp gage was showing discharge. I have voltage and oil pressure gages under the dash. I reved the motor up some but the voltage did not increase hardly any. It typicaly use to run about 14 - 14.5 volts or a little more once above about 1000 rpm falling to maybe 13 at idle with the AC on. I killed it and then re-started it and the starter seemed to turn a little slow so I decided to charge the battery.

I put a battery charger on it for a couple hours (slow charge rate) but although showing close to 100% charge it never did fully charge and go into a float stage. Voltage across the battery posts was about 12.6 V.

I decided to venture down the road in the car and see what it would do. It re-started fine but still had very low voltage. I turned the AC off and the voltage jumped up about 1.5 volts - maybe a little more. Turned the AC back on and the voltage drops back. But even with the AC off the voltage doesn't get back to the 14 - 14.5 volts it ran before. With the AC off the amp gage reads slightly positive but at 50 mph the voltage was only reading about 12.5 to 13. When I got back I killed the motor and it re-started fine.

I've had this car about 10 years and it has the usual rebuilt alternator on it of questionable output. I put a solid state voltage regulator on it when I first bought it and it has seemed to work OK - at least up until now.

How do I best trouble shoot this thing? Electrical is not my strength as beyond knowing enought to not hold a spark plug wire to my tongue - my skills are about tapped out. The shop manual isn't a lot of help as it mostly discusses testing components rather than basic system checks. I'm tempted to put a new rebuilt alternator on it but then I wonder if the voltage regulator has crapped out. And then the high voltage drop when I turn the AC on makes me wonder if the fan motor has about kicked the bucket and is pulling high amps. The battery could be an issue but it seems to be holding up. I'm leaving it on a charger tonight.

I have a decent multigage electrical tester and a few other things like a test light, so I can do some basic checks if anyone has any suggestions. I've read the trick of pulling the positive battery cable with the motor running is not a reliable test of the charging circuit and doesn't help pin-point the problem. I may still have the old mech voltage regulator also that I could re-install, but I will have to look for it.

Another note - I have a green knob battery disconnect on the car and I have problems with it not making a good connection but I assumed that would only cause a starting problem when amp draw was high.

Thanks in advance for any help.

Dan

 

[Pops1967GTX]

Well since its been sittiing for 3 months... First I would check all connection & grounds.. Test Battery...
From my manual testing alternator/regulator....
Battery test...
1. Connect the positive lead of the voltmeter to the positive terminal of the battery and the negative lead to the negative terminal.
NOTE: Protect your eyes with safety glasses or goggles when doing this procedure.
2. Remove the coil cable from the distributor cap.
3. Ground the coil cable to the engine block by connecting a jumper cable between the two. This will prevent dangerous arcing of the high-voltage spark.

NO-LOAD TEST
This test will determine whether or not the system is charging the battery and, if not, whether the alternator or regulator is at fault. It requires a voltmeter capable of measuring at least 16 volts, down to tenths of a volt.
If the charging system on your car has an externally mounted regulator, warm up the engine before performing the following test:
1. Turn off the engine, lights, and all other accessories.
2. Attach an engine tachometer according to the manufacturer’s instructions.
3. Connect the voltmeter to the battery by attaching the positive lead to the positive terminal and the negative lead to the negative terminal.
4. Note the voltmeter reading. If it is less than 12 volts, charge the battery. Then note the voltage reading again and record it.
5. Start the engine and slowly increase the speed to 1,500 rpm.
6. Note the voltmeter reading again. If it exceeds the engine-off voltage by more than 2 volts, the system has a faulty regulator, a poor regulator ground, or a short circuit in the wiring between the alternator and regulator.
7. If this voltage reading exceeds the engine-off voltage by less than 2 volts, perform a load test.
LOAD TEST
1. Keep the tachometer and voltmeter connected as they were for no-load test.
2. Note and record the voltage reading.
3. Start the engine and turn on the heater (or air conditioner) at high speed. Turn on all lights and accessories.
4. Increase the engine speed to 3,000 rpm and note the voltmeter reading.
5. If this reading exceeds the engine-off voltage by 1/2 volt or more, the charging system is functioning properly.
6. If his reading exceeds the engine-off voltage by less than 1/2 volt, perform a full-field test.

FULL-FIELD TEST
When the regulator’s control function is bypassed, the alternator runs full-field. The method of bypassing the regulator differs, depending on the type of vehicle. For this reason, Step 1 of the full-field test changes from car to car, while the remaining steps are the same for all models.
1C. Chrysler models. Turn of the engine. Locate the green wire connecting the alternator field terminal to the regulator; disconnect this wire from the alternator. Connect a jumper wire from the alternator field terminal to a good ground.
2. Once the regulator has been bypassed, repeat the load test.
3. If the full-field voltage exceeds the engine-off voltage by 1/2 volt or more, the regulator is defective and must be replaced...............do not jump the green wire to anything.
REGULATOR REPAIR
Once it has been determined that the problem is with the regulator and not the alternator, you can find out if the source is the regulator itself or its wiring or ground.
1. Check the wiring between the regulator and alternator for heat damage or wear. The regulator is usually mounted on the firewall or on the finder under the hood.
2. Remove the bolts from the voltage regulator.
3. Use sandpaper to clean off the area around the bolts and the spot where the voltage regulator mounts on the car. This will assure a good ground.
4. Clean, reinstall, and tighten the bolts.
5. Perform all of the troubleshooting procedures again to see if the problem still exists.
6. If so, the problem is either in the wiring or the regulator itself. If you have already inspected the wiring, try replacing the regulator


http://www.mymopar.com/charging.htm

 

[AR67GTX]

What manual is that from? It makes a lot more sense than all the gobbly gook in the Plymouth 67 Service Maual with acidity testing, 3-minute charge tests, VAT-20D testers, battery post adaptors, etc.

Battery is on the charger overnight. I'll run a copy of this off on the printer and see if I can wade my way through it tomorrow.

Thanks.

Dan

 

[440roadrunner]

As above, about the very first thing is to have the battery checked over. "Load tested."


One thing I would check is the circuit path from the alternator to the battery. Read this article which shows some of the problems, and a simplified diagram of the circuit path

IF there is resistance in that path, either the black or red going in/ out of the bulkhead connector, or in the ammeter itself or ammeter connections, you could "lose" a lot of voltage between the alternator output and the battery

To check this out, put one probe of a voltmeter on the alternator output stud, the other on the battery. Experiment with the engine running fast ("medium cruise RPM") with no load and with as much load as you can apply, IE heater blower/ AC/ headlights, etc

The lower this reading the better, but more than 1 volt or two at the outside is cause for concern.

Try the "full field" test to see if the alternator itself can keep up. You may have one or more bad diodes, or something else wrong which is limiting the output of the alternator.

If you have the original 67 system, the alternator should only have ONE field terminal. (Other is grounded). Simply clip - lead a wire from that terminal to the battery, and see if the alternator can keep up with accessories. MONITOR battery voltage, and do NOT allow the battery to go over 15V!!!

Be SURE it's not something simple like a belt

If the alternator seems to be putting out enough, replace the regulator. Please buy a good one. Standard Motor Products (Blue Streak) VR- 128 or Echlin/ NAPA VR1001. These look a little different than original, but hook up the same and are good quality

AFTER you make these checks post back.

 

[AR67GTX]

Here are the results of this testing. I put the voltage readings in parenthasis in the body of your post. The battery was fully charged this morning and it did seem to be more back to normal when I started the car.

Well since its been sittiing for 3 months... First I would check all connection & grounds.. Test Battery...
From my manual testing alternator/regulator....
Battery test...
1. Connect the positive lead of the voltmeter to the positive terminal of the battery and the negative lead to the negative terminal.
NOTE: Protect your eyes with safety glasses or goggles when doing this procedure.
2. Remove the coil cable from the distributor cap.
3. Ground the coil cable to the engine block by connecting a jumper cable between the two. This will prevent dangerous arcing of the high-voltage spark.

NO-LOAD TEST
This test will determine whether or not the system is charging the battery and, if not, whether the alternator or regulator is at fault. It requires a voltmeter capable of measuring at least 16 volts, down to tenths of a volt.
If the charging system on your car has an externally mounted regulator, warm up the engine before performing the following test:
1. Turn off the engine, lights, and all other accessories.
2. Attach an engine tachometer according to the manufacturer’s instructions.
3. Connect the voltmeter to the battery by attaching the positive lead to the positive terminal and the negative lead to the negative terminal.
4. Note the voltmeter reading. (13.1 volts right after taking the charger off of it). If it is less than 12 volts, charge the battery. Then note the voltage reading again and record it.
5. Start the engine and slowly increase the speed to 1,500 rpm.
6. Note the voltmeter reading again. If it exceeds the engine-off voltage by more than 2 volts, the system has a faulty regulator, a poor regulator ground, or a short circuit in the wiring between the alternator and regulator. (On my meter voltage was reading 14.4 to 14.5 volts. Inside the car the gage was 14.3)
7. If this voltage reading exceeds the engine-off voltage by less than 2 volts, perform a load test.
LOAD TEST
1. Keep the tachometer and voltmeter connected as they were for no-load test.
2. Note and record the voltage reading.
3. Start the engine and turn on the heater (or air conditioner) at high speed. Turn on all lights and accessories. (AC and lights on. First try was only about 12.3 V but I was getting belt slipping. I tightened the belts and in eventually climbed to 14.1 volts at around 3000.)
4. Increase the engine speed to 3,000 rpm and note the voltmeter reading.
5. If this reading exceeds the engine-off voltage by 1/2 volt or more, the charging system is functioning properly.
6. If his reading exceeds the engine-off voltage by less than 1/2 volt, perform a full-field test.

FULL-FIELD TEST
When the regulator’s control function is bypassed, the alternator runs full-field. The method of bypassing the regulator differs, depending on the type of vehicle. For this reason, Step 1 of the full-field test changes from car to car, while the remaining steps are the same for all models.
1C. Chrysler models. Turn of the engine. Locate the green wire connecting the alternator field terminal to the regulator; disconnect this wire from the alternator. Connect a jumper wire from the alternator field terminal to a good ground.
2. Once the regulator has been bypassed, repeat the load test.
3. If the full-field voltage exceeds the engine-off voltage by 1/2 volt or more, the regulator is defective and must be replaced...............do not jump the green wire to anything.(Engine off voltage starting was 12.74 volts. Reving the motor brought the voltage to a steady 12.25 volts)
REGULATOR REPAIR
Once it has been determined that the problem is with the regulator and not the alternator, you can find out if the source is the regulator itself or its wiring or ground.
1. Check the wiring between the regulator and alternator for heat damage or wear. The regulator is usually mounted on the firewall or on the finder under the hood.
2. Remove the bolts from the voltage regulator.
3. Use sandpaper to clean off the area around the bolts and the spot where the voltage regulator mounts on the car. This will assure a good ground.
4. Clean, reinstall, and tighten the bolts.
5. Perform all of the troubleshooting procedures again to see if the problem still exists.
6. If so, the problem is either in the wiring or the regulator itself. If you have already inspected the wiring, try replacing the regulator

A couple other notes. Starting voltage was about high 10s to low 11 volts when cranking. I noticed that with accessories off my inside volt gage reads pretty much the same as my meter hooked up to the engine. But, as I engage accessories, the inside voltage is dropping below what the engine side meter is reading - maybe as much as 1-1/2 volts or a little more - especially at lower rpm. I cleaned up my bulkhead connector many years ago - could this be an indication it needs attention again? Or maybe some bad grounds?

It looks like the battery was just low and the charging system is working from this. Still a little surprised by the voltage display on my interior gage as I don't recall it dropping as low as it is before. It usually read around 14 or more volts going down the road.

Thanks for the help

Dan
http://www.mymopar.com/charging.htm

 

[AR67GTX]

Well - there's nothing like going about things in reverse order and doing basic maintenance last. I pulled all the cables off and bronze brushed the dry powder off of them and uplugged the bulkhead connectors and plugged them back in. Now it acts like it's old (it is old) self - the alternator jumps at the slightest touch of the throttle and the inside voltage is up around 14 volts holding steady. I've been working so hard on this other car I'm building - I need to go back and do some maintenance on my other cars.

Turns out this was much ado about little in the end.

Thanks

 

[Pops1967GTX]

I Glad it work out, post a few pics.....

 

[AR67GTX]

Not a show car but a pretty good driver and cruise in car.

Thanks for the help.

 

[Pops1967GTX]

Nice....another great GTX....

 

[Hemi Rebel]

Wow, awesome car.

 

[440roadrunner]

!!! MAN !!! thas' nice!!!

 

[RustyRatRod]

SUPER nice car. It would not hurt a thing to unplug the firewall connector and put some dielectric grease on the connectors.

 

[AR67GTX]

SUPER nice car. It would not hurt a thing to unplug the firewall connector and put some dielectric grease on the connectors.

I did that about 7 or 8 years ago - unplugged them, brushed everything as best I could with a brass bristle gun brush and lightly coated them with dielectric grease. Since then I've wondered if it is really a good practice to apply it directly to electrical contacts. It's never created a problem for me but it is suppose to be an insulator grease. What do you think?

This time I just unplugged them, looked at them to see they looked clean and plugged them back in.

Thanks for the compliments. It looks a little better in pictures.

Dan

 

[440roadrunner]

Dielectric grease is made exactly for that purpose. The only sort of contacts you really don't want it on is something like a relay which arcs and burns. The whole deal with electrical contacts is PRESSURE.

The big problem with Mopar bulkhead connectors is that those little spade connectors were NEVER designed for the kind of current they must handle. These are also typically used in electric furnaces, where each element (5KW each) draws "about" 20 amps. I used to service HVAC, and had a fair amount of trouble with 'em at 20 amps, so you can imagine trying to poke a 60A alternator through one of 'em.

 

[RustyRatRod]

The absolute best dieelectric grease I have found through the years is made by.......wait for it..............Motorcraft. lol That's some good stuff.

 

[AR67GTX]

Good information - thanks.

 

[dwayne venton]

My 67 GTX hasn't been run in 3 months due to a bad radiator. Finally had it re-cored and installed new water pump. When I finally started it today, the battery spun it over OK. It took 4 primings of the carb and key starts before it filled the carb and kept running so the battery seemed to be doing it's thing.

After I got it running, I engaged the AC and let it idle while I topped off the radiator and sealed everything up. I sat back down inside and noticed the voltage was low - about 10 - 10.5 volts at idle with the AC compressor engaged and fan on high and the dash amp gage was showing discharge. I have voltage and oil pressure gages under the dash. I reved the motor up some but the voltage did not increase hardly any. It typicaly use to run about 14 - 14.5 volts or a little more once above about 1000 rpm falling to maybe 13 at idle with the AC on. I killed it and then re-started it and the starter seemed to turn a little slow so I decided to charge the battery.

I put a battery charger on it for a couple hours (slow charge rate) but although showing close to 100% charge it never did fully charge and go into a float stage. Voltage across the battery posts was about 12.6 V.

I decided to venture down the road in the car and see what it would do. It re-started fine but still had very low voltage. I turned the AC off and the voltage jumped up about 1.5 volts - maybe a little more. Turned the AC back on and the voltage drops back. But even with the AC off the voltage doesn't get back to the 14 - 14.5 volts it ran before. With the AC off the amp gage reads slightly positive but at 50 mph the voltage was only reading about 12.5 to 13. When I got back I killed the motor and it re-started fine.

I've had this car about 10 years and it has the usual rebuilt alternator on it of questionable output. I put a solid state voltage regulator on it when I first bought it and it has seemed to work OK - at least up until now.

How do I best trouble shoot this thing? Electrical is not my strength as beyond knowing enought to not hold a spark plug wire to my tongue - my skills are about tapped out. The shop manual isn't a lot of help as it mostly discusses testing components rather than basic system checks. I'm tempted to put a new rebuilt alternator on it but then I wonder if the voltage regulator has crapped out. And then the high voltage drop when I turn the AC on makes me wonder if the fan motor has about kicked the bucket and is pulling high amps. The battery could be an issue but it seems to be holding up. I'm leaving it on a charger tonight.

I have a decent multigage electrical tester and a few other things like a test light, so I can do some basic checks if anyone has any suggestions. I've read the trick of pulling the positive battery cable with the motor running is not a reliable test of the charging circuit and doesn't help pin-point the problem. I may still have the old mech voltage regulator also that I could re-install, but I will have to look for it.

Another note - I have a green knob battery disconnect on the car and I have problems with it not making a good connection but I assumed that would only cause a starting problem when amp draw was high.

Thanks in advance for any help.

Dan

i had similar probs and a very well known electrical shop jumped a wire from the live connection on alternator direct to batt pos and it gave me some exra amps.for accessories ect. very easy cant hurt to try

 

[RustyRatRod]

Ron Francis is noted for having the best wiring harnesses in the industry. Guess what they eliminate? The firewall connector. That has been the source of more electrical maladies on not just Mopars, but lots of older cars through the years. My friend Calvin put a Ron Francis harness on his Duster and likes it a lot. I've seen it. It's quality stuff. Just food for thought.