PDA

View Full Version : 84 SVO keeps running out of juice.



MIGISMALLS
09-01-2011, 08:41 PM
So my SVO seems to drain its juice after a couple miles of D.D. Figured it might have been my alternator since the battery seem to not be charging at all. I turned on the car (http://www.allfordmustangs.com/forums/#) and pulled the negative battery cable off to check if the alternator was bad or not. The car instantly shut off. Then I checked it with a volt meter and at idle it was at 12.38v. Bought a new alternator and problem still exists :-/ checked the cables and all plugged in good. In the process also replaced the Voltage regulator, Pig tail that goes into it since it was cracking, and battery. Problem still their and don't know what else to check. Any ideas? Thanks in advance for any help.

NotBud
09-02-2011, 10:15 AM
First off - NEVER pull off a battery cable when the car is running. You're very lucky you didn't smoke all the electronics in it.

1. Verify all the charging system cabling first. repair/replace as needed. If it's original cabling, all of it will need to be replaced.

2. By "new alternator" do you mean a reman from a parts store? Have it tested first. If it tests good, then check the alternator output voltage at the output lug terminal on the back of the alternator.

3. If there is no output, then check that the field wire is good (from the regulator) and connected to the inner-most lug where the brushes are.

4. If that's good, run a separate temporary small gauge wire from the battery positive to the field terminal for a few seconds while the voltmeter is still connected to the alternator terminal.

CAUTION: If the cable from the output of the alternator to the battery (or battery side of the starter solenoid) is bad, the alternator outout will climb to several hundred volts - which will destroy the diodes (bad) and possibly kill the operator (worse). So make SURE the alternator-to-battery cable is good.

If the cable is good, & the alternator is good and it is full-fielded, then the battery voltage should climb to 15 VDC quickly (it if has a good charge). DO NOT allow the battery to remain over 15 VDC for more than a few seconds. Trust me on this - you will not like battery acid burns.

5. Repair/replace as needed.

Note that none of this is SVO specific. Just typical alternator / regulator system troubleshooting for externally regulated systems.

dwgray
09-05-2011, 08:55 PM
MIGISMALLS, I'd certainly follow NotBud's advice. The only other consideration would be to ensure BOTH your positive and negative battery cables are in good shape. Sounds silly, but I've encountered battery cables that LOOK good on the outside, but were in bad shape on the inside. NOT suggesting this is the case, simply adding to the sound advice NotBud is providing as GOOD heavy gauge battery cables are easy and inexpensive. I used welding cable from work with lugs and my own battery posts which can be bought anywhere. Good Luck. Doug

NotBud
09-06-2011, 09:07 AM
IMHO - welding cables are indeed a good electrical conductor and, generally, made form a smaller strands of wire making it more flexible than common battery cable.

However the shielding in welding cable is not good for resistance to most automotive fluids & chemicals so be sure to inspect it frequently.

MIGISMALLS
09-07-2011, 05:55 PM
didn't mean to skip your comment bro. I will definitely do that too. though, if do remember correctly from the back of the alternator to the battery it reads 12.48v. and yes it had to be re-man since it was not expensive at all.


First off - NEVER pull off a battery cable when the car is running. You're very lucky you didn't smoke all the electronics in it.

1. Verify all the charging system cabling first. repair/replace as needed. If it's original cabling, all of it will need to be replaced.

2. By "new alternator" do you mean a reman from a parts store? Have it tested first. If it tests good, then check the alternator output voltage at the output lug terminal on the back of the alternator.

3. If there is no output, then check that the field wire is good (from the regulator) and connected to the inner-most lug where the brushes are.

4. If that's good, run a separate temporary small gauge wire from the battery positive to the field terminal for a few seconds while the voltmeter is still connected to the alternator terminal.

CAUTION: If the cable from the output of the alternator to the battery (or battery side of the starter solenoid) is bad, the alternator outout will climb to several hundred volts - which will destroy the diodes (bad) and possibly kill the operator (worse). So make SURE the alternator-to-battery cable is good.

If the cable is good, & the alternator is good and it is full-fielded, then the battery voltage should climb to 15 VDC quickly (it if has a good charge). DO NOT allow the battery to remain over 15 VDC for more than a few seconds. Trust me on this - you will not like battery acid burns.

5. Repair/replace as needed.

Note that none of this is SVO specific. Just typical alternator / regulator system troubleshooting for externally regulated systems.

MIGISMALLS
09-22-2011, 05:05 PM
OK so ups never was able to deliver my alternator kit according to them. So I'm just going to have to go with the 3g conversion. Does anybody know how to go about doing that conversion? Would really appreciate the help. Specially cuz that's all I see at junk yards and can just cut the alternator wires straight from the harness. Thanks again

Mr. Pink
09-23-2011, 03:28 AM
Yeah, check out PA Performance. You can get a new 3G 95amp with new wiring (only one wire to tap into the stock wiring). Personally, a lot better then going to a junkyard and not knowing exactly what you're getting.

http://www.paperformance.com/scripts/prodView.asp?idproduct=46


825

keith84svo
10-02-2011, 04:40 PM
I had the same problem. Mine wouldn't charge the battery and was loosing volt charge. I replace it with a single wire 160 volt and neve had any issues.

NotBud
10-03-2011, 02:49 PM
I replace it with a single wire 160 volt and neve had any issues. I HOPE you meant a 160 AMP unit.

Just sayin'.

MIGISMALLS
10-03-2011, 08:58 PM
yea, i ended up redoing all the wiring from the harness to the alt. after going into the harness i saw that it was burnt. after replacing the wires with new ones, it charges right up. helped me to save money for a 3G set up down the line.

keith84svo
10-05-2011, 03:08 PM
Yes 160 amp. all you need to do is hook up the power (red wire I think) to the alternator and hide all the other wires.

Mr. Pink
10-05-2011, 03:28 PM
Keith...are you sure that's the only wire you have to hook-up? I just installed a PA Performance 95amp and besides the power wire to the starter solenoid, I had to tap one wire into the factory voltage regulator harness.

keith84svo
10-05-2011, 03:50 PM
The one I have is Its a 1 wire power source. I disconnected the volt regulator.Everything is internal. bought it new from alternator shop down the street with the addition of swapping the pully for $140.00. When you open the hood , thats the 1st thing you see. Would you like me to post a pic.

NotBud
10-05-2011, 05:33 PM
Keith...are you sure that's the only wire you have to hook-up? I just installed a PA Performance 95amp and besides the power wire to the starter solenoid, I had to tap one wire into the factory voltage regulator harness. If you use the factory regulator, you need an additional wire from the factory regulator to the internal regulator as a voltage reference source.

If you DO NOT use the factory regulator, then the internal regulator will sense the output line for battery voltage.

keith84svo
10-05-2011, 06:16 PM
here is the only problem. The owner before me hook the fan up with some speaker wire for a manaul switch. The fuse keeps blowing. I increased the fuse by 5 and it still blows. Any ideas on fixing it. I think I might have to switch it back to factory connection.

NotBud
10-06-2011, 12:22 PM
Depending on what kind of speaker wire, it might need replacement.

Measure the actual voltage at the fan motor connector with the fan on. if it's less than 1/2 volt below the battery voltage, increase the wire size.

Next measure the current draw of the fan motor (you will need a special tool for this as most hand-held VOM meters will not mearure high current levels). If it's over 15Amps running, replace it. Start-up current is typically double running current.

Mr. Pink
10-06-2011, 06:08 PM
Yeah...I'm running a 3G alternator.....one power wire and one wire into the voltage regulator harness....the connector kit I got from PA Performance called for tapping into an "Ignition On" point....I used the diagram I posted earlier in this thread as a reference.....

4themasses
01-01-2012, 11:32 AM
I'm in the same situation. Where did you find a new pigtail? Mine looks bad where the alt. wring plugs into the factory harness. Replace alt, volt reg. and a new batt. and barely goes above 12 volts while runnng.

Update: I see Forced4 has a replacement pigtail for about $50.

MIGISMALLS
01-01-2012, 07:32 PM
I was able to salvage the pigtail. In my situation, it turned out that somehow the wires were on backwards when I replaced the regular and it burned that out so just replaced it and wired up correctly and haven't had a problem since. though I did get them pigtails before from foxes at the junkyard

NotBud
01-01-2012, 08:49 PM
Most autoparts stores will either have that stock alternator harness or be able to order it but the real issue is that it's a 10 gauge wire which is rated for about 30 Amps continuous. And the stock alternator is rated to 65A, so the harness, cable and connector rated for 30Amps doesn't last very long.

Might as well replace it with a properly gauged cable (with fuse) so you won't ever have the problem again.

Engine electronics needs about 8 Amps to run. Stock radio uses about 5 Amps at full power. Rear defogger uses 20 Amps, new cooling fan uses ~12Amps, 20 when it's old. Stock headlighs/taillights use about 15 Amps, halogen replacements with fogs on adds another 10. And about 8 Amps per electric window operating until it reaches a hard stop where it uses about 25 amps. AC adds another 8 (plus the cooling fan values).

So it's real easy to see how that 30Amp harness rating can be easily exceeded. A 95 or 130 A 3G makes the problem MUCH worse very fast.

4themasses
01-02-2012, 06:28 PM
So it's real easy to see how that 30Amp harness rating can be easily exceeded. A 95 or 130 A 3G makes the problem MUCH worse very fast.

Thankd for that last bit of info. I'm reading where alot of Mustnag owners are going to this 3 G setup.

Do you think the alternator harness from Forced 4 would be a ideal replacement? I'm gonna go over the ground connections as well when I get the chance.

NotBud
01-03-2012, 09:23 AM
The harness/cable from Forced4 is the one from Pat Pearson, aka PatInLA (PLA) fame. That's a very heavy charging cable with a fuse in-line. So, Yes, that will work.

MIGISMALLS
01-07-2012, 01:43 PM
Yeah I need to get mine before I put anything that will drain more juice from it.

4themasses
01-07-2012, 02:26 PM
Just to follow up:
My AMP light was not coming on. Replaced bulbs AND cleaned contacts on back of cluster and that did the trick. I have 14.5V now.