Charging issues

[handywipe]

I have a 1971 f-100 with a 390 and a 3-spd.I resently installed a new alternator and voltage regulator .The problem im have is it still wont charge.... i dont know what went wrong i went through the diagram and all the wires are correct... can someone help me

[hardtailjohn]

Electrical can be a real bugger!!! I'd start with making sure all the grounds are good, then isolate each part and test it as best as I could. One thing I do know... if you're waiting for your ammeter in the dash to show a big charge, you're gonna be waiting a long time, unless you installed a welder under there!! I'm not sure what amperage it takes to move that needle, but it's a bunch!
Keep us posted and someone somehow might be able to help..
John H.

[jor]

Hardtail is correct; that dash ammeter won't tell you much. Put a voltmeter across the battery with the engine running. You should see around 14 volts.
jor

[handywipe]

i no not to go by the one in the dash if i was told correctly when i bought the truck it wasnt working..... i've went across the battery terminals but still have had no luck... I have installed new battery cables so i guess im gonna re-wire it i dont know this thing is drivin me crazy thanks

[hardtailjohn]

Ammeters need to be in series (or parallel with a shunt), voltmeters usually are in parallel.. just a thought....
John H.

[FORDification]

Some of the easier things to check that come to mind are:

Make sure the battery cables/clamps and belt clean and tight. They might look good enough at a quick glance, but check 'em again, just to eliminate them as a possibility.

Make sure your voltage regulator is making a good ground. Remove the bolts holding it to the inner fender and clean the mounting areas on the back and on the fenderwell. If there's any corrosion in there and the regulator doesn't have a good ground, it'll cause problems.

On Ford vehicles the negative battery cable is connected to the block. Since the engine is insulated from the body by rubber insulation mounts, it must be grounded to the body via a ground strap between the cylinder head and firewall. Make sure it's there and not loose, and that it's making a good connection.

Those are the simpler things to check. However, more than likely it's either your alternator or voltage regulator. Just because they were recently replaced doesn't mean they're still good....or were even good in the first place. Either you might have gotton a bad part or there are other gremlins lurking in your charging system that caused one or the other to go bad again. However, I'd go ahead and double-check the things I mentioned above, and if it's still won't charge, I'd go ahead and take your alternator into the local auto parts store and have them check it out for you, since most will check alternators free of charge.

It just so happens that I'm in the middle of writing up a good tutorial on tracking down charging problems, with a lot more in-depth troubleshooting procedures, but it's not quite finished and is a multiple-page article anyway (too long to post here). I'll be working on it some more tonight and might have it finished and posted. If so I'll let you know so you can check it out.

Good luck!

[oldschoolrods]

On Ford vehicles the negative battery cable is connected to the block. Since the engine is insulated from the body by rubber insulation mounts, it must be grounded to the body via a ground strap between the cylinder head and firewall. Make sure it's there and not loose, and that it's making a good connection.

hey keith do you have any pictures of where its usually grounded, I never noticed that on my truck....

[FORDification]

I don't have a picture of the actual strap, but I CAN show you about where it's supposed to be attached to the firewall. Here's a shot of one of my parts trucks taken right after removing the engine. The yellow arrow points to where the engine ground strap was attached to the firewall....the other end should be connected to the rear of the cylinder head.



If your engine was ever removed by a previous owner it's entirely possible the ground strap was never replaced....since it IS an easy thing to overlook. It being MIA could cause some intermittent electrical problems as the electrical current finds the path of least resistance back to the battery...which could be things like throttle linkage, choke cables, etc.

[oldschoolrods]

I'll have to check it out, if its missing can I just make one out of some 10ga and terminals? Thanks keith

[FORDification]

Well, it would probably be better than nothing, but you might want it a bit heavier than that....normally the ground strap is more of a braided copper or steel strap than a wire. Something like this:

[FORDification]

OK, I just got the new tutorial posted. I plan to add more to this in the new future, but I think for now it covers all the basics. Go ahead and read through it and let me know what you think and if there's anything I need to add.

Charging System Troubleshooting

[oldschoolrods]

Thanks keith, I'll have to check it out if I ever get the thing running again...see post in engine forum for THAT issue.

[jor]

AutoZone stocks ground straps.
jor

[handywipe]

ok so i took the alternator to the auto parts store and the regulator and had them tested... Both Checked out fine so i still have no idea where im going wrong... anymore help guys im at a road block

[heep70]

Is your alt recieving 12v to excite it? Do this test. This is from Keith's "Charging system troubleshooting tutrial".

Keith correct me if I am wrong here, but I think the key needs to be left on without the engine running for this test?

"Shut the engine off and leave the meter set for the 12V range. Touch the heavy (BATTERY or BAT) lead at the rear of the alternator with the positive probe. Using a quality engine ground for the negative probe, again read available voltage at the alternator. This should be approximately the same as the battery's voltage reading.

If you cannot read voltage here, a wiring or fusible link problem exists. Zero the meter and set for DC and K-Ohms. Check the wire from the starter solenoid to the BAT connection on the alternator for continuity and conductivity by holding a probe at each end of the wire. If no opens or shorts exist, the meter will rest happily at the zero line. If there is too much resistance, as with a slight open in the lead or a poor connection, the needle will read upward on the scale. An actual open in the wire prevents the needle from registering at all. Resistance readings help locate corrosion within wire leads, too. Battery cables or terminal clamp connections often develop such problems. Unseen in a visual inspection, a current blockage cannot fool your ohmmeter. The force necessary to keep current flowing is measurable."