Charging problem
 

Okay, a while back I posted about a wandering tach needle (obvious difference between what my tach reads and the engine revs---either too high or too low).

Right after that happened, I started having charging problems. Charge the battery up with my charger, and it still won't crank. I jump it with my battery jumper box, and it fires right up and runs great.

Poking around under the hood the other day, I found that the Ground wire on the alternator had loosened up quite a bit---not disconnected, but really loose.:eek: I tightened it up, put the charger back on overnight. Next day, it fired once, but would not crank the next time I tried to start it.

I jumped it last night and took it for a 20 minute drive on the freeway in 4th to charge up the battery. Pulled into the garage, shut it off, then tried to start it. Click... Click... Click...

Works fine if I jump it, but when I try to rely on the battery alone, it cannot crank.

I'm going to check the terminal connections on the battery (tucked up behind the rear tire..).

How do I test the battery to determine if I have a bad cell? Would a battery fail within a couple of months of purchase if it had a bad cell? Still under warranty.

Also, that loose ground wire on the alternator: Any possibility the voltage regulator was harmed due to the floating ground? What about the alternator?

DD

Doug - I think the only way to test for a bad cell is to pull the battery and take it down to auto parts store and have them do a load test.

The ground wire on the alternator is really not a factor. It's put there just in case the alternator loses its ground to the engine - not very likely. Since your battery doesn't seem to be charging, the problem is likely to be either a bad connection at the battery or the battery ground, or a bad battery. If you have a cutoff switch behind the seats, check the connections there too.

Where are you connecting your jumper box (when the engine cranks well)?

Doug, are you by any chance runnig a one-wire alternator? I was having similar issues until I replaced my alternator a week or so ago. The internal regulator was on the fritz causing me to have to replace batteries every year to 18 months for the past three years. I had to put a trickle charger on the battery after every major trip so it would start the next time.

Not using the one-wire alternator. Standard issue Mustang alternator.

Bob: I have a Painless solenoid cutoff mounted in the trunk. I pass the power through the panel through insulated panel pass-thru's to the solenoid. When I jump it, I connect to the panel pass-thru for positive, then to the quick-jack rod that extends into the trunk for negative.

I'll try bypassing the solenoid first, then try the battery connections to make sure they are connected well. Then, drag the battery down for a load test, if necessary.

DD

have you checked the alternator? I had one go bad in the mustang and had the same issues.

Haven't checked the alternator yet---I'm working my way up the cost chain.

Battery connections...
Cut-off solenoid...
Regulator...
Alternator...

DD

By the way, if the Alternator went South, wouldn't I see it on the Ammeter?

DD

Could this be an issue with the fused link to the key switch? Does your dash light come on when the key is turned on? My fuse was bad when I first built my car...the engine ran but did not charge the battery. Rob gave me a new fuse and after I replaced it (in the dash light), all was well. It's worth checking out.

Yes, if the alternator is bad, the ammeter should show that the battery needs a charge. Does it show this after you jump the car?

UPDATE: Had some time this evening to pull the battery. More corrosion on the top than I would have expected, having just installed it back in November. Took it down to my local auto parts shop (Winchester), where they tested it. It was "bad", and they gave me a new battery.

Installed the new battery, and fired it up. I haven't had a chance to take it out for a run, but I should tomorrow. Looks like it was the battery.

I may run a check to make sure I don't have any system issues that could cause the battery to fail.

DD

I'm not sure if this applies to your situation or not, but, I was having alternators go bad on a regular basis. I even switched from the Ford to the GM style to no avail. Looking closely at my setup, I noticed that the alternator was fairly close to a header tube. I put a heat shield ( a piece of sheet stainless) between the header tube and the alternator and have had no trouble now for a couple of years.

I noticed on my ammeter today that, after having replaced the battery, it reads slightly higher than it had with the bad battery.

Nice to have my Cobra back, alive and kick'n.

DD

An ammeter should generally read "0" or very close to it as long as the RPM's are up around 2000 or more. If the car is running above 2000 RPMs and you turn your headlights and cooling fan on, the gauge should still read 0. If it's reading a discharge (negative value) of 10 or 20 or 30 amps or so, then your charging system is not working. The only time it should read a significantly positive value is if your battery is drained or partially drained and the charging system is trying to recharge it. If your battery is fully charged and the gauge is still reading a significantly positive value, there's likely something wrong with the voltage regulator.

Chris

My system didn't keep my battery charged (one-wire GM alternator) so I replace it with a new one from a shop in California that winds their own. I purchased a 100 amp unit. Now, my ammeter reads in the positive range all the time and the battery stays fully charged. When I originally did the install, I accidentally pulled the charge wire out of a butt splice and the charge didn't even last long enough for me to make it to work. The car died at an intersection. I had the battery checked (it was OK), had it charged, reconnected the wire and all has been great ever since. I'm running two pusher fans, a 16" puller and a Phoenix Gold stereo power amp.