1987 Charging Problem

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1987 Charging Problem

July 21, 2011, 05:52:14 PM

I have a 1987 Cougar 5.0 with an electrical/charging problem. There are three symptoms that I assume are related: A repeatedly dead battery, a low voltmeter (I have the digital gauge and the reading is one bar below normal, within the acceptable range but low enough to trigger the warning chime), and a VERY slow turn signal. I am talking like 2+ seconds per blink.

I changed the battery but that didn't help. Then I took it to O'Reilly (where I bought the alternator several years ago) and had them test the alternator. They said it was reading low (about 13) so they would replace it under warranty. But the remanufactured one they gave me didn't get rid of the low voltmeter reading or the slow blinker.

So is my next step to change the wiring connectors to the alternator, or is there something else I should try first?

Thanks in advance for any input!

Nathan

1987 Charging Problem

Reply #1 – July 21, 2011, 09:19:16 PM

Measure the charging voltage at 1100 RPM with a moderate load at the battery lugs. It should be 14.0-14.6. This will confirm a good alternator to some extent. Measure the voltage and post back. If the voltage is low at the battery take a reading at the alternator heavy lug. If the voltage is higher and close to the numbers above you have a voltage drop. Do some testing and post back. Good luck

Note make sure the belt is ok and has the right tension.

1987 Charging Problem

Reply #2 – July 22, 2011, 12:44:25 PM

Make sure the ground cable from the engine to frame is tight. Also, make sure the Neg battery cable connections are tight and there is no corrosion (look for green corrosion in the battery cables, if they are originals).

1987 Charging Problem

Reply #3 – July 22, 2011, 07:09:35 PM

Good connections are a must . Plain and simple. That can be tested with a voltage drop method. It should be dun on the grounds and the battery feeds as well

1987 Charging Problem

Reply #4 – August 02, 2011, 07:18:34 PM

Well I had suspected the belt, so I replaced it because it needed it anyway. As far as I know, it was the original one, which would mean it had 24 years and 188,000 miles on it. But that didn't help the problem.

I don't have a voltage meter, so I haven't checked that out yet. I guess I will have to take it back to O'Reilly or Advance to see what they will do.

There is some green corrosion, but not a lot, inside the negative battery cable near the end. I didn't tear off the sheathing to trace it down, but it seems like it might not run the length of the cable. Could that really be enough cause a problem like this?

Also, the slow turn signals weren't related to my main problem. I replaced the flasher and now they work just fine.

Thanks again for the help.

1987 Charging Problem

Reply #5 – August 08, 2011, 09:56:57 PM

So this is probably a dumb question, but how do I measure the voltage at the alternator? My alternator doesn't have bolts, it has plastic plugs. So where do you attach the meter?