AMP Gauge Needle Pointing in Wrong Direction

Stephen Rauch · #1 (**permalink**) 08-26-2003, 08:44 PM

I replaced my alternator. The back of the alternator was close to the engine block so I got some very slight sporadic arching when the engine was running. I quickly turned off the engine and fixed the problem. I noticed now that the needle on my amp gauge now points straight down instead of straight up (reverse where it should be). The needle moves when the engine is running – it is just moving in the down position (again, reverse where it should be).

Question: Did I fry the amp gauge or something else (starter solenoid? Capacitor?) when the alternator was arching against the engine block?

By the way – took the car out for a drive – everything else seems to be working correctly.

Thanks!

KobraKarl · #2 (**permalink**) 08-26-2003, 09:04 PM

One wire alternator?

petek · #3 (**permalink**) 08-26-2003, 09:25 PM

I can't imagine a way of frying an ammeter and get the results that I think you are saying you are getting. Are you saying the ammeter is reading a discharge condition while the engine is running?

trularin · #4 (**permalink**) 08-27-2003, 05:24 AM

probably pegged the meter and now the airpack is out of spec. Try another meter.

It is not uncommon for a meter to get damaged if it is a path for large currents that can be found with a short to ground condition.

Just my $0.02

Stephen Rauch · #5 (**permalink**) 08-27-2003, 03:54 PM

Thanks.

Basically the gauge reads 0 at the 12 o'clock position and +/- 60 amps at the 3:30 and 10:30 position. The needle points at the 6 o'clock position. When teh car is running I see the needle flicker a bit showing that the alternater is charging, but flickering from the 6 o'clock position. Should be at the 12 o'clock position.

GeorgiaSnake · #6 (**permalink**) 08-27-2003, 05:24 PM

My SW gauge was wired backwards from the factory. Go figure

. I suspect you damaged the voltage regulator when it shorted out.

Randy

RallySnake · #7 (**permalink**) 08-27-2003, 05:40 PM

Steve,

Sounds like the needle has twisted on the shaft. Is the gauge new enough to be under warrenty? You will have to get a new one or take it apart to twist the needle back to the starting position. This is NOT easy.

The important question is, did you damage the alternator? Put a voltmeter on the two terminals of the battery. With the engine off, it should be at about 12.5 volts.

Have someone start the car. It should drop to 8 or 10 volts while cranking and then jump up to 14.5 once it starts.

If it's above 14 and below 15 volts while running, your alternator is OK. If not, save yourself a lot of greif and get it fixed. Shorting out like that may have damaged the voltage regulator or the diodes. You can run on the battery for days with a damaged alternator. You will not know it's bad unless you test it or the car's engine quits on the road. This is not a fun thing. Been there, done that!

Paul