Amp meter reading?? Am i charging? (1 Viewer)

[jbee]

See photos below. 74 FJ40 FST, stock engine.
Engine running at idle. Reading low is with headlights on, reading in the middle is with lights and everything else off. Also a couple photos of my alternator.
Is this thing charging? Need to drive it to the club meeting tomorrow!!

 

[shelfboy1]

is the belt tight looks like you need a new one,your not going to make the meeting unless you fix your truck or the wires on the amp gauge were switched.+ charge - discharge.

 

[dancar]

From the meter, I'd say no, but we know that not all meters are accurate.

Easiest way to check is to put a multimeter across the battery when the engine is off - should be ~12V

Turn the engine over, should drop down (not less then 10V) and then when running, the battery should be at 13-14V

 

[DSRTRDR]

were you driving or parked when you took the pic - does the needle go into the middle when you rev it up ?

of course, you should drive to the meet - that's where the experts are

 

[Rocky_LC]

Buy a cigarette lighter Volt Meter at Pep Boys for $10, or on eBay for cheaper.... and know for sure.

 

[inkpot]

Drive it to your nearest auto parts store. Most do a battery check for free. They can test it for you. John

 

[jbee]

Thanks for the help. I'll check the things mentioned here. Photo was taken with car running at idle. Revving engine has no effect on the gauge reading.
I drive it 80+ miles last Sunday, did not kill the battery, but it was daylight. Also, it sat for 2+ weeks before that and started right up so I'm thinking the battery is ok. I'm hoping bad or weak or inaccurate gauge.
I ordered a Sunpro 3 gauge set and new temp and oil sending units; hopefully I'll get some more accurate readings.

 

[jbee]

At rest, key off and out, battery reading 12V.

Engine at idle, accessories all off (I only have fan and lights) off, 12V at battery terminals.

Headlights on, engine idling, 11.8 volts at battery.

During cranking, battery drops to 10.8V.

I have a spare alternator I'm going to have checked, I'll also check belt tension and/or replace.

 

[JohnnyC]

whats the volts when idle is up?

yeah alternator check time.... also check all the connectors for corrosion and grounds cleanup

had you ever changed the VR?

 

[jbee]

Have not checked the VR, does 74 have external one?
I'll check the idle up voltage.

 

[JohnnyC]

Have not checked the VR, does 74 have external one?
.

-yes-

on firewall

 

[jbee]

Update:

Changed alternator to used one that tested good. Replaced VR with one off my shelf, might be good. Result is ZERO change in ammeter readings from OP.

Attached new sunpro volt gauge. See photos below. Photo 1, engine off, key off (hooked gauge to headlight circuit for testing).
Photo 2, engine at idle, headlights off.
Photo 3, engine at idle, headlights on.
Revving engine has no effect on gauge reading.

Same question, am I charging?

Where should this gauge read?

 

[dancar]

Update:

Where should this gauge read?

If your alternator is charging, then you would expect to see 13-14v on the volt meter when the engine is running.

The increase in voltage trickle feeds the battery - in turn charging the battery.

You ammeter is indicating that the accessories (headlights etc) are drawing current from the battery.

Dan

 

[Coolerman]

Did you check your charge fuse?

 

[JohnnyC]

Did you check your charge fuse?

if his is a 74' I'm pretty sure he has an ignition fuse (like my rig) ... think the engine fuse was in 75'

Did you check all the connectors and wires going into the connectors? clean grounds?

 

[Coolerman]

I meant the fusible link, but then realized it's showing discharge so the link must be good. According to my schematic, the regulator IG terminal is fused via the turn signal fuse. Check that.

 

[Steamer]

I would check the voltage at these 3 points.

 

[jbee]

Monkeyed with the fuse box, used some sand paper to clean things up a little. Now the horn works. All fuses and fuse contacts are clean.

Installed a *new* voltage regulator, sanded a little to get a good ground connection. Still no change at ammeter, reading a little below half at idle and down to 1/4 with lights on. (same thing)

Is this little condenser thingy necessary? (see photo) Could it be an issue? It has a toyota part number on it but it says it's for an old corolla.

I read somewhere here on the board that a battery at 11.8V is a dead one? But, this one reads there and cranks and starts every time? weird.

I'm going to check voltage per the picture posted, that's a great diagram. Also going to check the battery grounds, starter wire, etc. So often its the little things like loose ground strap bolts, etc.
thanks again for the input.
Coolerman, used some of your left over wires to wire the new gauges.

 

[jbee]

JohnnyC and Coolerman FTW!!

Decided to break the bank and change ALL of the fuses even though none of them showed that they were popped. Ammeter is back in business, and my hazards and blinkers even work.
I even had a spare battery on the charger to make it to the meet up tonight...
Thanks again for all the help!

 

[JohnVee]

JohnnyC and Coolerman FTW!!

Decided to break the bank and change ALL of the fuses even though none of them showed that they were popped. Ammeter is back in business, and my hazards and blinkers even work.
I even had a spare battery on the charger to make it to the meet up tonight...
Thanks again for all the help!

Bad fuses that look good and even still pass current has happened to me, too. Now it's just one thing troubleshooting thing to do. I suppose it happens due to vibration.

--john