Charging System Prob

[MXD]

Hey guys, i have a 1990 Talon TSI with a charging problem. The battery is in the trunk and with the engine off the voltage is 11.48 Volts. When i start it up, it drops down to 11.19 Volts and wont go above that. Now the alternator is new and so is the battery. I have properly grounded the alternator and the battery fuse and alternator fuse are good. I checked continuity from the Battery+ wire from the alternator to the fuse box and its good. Now my question is... Is the Alternator RELAY known to be faulty in these cars and cause this problem? Because when i jumped the two pins on the relay, voltage popped up slightly to 11.57 Volts. Can anyone help please??? Im desperate.

 

[hopeformylife]

I don't claim to be an electrical expert by any meens, but what guage of wire did you use to run from the battery? My thought was to small of wire may not allow for enough voltage - but it's just a thought.

EDIT: Sorry I didn't really address any of your questions directly.

 

[Eclipsethis90]

Your alternator (if properly working) should be putting out more than 11.XX volts, and more in the range of 13-14v. What gauge wire did you use for negative and positive?

 

[MXD]

I used 2 gauge wire from the engine compartment to the back. I tested power and ground circuit at the engine compartment before they go all the way to the back and there too is 11.19 Volts. Thanks though guys for responding

 

[snox135]

It's been a long time since I've checked voltage on a alternator. But I'm pretty sure our alternators don't have 100% output at idle. Try reving the motor to 2k or higher and check the voltage.

What problems are you seeing with the car to make you check the voltages?

 

[Newlogics]

Just beacuse your alternator is new, doesn't mean it's good. Take it out and have it tested at autoparts store. I've dealt with amazing number of bad alternators straight from the shelf.

 

[MXD]

It's been a long time since I've checked voltage on a alternator. But I'm pretty sure our alternators don't have 100% output at idle. Try reving the motor to 2k or higher and check the voltage.

What problems are you seeing with the car to make you check the voltages?

Im not seeing any problems with the car to make me check it. I acquired the car in non-running condition due to a bad timing belt. The car runs fantastic (No suspension so i cant drive it) and all, but i just relocated the battery and installed a new alternator and checked it for the hell of it, and thats when this came up. I know i relocated the battery correctly and all, but the only thing i haven't tried yet is the alternator relay. Thats why i wanted to know if it went bad often or if anyone has had a similar problem.

 

[MXD]

Oh and when i put apply a voltmeter to the Battery + terminal coming out of the alternator and ground, i get a read out of 14.5 - 15.0 Volts. Whats going on?

 

[Newlogics]

Oh and when i put apply a voltmeter to the Battery + terminal coming out of the alternator and ground, i get a read out of 14.5 - 15.0 Volts. Whats going on?

Well, that changes things.
It obviously indicates that alternator is working.
The only thing in between the alternator and the battery is a 60amp fuse (black, in the corner if the fuse box). If that's fried, then no charge will be getting to the battery.

 

[MXD]

Well, that changes things.
It obviously indicates that alternator is working.
The only thing in between the alternator and the battery is a 60amp fuse (black, in the corner if the fuse box). If that's fried, then no charge will be getting to the battery.

Yeah i checked continuity between the terminals of that fuse too and that too is good. Weird huh? and frustrating too.

 

[MXD]

Does anyone have wiring schematics for the charging system that they can post up? That would be a great help...

 

[Newlogics]

Does anyone have wiring schematics for the charging system that they can post up? That would be a great help...

Directly from factory manual:
OPERATION
When engine is stopped
When the ignition switch is switched to the "CN"
position, electricity flows from the "L" terminal, of the
alternator to the field coil, and at the same time the
charging warning light illuminates.
When engine is being started/has started"
When the engine is started, charging voltage is
applied to the "L" terminal of the alternator, with the
result that the charging warning light is extinguished.
In addition, because battery voltage is applied to the
"S" terminal of the alternator, this battery voltage is
monitored at the IC voltage regulator, thus switching
ON and OFF the current to the field coil and thereby
controlling the amount of generation by the
alternator.
Power is supplied to each load from the "6" terminal
of the alternator.
NOTE
The alternator relay functions as a back-up for the
flow of electricity to the field coil if there is a
disconnection or damaged wiring of the charging
warning light.
TROUBLESHOOTING HINTS
1. Charging indicator light does not go on when the
ignition switch is turned to "ON", before the
engine starts.
l Check the bulb
2. Charging indicator light fails to go off once the
engine starts.
Check the IC voltage regulator (located within
the alternator).
3. Discharged or overcharged battery.
Check the IC voltage regulator (located within
the alternator).
4. The charging warning light illuminates dimly.
Check the diode (within the combination
meter) for a short-circuit.

If you need any other info from manual, let me know.

 

[MXD]

Thanks for the diagram Newlogics im sure it will come to use soon. Anyone else know of any common wiring issues that may cause this problem? Thanks...

 

[UnlshdEclipse]

this sounds crazy but, are the terminals on the batter are clean as well as the battery cable connections?

 

[MXD]

yeah they are. Its a brand new battery, cables, and cable ends. Everything is fresh at the battery

 

[MXD]

Well guys i found the little critter giving me the problem... It turns out the wiring from the fuse box to the battery was damaged. Thanks to Newlogics for the wiring info which turned out to help a lot!! Thanks to all of you for your imput...

 

[silvercoupe97]

That's some good info Paul. I'll have to bookmark this when I troubleshoot my "no charge" issue.

...and MXD...."iNput"

 

[MXD]

That's some good info Paul. I'll have to bookmark this when I troubleshoot my "no charge" issue.

...and MXD...."iNput"

Thanks Slick... haha

 

[silvercoupe97]

Bah, I'm going to buy a rewired 110amp alt. I've got a feeling that my regulator is dead since it won't charge my new battery, but it will keep my car running.