alternator problem
jamierojas
12-29-2005, 05:06 PM
I don't know what's wrong with my 1990 pontiac transport.My battery keeps draining.I bought a new battery and a new alternator.I checked the belt it seems good.i pulled the fuse for the compressor about a year ago.I took it in to be tested and they said it was the alternator but i just bought a new one 10 minute before from them.I'm going to take it out and have them check it while it's out of the car.They tell my it's only giving a 12 charge when it should be around 13-15.What else could it be.My wires my fuses?I can't figure it out.
jamierojas
12-29-2005, 05:09 PM
why else is my battery being drain.compressor fuse pulled,new battery and alternator in,belt good.Alternator is charging at a 12 when it should be at13-15
LMP
12-30-2005, 11:18 AM
Check these out:
www.avigex.ca/xport/charging.jpg
www.avigex.ca/xport/starterdiagram.jpg
CONditions for the alternator to charge:
- must be OK...I suspect this is satisfied since you have a new one
- must receive "excitation" voltage: this 12V is fed to the alternator "field" F connection (which is in fact the internal regulator) as soon as you turn the key to ON (engine not need running): is this satisfied? This 12V must be tested on wire at alternator end ;if possible make 2 tests: one connected to alt , one disconnected. Wire must read 12V in both cases.
- "hard" connection from alternator to battery must be existing: there is a fusible link H on this . Should measure 12V on that wire at alternator with key OFF; to ensure no stray voltage goes through a blown link (a voltmeter will read 12V even at an infinitesimal amount of current), connect something with jumpers, like a 12V bulb or small 12v air compressor: it should run full speed (engine not running,key OFF).
Fusible link H connector
www.avigex.ca/xport/fusiblelinkh.jpg
is bolted to the starter solenoid and corrosion at that level can impair charging. WD-40, unbolt, wd-40, and bolt again.
ALl of this from '93 manual but there were very few changes, if any.
Return with these results for further discussion.
Sadly, all of these could have been done before paying huge $ .
www.avigex.ca/xport/charging.jpg
www.avigex.ca/xport/starterdiagram.jpg
CONditions for the alternator to charge:
- must be OK...I suspect this is satisfied since you have a new one
- must receive "excitation" voltage: this 12V is fed to the alternator "field" F connection (which is in fact the internal regulator) as soon as you turn the key to ON (engine not need running): is this satisfied? This 12V must be tested on wire at alternator end ;if possible make 2 tests: one connected to alt , one disconnected. Wire must read 12V in both cases.
- "hard" connection from alternator to battery must be existing: there is a fusible link H on this . Should measure 12V on that wire at alternator with key OFF; to ensure no stray voltage goes through a blown link (a voltmeter will read 12V even at an infinitesimal amount of current), connect something with jumpers, like a 12V bulb or small 12v air compressor: it should run full speed (engine not running,key OFF).
Fusible link H connector
www.avigex.ca/xport/fusiblelinkh.jpg
is bolted to the starter solenoid and corrosion at that level can impair charging. WD-40, unbolt, wd-40, and bolt again.
ALl of this from '93 manual but there were very few changes, if any.
Return with these results for further discussion.
Sadly, all of these could have been done before paying huge $ .
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