Damn Alternators, Help

99wjman · 12-14-2006, 10:51 PM

Hey guys its been awhile since ive been on here because ive been away at college but i come home and the heep dosent start, so im like ok battery, then i jump it but the car wont hold an idol. So i have someone sit on the pedal as i look under the hood and i notice the copper core isnt spinning on my alternator. This means its shot right? or does it normally do that. Starter is fine so i think its either that or the battery, alittle help please.

rrubio · 12-14-2006, 10:53 PM

Battery is way being dead.It will no hold a charge at all.New battery and you will be ok..

j.love · 12-14-2006, 11:00 PM

The coper wires inside the alt. don't spin. The magnet inside the wires spins. look deeper inside of the vent holes and you'll see it spinning. The shaft would have to break in order for it to not spin.

check all your battery cables. If there is any kind of corrosion on them it will not run properly. GC's are funny like that! Clean the crap out of the terminals and check the ground wire and try it again and see what happens. look at the leads coming into the battery cable clamp also. could be corroded to the led connector.

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j.love · 12-14-2006, 11:04 PM

Quote:

Originally Posted by rrubio

Battery is way being dead.It will no hold a charge at all.New battery and you will be ok..

Your alternator should be able to run the motor with out the battery. so I would say look down stream from that. Yea the battery could be drained but it should still idle with a dead battery.

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JamesEric · 12-15-2006, 05:18 AM

When you first tried to start it did it just click or did it crank but not start? If it cranked but did not start it sounds like a fuel issue. If holding the gas peddle helped now is a good time to check the fuel pump and fuel line pressure. It could also be your check valve. I have a ZJ so I can't speak about the WJ but the ZJ has a check valve which prevents the fuel from draining back into the tank. If the valve fails the fuel drains back into the tank and you'll need to pump the peddle after the Jeep has been sitting overnight or a few days. If you had a clicking sound and it did not crank have the battery tested. If the battery checks out, examine the wiring for a bad connection and monitor the system to see if something is draining the battery when it is turned off. If you have good fuel pressure and battery, then the next check would be the throttle position sensor, idle air control motor, and other sensors.

greasefingers · 12-15-2006, 05:31 AM

Pull the codes.
Extracting TDC Trouble Diagnostic Codes:
Without starting the engine: cycle the ignition switch ON, OFF, ON, OFF, ON quickly and observe the CHECK ENGINE LIGHT. The CHECK ENGINE LIGHT should begin to flash a series of codes. The flashes will be separated by short and long pauses. The long pauses separate the "ones" and "tens" positions, and each code from the next. A code 55 will be displayed at the end of the test.

99wjman · 12-15-2006, 07:56 PM

yeah i looked at it in the dark last night and was taking a guess. i also think the alternator would run it without the battery and since it was dying i figured it might be that. But sure enough just needed to clean off the corosion and she fired right up. Tahoe here i come. thanks guys

**5-90** · 12-15-2006, 08:34 PM

Quote:

Originally Posted by j.love

Your alternator should be able to run the motor with out the battery. so I would say look down stream from that. Yea the battery could be drained but it should still idle with a dead battery.

.

Nice theory - but sometimes the Chrysler controls (that's what he has) can get silly with a flat battery - even with the alternator giving good output.

Got another battery that you know is good? If it runs with that, then the battery is shot and wants replacing...

5-90

j.love · 12-15-2006, 08:45 PM

Quote:

Originally Posted by 99wjman

yeah i looked at it in the dark last night and was taking a guess. i also think the alternator would run it without the battery and since it was dying i figured it might be that. But sure enough just needed to clean off the corosion and she fired right up. Tahoe here i come. thanks guys

Have fun in Tahoe! you taking a board or two thin sticks?

j.love · 12-15-2006, 08:47 PM

Steve, you fire up that dremmel yet?

.

99wjman · 12-16-2006, 01:27 PM

it was def corrosion on the battery because after i cleaned it up it fired right up no jump or anything

ohh and i aint takin no think sticks im taken an 07 burton custom man

12-15-2006, 07:56 PM	#7
99wjman Registered User Join Date: Dec 2005 Location: Bay Area Posts: 172 Profile Gallery Classifieds My Jeeps	yeah i looked at it in the dark last night and was taking a guess. i also think the alternator would run it without the battery and since it was dying i figured it might be that. But sure enough just needed to clean off the corosion and she fired right up. Tahoe here i come. thanks guys __________________ [FONT="Arial Black"][/FONT]1999 Grand Cherokee Limited 4.7l v8 FIPK 2 91k Bridgestone dueler revos

12-16-2006, 01:27 PM	#11
99wjman Registered User Join Date: Dec 2005 Location: Bay Area Posts: 172 Profile Gallery Classifieds My Jeeps	it was def corrosion on the battery because after i cleaned it up it fired right up no jump or anything ohh and i aint takin no think sticks im taken an 07 burton custom man __________________ [FONT="Arial Black"][/FONT]1999 Grand Cherokee Limited 4.7l v8 FIPK 2 91k Bridgestone dueler revos

12-15-2006, 05:18 AM	#5
JamesEric Registered User Join Date: Jul 2004 Posts: 282 Profile Gallery Classifieds My Jeeps	When you first tried to start it did it just click or did it crank but not start? If it cranked but did not start it sounds like a fuel issue. If holding the gas peddle helped now is a good time to check the fuel pump and fuel line pressure. It could also be your check valve. I have a ZJ so I can't speak about the WJ but the ZJ has a check valve which prevents the fuel from draining back into the tank. If the valve fails the fuel drains back into the tank and you'll need to pump the peddle after the Jeep has been sitting overnight or a few days. If you had a clicking sound and it did not crank have the battery tested. If the battery checks out, examine the wiring for a bad connection and monitor the system to see if something is draining the battery when it is turned off. If you have good fuel pressure and battery, then the next check would be the throttle position sensor, idle air control motor, and other sensors.