low voltage at idle but volts go back up while driving

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Nov 21, 2012 | 03:33 AM

supermini99

Thread Starter

Seasoned Member

Joined: Jul 2011

Posts: 327

Likes: 0

From: WA

Year: 1988

Model: Cherokee

Engine: 4.0

low voltage at idle but volts go back up while driving

Hey guys just a quick question.

What would cause my voltage to drop to 10v at idle but when i start driving it goes up to 10-13 volts..Im stumped..also my engine idles at 300rpm really low im thinking this could be the cause..

88 Cherokee 4.0 non high output (stock)

Nov 21, 2012 | 04:22 AM

freegdr

CF Veteran

Joined: Mar 2010

Posts: 47,923

Likes: 38

From: Broward County Fl.

Year: 1989 xj sport 2dr

Model: Cherokee

Engine: 12 hole bosch Injectors

Sounds like alternators getting ready to die on ya . cs130 is what you have .

Nov 21, 2012 | 04:53 AM

squirrelnw

Member

Joined: Sep 2012

Posts: 170

Likes: 0

From: pacific northwest

Year: 2000

Model: Cherokee

Engine: 4.0

if 10-13 volts is your high mark now your alt is going out. pull it and have it run on a bench and also put a meter on it while on the jeep to make sure its not the gauge. check your belt too, it may be loose

Nov 21, 2012 | 10:55 AM

TheKrazyRaven

Junior Member

Joined: Nov 2012

Posts: 43

Likes: 0

Model: Cherokee

+1 on checking the belt first, if is tight your alt is prob junk.....stick a multimeter on the bat while its on, I'm not sure of the exact spec but anything lower then 13.5-13.8v is suspect