huntsman

Ok so Iv been getting the check guage light and the voltage on the guage drops to 9v and this happens randomly. So I cleaned all the grounds today, and checked my battery, its at 12.5v so thats about right. Now when i turn the jeep on and its idling I get 13.58v is that ok? I thought it was suppose to be around 14.2 - 14.7v when the car is on. 13.58v seems a little low and thats with nothing on, no headlights, no radio, no fan/ac, so If i turn those things on itl drop a few more.

Hmm let me know what you guys think, as I dont want to go taking the alternator out if 13.58v is alright.

DFlintstone

13.6 right off the battery with a DVM seems a bit low. One of my 90's idles over 14 with high blower and brights. A real meter right on the battery is a good start. The dash gauge is just a maybe reference.

quneur

I'm assuming its a 1998. How many miles? 13.8 is still charging the battery but it sounds like things are wearing out. I would do a quick check on belt condition and tension. You are going to have to do it anyway when taking out alternator. I suspect the alternator brushes as being worn.

bryanintowson

It sounds like your alternator is starting to get worn as quneur suggested as long as you verified those readings with your multimeter.

I was worried that my alternator was failing because the gauge cluster on my 92 was showing 9v under load and 12-13 at idle.

I checked it with my multimeter and it showed 12.6 when off, and 14 at idle.

Turns out the gauge was a liar and according to some forum posts I've read, the volt meter on the pre-97 gauge cluster are notorious liars.

Jeep Driver

I would not be overly concerned, keep and eye on it though.

Fred/N0AZZ

13.8 at idle is about normal without a load.

ehall

13.8 is fine for summer temperatures

sycoglitch

Specially summer months. According to the guage im at 13.5-13.75 during the summer and winter its a lil past 14. The temp sensor below battery has a lot to do with it iirc.

huntsman

Alright thanks guys, just wanted to double check with everyone and yes its a 98 xj with 154k miles I cleaned out all the grounds and nothing showed up yesterday but got the check gauge light on again today. Yes I used a multimeter to read the voltage. I was a lil concerned as I will be going to michigan next week which is like a 6-7hr drive one way. I dont want to get stuck somewhere haha. But yes its also summer here been around 80-90 degrees and humid.

huntsman

what brand alternator do you guys recommend ? I was thinking bosch or denso when I decide to change it.

Squid

Whenever I need an alternator I go to a specialty shop that rebuilds mine. Much cheaper than a new OEM . One day turnaround unless he has one on the shelf then it's a swap. Stay away from the auto parts store aftermarket junk.

Crash_Course

Rebuild is certainly an option especially if you know a good shop.

Buying a replacement, I try to stick to national brands like AC Delco, Bosch, Nippondenso, etc... but I avoid reman units like the plague. Burned too many times by remanufactured parts.