• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Alternator issues HELP!

GudaXJ

NAXJA Forum User
Location
Richmond, Va
It's been a while since I've been on here, especially since I sold my XJ about six years ago. Miss you guys!

This problem has to do with my room mate's XJ. I tried searching the forum for similar symptoms, but couldn't find any commonality or related models.

The heep: 97 XJ 4.0 Auto 4wd 160,xxx ABS stock and not wheeled

The problem: Starting earlier this year while driving check gauges came on and noticed the voltage meter was reading 0. Weird.. ok so we replace the alternator and charge the battery.. everything good.

About a week later same thing.. dead battery and dead alternator.

For good measure we go with a tested alternator under warranty from advance and go ahead and buy a new battery, just to make sure dead cells or a bad battery wasn't the culprit.

Fast forward at least 5 months.. same issues.

Got the alternator tested and it's putting out below 11v.

Other possible related problems: ABS light is on.
After searching google for a bit, I found on an infinity J30 forum that this person was having the same problem and it was actually due to a bad ABS relay draining the battery.


Any thoughts would be greatly appreciated!
 
Well, an alternator that puts out only 11 volts is sick, and I mean that not in a good way.

The PCM regulated alternators--such as the 97 has--are hard for the "box" auto stores to test correctly, and most of the remans they push across the counter are, shall we say, unreliable.

So, here is what you should do:

1. Fully charge the battery and have it load tested with a carbon-pile load tester.

2. If the battery passes, install it in the vehicle with BOTH ends of BOTH cables cleaned and tightened.

3. Measure the static voltage--engine off--between the terminals. Should be about 12.5 volts. Now, start the engine and measure again, should be 13.5 volts to 15.5 volts (it will depend on the battery's state of charge and the ambient temperature).

4. If the alternator is charging--giving your 13.5 to 15.5 volts with the engine running, then check for PARASITIC DRAWS. There is always going to be a SMALL draw on the battery--the memories for the PCM and the radio presets--but if the PARASITIC DRAW is too much it will drain the battery. Check for excessive draws with a multimeter, or if you don't have access you can use a 12 volt test light or small bulb. Using a multimeter to measure the miliamps the draw should be under 25 miliamps, if using a test light or bulb it should only glow DIMLY, not bright.

5. Note that there is a temperature sensor under the battery that will have an effect on charging.
 
Back
Top