jeepxj99

The past few days it seems my 99 xj has had some lag trying to start up. When it starts its fine though. Runs good and all. The first day it started doing it, I had it checked at the place i purchased the battery from and it read 100 percent charge. I had left it running for a good 30 minutes before driving the 15 miles to the store though. It cranked fine when I got there and whole charging system checked out fine. Today I didn't crank it until about 3 pm and it lagged horribly, so i took it straight to the store and the alternator checked fine, but this time the battery was only 89 percent and they said that that was okay??? Doesn't sound like the battery is keeping a charge to me? Any Ideas?

ZINGGG

Clean ALL grounds as well as your battery terminals. Some fine sand paper may come in handy doing this. That'd be a good place to start.

RTorrez1

^^ This ^^
Make sure you clean ALL the grounding points and not just the battery.

91 limited owner

How old is the battery? Most of them only last about 5 years.

sycoglitch

Other than cleaning the grounds make sure there is a good copper to clamp connection at the terminal. Good grounds mean nothing if that wire is loose. You should also cut back and redo the copper under the battery clamps.

This happen to me months ago, cleaned all ground, alternator was good but battery kept draining. Went to wrenching on her and found out my positive wire was loose due to the. Item I had on the clamp at the time. Made the bolts come loose. Good luck

Gee oh Dee

When you say it lagged...whatdo you mean? Thats not very descriptive.

Are you saying the motor was slowly cranking? Or it took several cycles of cranking for the motor to fire?

jeepxj99

Motor cranked slowly. Like there was very little power.for.the motor to turn over. And the battery is only 2 years old and still under warranty and my alternator is only 2 months old