Jag x-type 2002 Denso alternator, two year old battery. two occasions a month apart. 85+F. Car stopped for 45 min first time, 15 min secondtime. Restart, no charge. came home, restarted next day car runs normally. Drove car on 100+mile trip, normal. any suggestions on what’s up?


Since the title of this post is charging, you are assuming the charging system is defective?

Has anyone tested the charging system?

Has anyone tested the battery? 2 years old is no guarantee it’s still good

Are your battery terminals and cables heavily corroded?

Has anyone performed a fuel pressure test?

Check engine light on? If so, let us know what the codes are

Could be a bad crank sensor . . .

Lucas, The Prince Of Darkness…

90% of the time, this kind of stuff turns out to be a bad connection someplace…

Most systems require that the warning light turns on when you turn the ignition switch to the RUN position. This supplies power to the exciter of the alternator which gets the field going inside it. The alternator puts a ground on that lead until it gets going then the field puts a voltage on the lead and turns off the light until something happens to it.

If the engine just died on you while driving then you need to check the power connections between the battery and the ignition switch, including the ignition switch itself. There is most likely a fuse panel under the hood that is between the battery and the ignition switch.

In the intrest of brevity, you have made your problem hard to understand.
Did your car stop while running? What do you mean, no charge? If you mean it wasn’t charging when you got it restarted did you base that on a gauge reading or an idiot light?What happened when you tried to restart after it quit? Nothing?
Clicking? Slow cranking? Normal cranking but no start?

Excuse the brevity. I will try to clarify.
The symptom has happened three times in the last month and a half.
First a correction. The car is equipped with a manual transmission. Thus the car comes with a Bosch not Denso alternator.
1st time. A day in the 90’s. Drove about 10 miles with a few shopping stops. I then went to a library for about a half hour. When I started the car, the alternator light stayed on. I drove home, parked the car. Two days later, I started the car and it was normal. V.O.M. check at 13.8V
A month or so later, similar symptoms. Shopping, stopped for 10 min, restarted, light on. Next day, normal again.
Two weeks later, my wife drove about three blocks, returned home because the alternator warning light had come on. I got the V.O.M. and by the time I removed the battery cover and started the car, it was normal. 13.8V.
I now have the V.O.M. on “standby” for the next time. I won’t stop the engine until I get a reading.
I have since driven the car at least 500 miles without incidence.

Sounds to me like the alternator’s days are numbered.

Worn brushes would cause intermittant charging. Worn brushes are entirely possible on a 12-y.o. car, if it’s been driven regularly.

If and when you remove the alternator, check the brushes. If one is shiny where it contacts the slip rings, and the other is (mostly) dull, thete’s your culprit.

Do you notice corroboration that voltage is actually lower when the alt light is on? (i.e. do the lights dim, fan speed lower, etc?)