I got the dreaded "Battery Not Charging" warning today on the way home.

Voltage was dropping as I raced the 17 miles home at max vacuum (to lessen load on fuel pump), didn't run the wipers (in a light rain) and shut off the radio. The volt gage hit the peg about 1/2 mile from the house and I said "I'm walking", but then miraculously went up to 13 V for the final 1/4 mile.

On a 1997, what is the first thing to look at? New alternator? Voltage regulator? Is there a fuse that blows and prevents charging?

Once the battery is back up to charge, I'm going to test the alternator.

 

Hi Ungn,
250+ views and nobody wants to talk to you?

The +B line to the regulator is fed by Fuse #5 in the engine compartment fusebox. This also powers starter & fuel injection relays, etc. so you'd know if it had blown.

Alternator/regulator is a good place to start. Check continuity of the White/pink wire from the fuse through to the alternator if you can as there appear to be intermediate connectors. Getting to the plug on the back of the alternator while it's still in place is a bit of a bear.

HTH,
Mike

 

Ungn, don't let the number of views discourage most are just looking for answers like you. So let's try somethings before condemning and ripping out the alternator. Jaguars just do not like low voltages they are power hungry cats. I have also learned they do not fix themselves.
1. Remove the battery and have it load tested. A battery with a cell going bad won't take the charge from the alternator. Visually check to see that the hold clamp for the battery is not distorted and stressing the battery casing.
2. While the battery is out thoroughly clean the connections, and remove and clean the ground cable to the body.
3. Follow the end of the positive cable and make sure the connections are clean and tight.
4. Under the bonnet is the connection for the cable from the boot to the engine compartment. Make sure it is clean and tight.
5. Finally at the alternator check that the connections are clean and tight. I have experienced loss and restoration of power due to loose connections.
6. Once all that is done reinstall the battery if it tested good and check to make sure the battery sitting connected is between 12.6 and 13 volts.
7. Start the car and with a multi-meter check the readings across the battery are from 13 to 14 volts. Don't rely on the dash gauge, use a multi-meter. It would help to have someone else start the car. The battery voltage will drop during starting and the alternator will hit max trying to bring it back to proper voltage.
If after all of the testing and cleaning you are getting less than 13 volts it would be time to address the alternator.

Good Luck and keep us posted.

 

Thanks, guys.

The battery is marginal at 12.59V, but I ran an alternator test and my charger said "fault". The Junkyard has alternators for $30 and the weather will be great this weekend, so I'll miata over and snag one Saturday morning.

I figured I'd practice removal on my car to see what tools to bring.

Getting to the alternator was easy. But a big FAIL to the jag engineer that spec'd a tiny 10mm bolt to hold the alternator in place. Waht really sucks is all of the 10mm's I tried seem too big and 3/8" is too small. It's like its 9.75mm I'm sure he didn't want a gorilla on the line stripping the AL bracket, but he didn't figure the alternator would last 20 years or the Steel bolt and AL bracket would fuse together. A 30 minute job just turned into a 3 hour job that could turn into a 3 day job.

I'm soaking it in in penetrating oil for a few day, then will try so heat to see if the bolt will break loose. Alternator is original Jaguar.

Hope the junkyard cars come apart easier.

 

Had the same problem with mine a few years ago, the alternator had failed. Barely got the car home under its own power that day. The alternator is easy enough to remove despite needing to go at it from the top and the bottom of the engine bay.

I replaced mine with a generic recon unit from an Ebay vendor for about £170 (compared to £450 from Jaguar) and it has been 100% fine for the couple of years and 20K odd miles.


Not sure these pics will help anyone at all, but I took them when going at my car. I took the alternator apart but couldn't figure out why it had failed, although it was full of oil from the leaky camcover gasket I had at the time.


http://s192.photobucket.com/user/fra...Jag/alternator

 

I just had an alternator change in my 1998, but for the opposite reason...it was putting out 17 Volts. Some fuseboxes must be configured differently, because the positive feed to the regulator was a 5 amp fuse in position 2 in the engine compartment fusebox, not position 5, which I had to remove to induce the BATTERY NOT CHARGING so as to avoid damaging the electronics while I transited to the garage. And 12.59 is a good voltage for a fully charged battery.

Andy

 

Hi Andy,
I remembered your post when I was looking at the 97 electrical guide for Ungn, so I double-checked.

On the 97, the reg. is fed by the same fuse #5 as the starter relay, etc. On the 98, that feed was moved to a separate fuse (#2 as you have). Good idea really as a shorted reg. in the 97 will kill the power to the injectors.

Jaguar may have considered it originally as the 97 diagram shows F2 dotted...

Mike

 

Well after trying multiple different easy outs on the frozen 10mm bolt with no luck, I have decided to dremel it off. Sucks.

Changing the alternator should only take about 1 hour. Everything else came apart in minutes. Even the plug came out on the first try with almost no effort... but I'm going to have 3 hours in this one bolt.

My new plan is just get the entire bracket with the alternator at the junkyard. The cars in the junkyard are '01-02 so a little newer than mine. Core charge for the alternator is $6, so if I had a sawsall, I probably would have used it already on the alternator.

 

Mike

That was a very fortuitous change for me as if the regulator had still been wired through the same fuse as on the 97 I would have been dead in the water. A very good observation on your part.


Andy

 

After spending $50 on a set of bolt extractors to try to remove the top 10mm bolt, I spent $12 on a set of 1.5" Dremel cut off wheels. Alternator was free, 15 minutes later.

Getting the alternator out of the hole is a pain, though. I had to remove the suppresor/Airfilter box bracket which was under AC lines and then the alternator came out with millimeters to spare.

I might try to drill out the broken bolt, but probably won't.

I'm ready for the junkyard Saturday morning.

 

Success! Great day at the Junkyard today. 2002 XJ8 alternator came out in 15 minutes. Also scored a set of four 18X8" five spoke silver Penta wheels for $150 and the guy threw in a '99 XJ8 armrest with a good cupholder hinge for free. For $20 I went back for a pair of 325mm front Caliper brackets off an '01 XJR.

Total out the door for the alternator, bracket and pulley was $44. I paid $6 more for the 2 year warranty.

Slapped it in and voltage went right to 13V. Reset the windows and My jag is back on the road. Thanks again for every one's help!

 

Wow - great result!

 

Just curious, does the armrest have the console lid that fits the xk8 or were you just getting it for the cupholder?

Andy

 

XK8 and XJ8 armrest/console lids are mechanically the same, only the leather pattern/padding (and tire pressure sticker) are different.

The lid I snagged has perfect leather for being 18 years old and from Texas. It would look good in an XK8 and is slightly more padded, but I got it for the excellent leather on the cupholder door. The hinge on my door had broken years ago and the Previous owner closed the cupholder by pushing the leather lid under the striker bolt, tearing it.

 

Very late reply here but your comment was a lifesaver. I have a 97 XK8 that had a wiring harness damaged by rodents and as a 97 harness like an AN ECM is unobtainium I had to convert a 98 harness to a 97 by comparing the two. I got almost everything right such as depinning the EGR wires from the old harness and installing them into the 98. Also some pigtails changed/spliced in, a real frankenstein but connections were soldered and sealed.

Anyway the point is I missed one thing, the dedicated line for the alternator whereas in 97 it was bundled into the White/Pink wires on fuse #5 feeding the starter relay, FI relay /and ECM as well. I had cut and capped the White/Purple wire the alternator ran on so it wasn't energizing and not charging. I went back in to the brake booster area in the LF, cut the Pink/White wire and spliced it into the previously capped White/Purple wire and viola! problem solved. Thank GOD I didn't have to remove the entire harness again, 20+ hours of work.

BTW if anyone needs to replace a 97 harness with a more available 98, ask me how. 99+ does not have the two ignition module connectors so don't bother with those. A ton of sellers on EBAY say their harness are for 97-00 which is wildly inaccurate. The 97, 98 and 99+ are distinctly different just like the ECMs. If you have a 97 you will have the two large ignition module connectors in the middle and two black connectors on the brake booster side. The 98 will have the two ignition module plugs and a black and white connector on the brake booster side. 99+ does not have the two large ignition module plugs coming from the middle of the plastic U shape.

There are other wiring differences but this is a good way to see exactly what you are looking at in pictures that say "fits 97-00", LIES!

 

After 30 years as an auto electrician I can tell you that all alternator diode faults show as abnormality in the warning light ..even if the ignition is off the light can be on.
Check at night for a small glow in the WL which will indicate faulty diodes. Brushes can fail as can the regulator and bearings...best get a new one. Easy to fit ..take out the air box all from above