About a month ago I made a post here asking about starting issues on an 89 XJS V12 coupe. Everything pointed to an issue with the starter itself.

Fast forward a few days later, and I stopped in to see a friend for a couple of hours and when I got back to the car, it wouldn't start at all. The battery was clearly dead. His wife jumped me off and I got back home.

This past week, it happened again.

I have to mention at this point that the entire reason for asking a question about the starter is that my battery was scarcely 2 years old and it tested out as good down at the local auto parts house. I thought I had eliminated the battery from consideration.

Oops.

I had to have the car driveable immediately, so I purchased a brand new battery. You know where this story is going by now, I presume: Seven consecutive days of strong starts, no starter issues. On top of that, my interior lights are brighter, I don't get as many phantom seat belt light faults and my in-dash computer actually retains information from day to day. But the starts by themselves are so much better that the tale is really told right there.

What just flabbergasts me is how this is endemic to the Jaguar experience -- no matter the decade. There is nothing common about a Series II XJ12 (I used to own one of those) and a 1998 Ford-backed XK8, but have a battery problem and they suddenly act exactly alike. Both my XK8 and my wife's former 1999 XJ8 were infamous for weird stuff happening when the battery started going south: Batteries would hold a charge a couple of days, they'd test out as fine at the parts house, but all sorts of gremlins would be happening (the XK8's favorite: The little feature that drops the side windows a half-inch when you shut the door would stop working) and there was no fix for any of them.

Until you changed out the battery, that is.

So my advice to any of you who have an electrical problem you can't solve is this: Swap the battery out for a brand-new one, just to see what happens. My starter is fine; my battery was not.

Jess

 

Good on ya.

Batteries are the achiles heel of any car with electronics. So, maybe from 1987ish onwards, regardless of badge applied.

Down here we have a huge rise in battery sales with weather snap changes, but more so when there is a cold snap.

Batteries in cars are getter bigger, and have higher CCA, and RCA than ever before.

Then add to that, they are usually in the boot, so looooong cables to do what they must.

Daily driver batteries last longer than part time drivers, and that has been the case as long as long as I can remember.

 

I have had batteries tested under load at the battery shop and they test out fine. Twice they have been junk. I have a short commute to work and don't drive much around town so I have strapped a trickle chargers to my batteries, open the trunk/hatch when I get home, plop out the plug for the tender. I have had no issue's since and most my cars get under 30 miles per year. With my daily driver XKR I can get away without plugging in my tender for about 4 days of normal driving (new battery) and then the back up sensor freaks out reminding me it's time to plug in the tender.

 

Reminds me of what is still the funniest mod I've ever seen on a car: Lotus Esprit owners using the dummy gas filler door (apparently there's one on each side of the car depending on the year, but one is non-functional) to put in a snap-fit charging receptacle. Think electric golf cart. They pull the car in the garage at night, open the dummy fuel door, and hook a charger straight to the receptacle they've hard-wired to the battery. It's a plug-in hybrid Esprit!

Jess

 

I waste a lot of money working on cars because I hate to troubleshoot and prefer to just fix what I *think* is the problem. But I never consider replacing a battery to be money wasted because batteries are mysterious things and should never be trusted-even when new.

 

I do own an XJS, but my battery problem, which I actually have with all of my three cars, is worse with my XJR. The XJR suffers from this tedious and never-ending problem with the car going into this "limited performance" and "limp-home" mode when you least expect it. The most frustrating part is that what causes this can actually be one of several conditions and of which one is, yes, battery not fully charged. It is very frustrating not to know what's causing the problem the particular time, but little by little it is the battery that's the repeating culprit more and more, to the point that I can almost predict now when the limp-home mode will strike again. It appears that the condition will present itself every time that the car is not driven a good distance, and daily, even when this battery is only 8 months old.

We don't drive much any more, so with three cars, battery charge status becomes a problem. I have digital voltmeters in the cigar lighter receptacle of my XJS and my wife's Z3, but I need to modify the XJR's to "always hot" so I can monitor voltage with the ignition OFF. I even keep a chart on my fridge to indicate when a car was driven, how much it was and/or when its battery was charged last, etc. It tells me who gets the charger/maintainer next...LOL

Cheers,