My Jaguar failed me today. I drove into work like normal, but when I went to leave at the end of the day it would not start. The interior lights came on normally, the door locks worked normally, when I turned the key to the accessory position the radio came on normally. At this point I went to start it and everything stopped, like the battery had been disconnected, no power to anything. After disconnecting the battery waiting a moment, and reconnecting it, I got accessory power back, but if I tried anything that draws a lot of current, like the starter or the headlights, it would cut right back out.

My guess is that I have a short in my starter circuit, maybe the solenoid or the starter itself. But what I don't understand is why it cuts all the power for a period. It acts like a thermal shutoff but I can't really find reference to one in the manual. Does anybody know what kind of protection device is cutting power and where I can find it?

It's going to be a cold and raining while I potentially try to replace a starter in the parking lot at work. Can anybody who has replaced a starter motor in an '81 XJ6 tell me if this is even achievable in a parking lot without being able to easily lift the car?

 

Remove the underdash trim panel and jiggle the wires at the back of the ignition switch...any change? Ignition switch failures are fairly common and the jiggle test sometimes proves the point.

Also check the two "+" voltage distribution posts on the firewall. Connections clean and tight?

Indeed it might be that the starter has failed and is drawing SO much amperage that the other circuits are starved.

This checklist will take you thru some easy checks:

Engine Will Not Crank Checklist

Cheers
DD

 

In addition to what Doug has said.....

I'd look at the ground connection on the battery closely and make sure that is good, tight and clean... You may also want to have the battery itself tested...

As far as changing the starter in the parking lot.. I sent one to a guy at his hotel one time. He pushed it on a curb and changed it right there. Having done that job a few times, I admire him for that...
The last starter that I changed I did everything from the top side. It was challenging, but doable... The area the bolts are in is extremely tight.. But it really doesn't sound like a starter issue...

Try turning the ignition to the start position and taking the red/white wire from the starter relay on the firewall, and touching it to the battery positive.. The starter should engage, and the car may even start....

Cheers
David
shop.EverydayXJ.com

 

I have done the starter in my S1 on the side of the road from the top. As David has said it is doable . I can see yours would be more challenging being fuel injected and LHD with the battery on the right side of the car.
At least with mine I could see the back of the starter motor.

Didn't have to battle cold and rain, I had a 40+c day working in full sun. Not sure which would be worse.

 

yes to:

1) check the cables connected to the battery,

2) could be the ignition switch worn out. You can open it and fix it.

 

All of the above are certainly good and valid points.


I would add a personal tale that just might get you home or to a shop!! My Jeep is powered by an OHV straight six. The starter is on the low right side of the engine.
Similar architecture, but the starter is much smaller and lighter.


A couple of years ago, my daughter and I went to lunch. Ina nearby shopping center park lot, I twisted the ignition key to fire up the beast and start for home. All went dark and no crank!!! New situation to me. Odd, I've had a lot of critters, but none ever did this!! Although, I thought the battery terminals were clean, I started there. cleaned and reattached. Same result.


I recalled reading of an old technique. Percussion!!! I got out my shileaghleah (sp),
and gave the thing a couple. Daughter turned the key. Yahoo, it cranked. As the Jeep engine, although very experienced, fires easily, it started. Away we went, dropped daughter and on my way home. Parked in the driveway in a "convenient" place to work and not block the Jaguar in the garage. Shut it down. As expected, no crank.


My diagnosis: Starter plumb wore out. A bit fiddly to replace, but not all that bad. Rebuilt unit from local CARQUEST. Cranked right up.


In older times, I'd try fixing the old one. Bearing, bush, bushes, commutator clean and scrape fixed many of my old ones.


In the case at hand, that is my diagnosis from afar.


Carl

 

Added to the above check the negative connections to the engine and body.

 

Ok, update. Sorry I didn't get back sooner. To those of your who suggested it was a ground issue, you were spot on, that's exactly what it was. Thanks for all the suggestions and reassurance, you all continue to be the best resource out there for these cars.
The ground from the battery to the car was apparently not so good. It looked good, felt tight, but some corrosion or something had caused it to be trouble. It only seemed to let go when I tried to push a lot of current through it, and then by the time I got around the car to check it everything would be fine. Lesson is, just because it seems to be making good contact when sitting around powering the interior lights, doesn't mean it will work when you crank the engine. I won't be fooled again. After many confused attempts to start the car, having the power cut out, and then going to probe around with my multimeter and finding nothing the matter, it finally stayed out for long enough for me to find no continuity from the battery to the frame and zero in on the right connection.
I cleaned it up with a wire brush and got it tightened down good, now it starts faster than it ever has so I suspect it has been a lot of my trouble for awhile now.
Since then I have developed a fairly profuse coolant leak, never a dull moment, but not being electrical related I'll post another thread for that.