The heading says it all. I turn the key to start the engine, the engine cranks but the fuel pump doesn’t operate. When I remove the key it is still buzzing and I need to disconnect the battery to stop it. I reconnect the battery and no buzzer until I turn the key on again.
The fuel pump does operate when I hot wire it and pump to about 20 lbs.
First, you are clearly having troubles with your ignition switch-possibly caused by a messed up lock cylinder. Check switch wires/ local fuse box to see what is hot/ cold at each position. The car is a bit fancy-with more than its share of miles of wires, but the ignition switch is not overly complicated. Biggest bug a boo on my car is the Jag. special mechanical steering wheel lock.
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You could try lubing the ignition switch and see if it helps. Sometimes things get sticky in there. Not sure if it’ll help with everything though
Rodney,
Well the heading doesn’t say it all. 
What is the year and model Jaguar are you asking about and what engine does it have in it?
Did you own and drive this car for a while without issues and this just started to happen. Or did you acquire a non running car that others have worked on before you and you are trying to get it running?
Paul
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The buzzer switch is inside the ignition switch, so start with that, if some WD-40 doesn’t do the trick, at least temporarily, you will maybe have to start disassembling.
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Paul, you’re absolutely right. I neglected the pertinent information because I forgot that I am not posting in my usual topic which is the “86 Jaguar V-12 convertible project”. A car I bought not running and after much hair pulling, broken and mouse chewed wire repairing, fuel injector replacing and rewiring ,got it running and starting well then parking for winter and then bringing back to the shop for oil leak repair at valve cover, then not running as it should. During the tedious trouble shooting of this condition I developed this problem along with a fuel pump not activating when key was turned (operating with hot wire though) and the switch buzzing. Thanks for pointing out my lack of info. Thanks
I will do what I should have done first, lube. This car has me going in so many directions. Thanks for giving me that starting point, again.
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When I swapped out my ignition switch I found an extra pog tail that was not connected. it lead to a flat cylinder. much like n old tech snuff can. I connected it to my NOs switch. lottsa of odd tigns got fixed.And, a buzzer! Clearly, a PO had disconnected it.
My source for the Ns sitch was David Boger at everydayxj. God guy and great prices and service.
So, in the case before us, is it the buzze or is it the fuel pump nise?
Way back when I was hooking up wires to the LT1 swap, i heard what I thought was the fuel pum. Naah, merely the radio antenae going u and won as I messed wit wire splces and my VOM to idtehm.
CHJ
I’ve had my doubts about this switch since I’ve owned this car but I had put them on the back burner because I had gotten it running. I am back to my doubts again. The key seems sloppy to me when inserted, not what I’m used to when inserting a key into any lock or ignition switch. I will give it a squirt of WD40 as suggested by previous responders. I will keep David Boger in mind . Thanks for the info.
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No dobts!
My old switch was quite sloppy. My new one is taut.
A better switch is in your future.
CHJ
Be sure though to use that dry graphite powder spray to do so, as liquid lubes can lead to further issues with the lock down the road (i.e. attract dirt and dust). I find that spraying some in there and on the key as well usually gets the “interlock” thing to working smoothly again. When you remove the key from the ignition slot, you should clearly hear a “click” as the interlock engages. If you don’t hear it (i.e. it is sticking and therefore causing the “key left in the ignition w. door open” warming chime to ding), sometimes sticking the key in and removing it several times will trip it. Also, a firm hammer with the fist to the steering wheel rim on that side can sometimes work. 
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I wonder if modern spray silicone lubricant would be just as good/better as it helps clean, and then completely dries, leaving a film
When, i replaced the igntion switch in my XJwuzza six, I only got one key. Soas to get a spare and insure that it would work, i took the seitch to the local locksmith. it ook some doing, but, he foud a blank to cut.
and for the fun of it clened/lubed the lock wit a blst of a liquid.
the spare fit and worked perfectly. I use it as it is different than the key to my Jeep.
I do reall the little graphit squit tubes. log ago, i may have had oe?
CHJ
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What would be some common names for these products, Timer? 
I was thinking just a generic silicone spray lubricant made by several manufacturers. I get the stuff at Rural King usually. I also have a graphite spray lube that would probably “get further in” and possibly leave a better layer on everything.
The dry graphite spray lube seems to be what members here advise on using for the job, or, for that matter, anything involving electrical locks. That’s what I use, spraying some both into the lock and onto the key itself. 
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Thanks I’ll give it a thump or two next time.
I have run into issues where the seat belt buzzer stays on, and comes on at weird times, like others have reported.
Recently, I have developed an infrequent but really annoying problem where the car won’t respond to the start roll (rolling the key all the way forward to engage the starter). I usually have to roll the key back and forth a few times to get it to go. Sometimes, a great many times.
Reading this thread and a couple of others similar to it, I determined that the contacts in the key cylinder were probably oxidized and the springs (if they use springs, that is…) gummed up.
I did not want to put graphite in the cylinder because its conductive. And, I saw the post by one lister on not using WD-40 or silicone lube.
What I ended up using is De-Ox-It, a spray that I use on pots and switches of old tube radios to clean and lubricate the inner workings of potentiometers and switch and relay contacts. Thing is, I stuck the thin tube into the key cylinder, and the cylinder acted like a ‘chinese finger lock’- I could not extract the tube! I found a nail set and used its narrow nose to depress part of the entry to the lock, and this was enough to release the tube!
A few rolls back and forth, and now the seat alarm works as it’s supposed to, and, I have not (yet) had a repeat performance of the no-crank problem.
Fixed? Maybe. Improved? Sure.
-M
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The graphite powder is conductive ? I guess that makes sense, since it comes from lead (?) All I know is it is the recommended “lube” for such locks and switches vs. silicone, white lithium grease, WD-40, etc… I would think if it is conductive and that causes “issues” it wouldn’t be …
Paul:
Graphite, even in powdered form, is electrically conductive. Graphite electrodes are used in arc furnaces in steel production, for example.
Perhaps what makes it work for key tumblers, or in some cases, where folks are using it on ignition switches, is that the powder particle size may be much smaller than the gaps between contacts, and small enough that it never seems to accumulate into clumps that could gather between contacts, possibly promoting a short if it found the right pair of contacts. I dunno.
I was simply giving my own reasoning behind giving de-ox-it a try.
My own de-ox-it experience: so far, so good. 100% starts/cranking and no aberrant seat belt alarms. Again, so far.
-M
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