Two days ago I went to garage to drive my Jag and when I turned the key no crank . I said it was from battery even though ampermeter showed just below 13 with the key II

Yesterday , I hit the garage again .I turned the key and again no crank and car would not start . Then, I remembered what I did when my previous Jag refused to start . I cycled the key 0-II a few times and finally after 5th shots it started like a champ as usual . Engine was dead cold .
So, my question here after a few details , if it was a battery it would not start at all , right
Next question is I think it may be from fuel pump but it was first ever time I had such problem on my current Jag and fuel pump related starting issues only occurs when engine is hot , is that right or it doesn't matter if your fuel pump is bad it won't start easily

I am perplexed if my fuel pump is starting to go bad or going off symptoms

 

Regent, to me it is sounding like a key programming issue, not a fuel issue. A simple check is to keep the driver's door open as you attempt to start the car. Watch the dome light as you attempt to crank the car. Does the light dim, go out completely, or remain really bright. If it dims, the starter is getting power, but then you should also hear a click from the starter engaging. If the light goes out completely, then a dead battery, if the light remains brightly lit, the starter is not getting the signal to start the engine.

By rotating the key a few times, most ignition switches are referred to as "self cleaning". So, by simply rotating the key back and forth, the internals of the switch were wiping away some of the oxidation that builds up naturally over time and managed to make an electrical connection again for you.

If it was a fuel pump failing on you, the motor would still rotate on you. When I see you say that the motor has a "no crank" condition, to me that means the motor never rotated. The motor rotating and the fuel pump running are completely different aspects of the car and you can have one without the other (fuel pump will run when the motor isn't rolling over, the motor will roll over even though the fuel pump isn't energized).

 

Thanks Thermo, I didn't know these tricks , much appreciated as always

 

I found that issue the other day. I thought I had a dead battery and for some weird reason I picked up my spare key and tried that one... surprise it started first pop.
Thinking it is a flat battery in my immobiliser key ring thingy.

Very technical terms hey. :P