I can't get it started , this is really puzzling considering my jump starter help even far more dead batteries bring back to life but in my Jag it doesn't . I ascribe this starting problem to my battery , it's around 2.5 yrs old . I will have to try car to car battery jump but there is a catch . Our late models battery are located into the trunk and where is the best place to attach negative battery cable for the cars with battery in the back I don't know exactly . I thought about trunk lifters but don't know for sure

So, my question where is the best place aside from engine block to plug the negative cable


One of the images I am uploading is showing the battery volt with the ignition key is in II . I suppose this is a normal value

 

I don't know what model you have (XJ40?) but it might be that attaching the negative cable to the battery is the only plausible choice.

With the booster pack attached (and assuming it's fully charged) you should show about 12.0-12.5 volts on your volt guage. Yours looks a bit low...although the gauges are not always accurate.

Maybe you have some weak/dirty battery connections or grounds?

Do you have a battery charger? If so, while the battery is charging for a couple hours you can busy yourself by cleaning the cable ends, ground point, and "+" junction posts in the engine bay.

Cheers
DD

 

+1 ^

Caddie if that gauge is only showing that with the booster pack added, then I would think that your battery is flat.

My XJ40 pretty much won't start at that level.

Why not 'borrow' one of the batteries of another car, just to see?

 

I am subscribing to the thread.

 

Don't forget the warnings about getting a clean connection. In other words, no spark... spark ... spark ... connect. It causes multiple reboots in the various computers.

 

Is the starter engaging the flywheel and is the engine rotating? If that is taking place try starting in “N” and not “P”. Still no start check to see if you have fuel and spark. Fuel using a pressure gauge on the scherador valve XK8 & S-Type Fuel Pressure Test if that is ok then test for spark and you can do this with Sears: Online department store featuring appliances, tools, fitness equipment and more or Sears: Online department store featuring appliances, tools, fitness equipment and more

 

Someone else here had a simple way to test for spark.

Mount the coil on extra spark plug, jumper from extra sparkplug side electrode to engine sparkplug connector.

spark should be visible jumping gap on extra spark plug when firing.

 

Thanks everyone for your valiable inputs
The car is 1993 XJ40 .
I heard just a click not a cranking normally in other cars instrument clusters go crazy and hear a quirk sounds but that was not a case in my Jag yesterday . I will give it a try later today and will let you know how it goes , hopefully good news

What makes amazed me was that battery booster didn't work normally it worked as supposed . I have help other cars roar back to life thanks to this machine .
I can't point out + ground and I think it's a weak battery since you said it was a bit low to get it started . Honestly , it's been more than a week since I last started up the engine

 

Happy end lol

As you can see in the image, car to car jump cables worked marvellously .
Trunk / boot hinges are OK to simulate engine block for the negative ground , please do not clasp trunk lid locking for negative ground , it is not a proper choice .
Trunk hinges are ok as you will se ein the image . After this mod , I turned the key to II and voltmeter hit 13 mark and car roared back to life
Thank you for your helps

Final score is

BATTERY BOOSTER 0 - CAR TO CAR JUMP CABLE 1

 

Kudos to you!