My car sat for a few months and came back to this...if anyone has any recommendations let me know! here is a link to the vid of the problem ---> https://drive.google.com/file/d/1nJI...ew?usp=sharing

 

Watching the voltmeter that is very accurate you have a expected voltage sag to X , hard to see so let me expand the video size to see it better

9 ? which is too low , 9 would not be bad starter solenoid relay power contacts related but good relay power contacts

You also have a good solenoid itself as the extension ( somewhat ) and the battery cable power contacts inside the solenoid to account for the voltage sag

the large clunking is the starter solenoid expanding the starter motor gear into the starter ring

This means you have all the agreements for starter engagement, so you are past that point

Some things you can try is to swap the starter solenoid relay as it may have burnt power contacts , agian 9 volt meter reading says it's OK

This relay is the same for the headlights , fog , A/ C clutch

Battery good ?

Never install battery in backwards and never over tighten the battery positive post bolt

So you have a battery cable current / power " supply " issue

Take a look down through the intake pipes for the starter solenoid top terminal post nut for being loose heavy battery cable , 13 mm socket , 3 inch extension from under the car but maybe from top ? Check the large starter ground strap from the starter mound bolt to the chassis ground , 10 mm while there , this definitely from under car , the large starter voltage sag says the large ground strap is good

B1mcp ( Brendan McPhillips ) had a good pic of this

There is a large battery cable ( starter cable ) terminal post on the right wheel well sheet metal inside the engine bay about 4 inches from the rear engine firewall that can give problems , remove battery cable and wiggle post , this is point ST3 on the top red line in the diagram pic

This starter cable goes both ways as the starter umf from the battery and in reverse to go between the alternator and the rest of the car ( battery charging and fuse boxes to power systems )

You have 2 more terminal post to the battery as the umf goes fwd , one easy and one hard before starter removal

Right at the battery positive post as it turns down ( point ST8 )




And under the rear seat pan as you remove whole seat pan under a black triangle cover ( point ST6 )





Battery positive post shims ? clamp stretches over time , put some battery terminal red oil under cap to a clean terminal post

 

Thanks for all that info. When I took the video the car was being jumped by another car (had to do the old engine jump truck to open trunk routine) so it wasn't under its own power. I've had the battery on a tender all day since and still have no power. So could it be as simple as the battery is bad so it won't start?

 

First thing is take to a common auto parts store to load test , but is a Sunday afternoon , this test takes a hour at the / on their store equipment time

A tender will take forever to recharge , the 13 volts on the gauge was the jumper cart

But keep it charging overnight to be best before auto parts store test time , but it may just start

MAY HAVE A PARISITIC BATTERY DRAIN TO LOOK AT AS A 2nd SUBJECT and new thread

Jumper cables positive cable car fwd post ?

 

Sounds good, thanks again! I've been trying to decipher what battery the car should take as well. The big box auto stores are recommending group 45 battery's but to my knowledge I thought the Vanden plas was suppose to have group 49? Any insights on this in case I need a replacement?

 

The VDP has rear seat heaters and sometimes in the glass gold film in the front windshield heaters

So in the car starting on a cold day sequence.............................

From my understanding the same 120 amp as other versions of X300 alternators for a starter duty cycle recharge time

can you skimp on the BIG X300 battery.? - Jaguar Forums - Jaguar Enthusiasts Forum

AND

Best car battery for 95 XJ6? - Jaguar Forums - Jaguar Enthusiasts Forum

 

As well as all the good info from Parker another battery lead connection to check is where the cable passes through the firewall. It will be in the RHS front footwell close to the transmission tunnel. It is a brass stud, threaded on both ends and it passes through a plastic insulator and because of where it is it is impossible tighten without the help of an assistant.

All the battery lead connectors, from the battery to the alternator, in my car were loose when I bought it and cleaning and tightening them all solved a battery charging problem I had.

Cheers,
Jeff.

 

Because of all the issues I had with my XK8 and the codes that came in when the battery went totally dead, I keep the batteries on my XK8 and X300 on a battery tender all the time. On the XK8, if it goes too low, you will start seeing some really crazy codes in reference to all kinds of communication bus issues. Until you clear them out, charge the battery you will think that all hell broke loose.

 

Jeff ,

" On " lower right firewall plain area terminal post / through as it continues inside right fender quarter panel up to the inside engine compartment right wheel well sheet metal terminal post ( 4 inches fwd of rear firewall plain ) . Thanks

That is one thing I was not aware of ( your detailed work ) in my long going and current starting issues and will look into at the through firewall terminal post and get pics of it

My car was wrecked on the right and replaced right front quarter panel by the previous owner

So it makes sense

The right lower footwell 48 wire RS3 engine regulation connector was damaged , and they did a half ars job of salvaging the original connector ( tie wraps together ) which led them to abandoning the car to me with 110 K miles , with I'm sure many reliability issues hence low miles for me to enjoy , one being the fuel pump relay command close wire that surprisingly goes through RS3

I did bring a long very heavy thicker than the original gauge # battery ( professionally made at a battery cable shop ) cable around the outside of the car from the rear seat terminal you made me aware of to the terminal post on the right engine bay wheel well terminal post ( ST3 ) but my work at that time may have been lacking

Car does run if starter rotation

 

Here is the first video I took, not showing any oil pressure.... https://drive.google.com/file/d/1pIj...ew?usp=sharing

Second Video only a couple minutes after first, now showing some oil pressure but still not turning over... maybe its not getting any spark? Should I check and replace spark plugs/ coils? https://drive.google.com/file/d/1onh...ew?usp=sharing

Thanks for any insight!

Also, just found an obd scanner and this is what it spit out, not too worried about the top one bc there is no cat on the car. https://drive.google.com/file/d/1pU7...ew?usp=sharing

 

To supply power for the engine there are 2 relays

# 9 small relay in the corner of the right engine bay fuse box ( this fuse box has fuse X ) that closes the starter solenoid relay and powers the ECU with fuse A

The starter solenoid relay control fuse is X , the muscle power through the starter solenoid relay is fuse Y ( hot at all times from the left engine bay fuse box )

# 5 large ECU controlled relay that brings power back into the ECU , half of your engine sensors , and powers the fuel injectors to open

Fuse B and C for the # 5 large ECU control relay

Place your finger in these 2 relays and feel for click with key in run position , you can do this yourself by removing the relay

To get the # 5 large relay to close the # 9 small must close first as the ECU low power section controls the # 5 large for ECU high power section

You have cheap relay swapping options , left engine bay fuse box as this relay only controls the car horn , and headlights , fog , A/C clutch for the large

There is a fuse that controls the fuel pump relay as fuse Z and that fuse requires the right heelboard fuse box relay in the corner to close

same click test as before

The common denominator is the ignition switch and it's ground path through pin 5 ( no need for a new ignition switch just yet ) you can change this switch if needed and no new key or key barrel

I'll get you X , Y , and Z later but the emphasis here is on a intermittent or hard fail relay closing