Last year around this time I purchased my unicorn dream car. A 1996 XJ12 in British Racing Green with a cream interior. Here in the states the 1996's were only available in LWB which is why I wanted a 1996. I've wanted one of these since I bought my first Jag in 2003 which was a 1995 xj6. I had never seen one with this exact spec for sale until last year I saw an obscure post on facebook marketplace. I wonder how many 1996 BRG xj12 with cream interior were imported tot he states? This car was being sold by the daughter of a rather old lady. It had sat in a garage for 14 years. Non-running. Apparently they had a mechanic try to get it started but determined the fuel pumps, gas tank, and many of the fuel lines were rusted out and shot. The interior looks very good and the exterior isn't bad. There appears to be some (hopefully) surface rust underneath. We agreed on a price of $2500.

My intention is to eventually go through the entire car and try to bring it back as close to new as possible. However unlike some of my other projects I don't want to do it all at one time. I'd like to use it some during the process. Here is a photo of the car on the way home after purchasing it in NY.



Their mechanic managed to bugger up the stuffer pins trying to get the gas tank out. Which they never did. I've got the tank out and have removed the disgusting fuel pumps and done a first pass at cleaning the tank with muriatic acid. I can't find pics of the fuel pumps but will take some soon. I ordered new denso fuel pumps, seals, and stuffer pins. I don't have a lot of time to work on this car but I do want to try and do something once a month or so. Before it gets too cold (as the car is currently outside) I would like to do something fun and motivational by trying to get it started by using one of the new pumps and rig up a temporary fuel system with some long exterior runs of fuel hose to the engine. I had been thinking about this and then recently saw "To The Garage" on Youtube do the exact same thing trying to start a XK8. I also have a XK8 that's coming into my shop for some service and repairs. Hopefully this will be done in about a month or two. After that the XJ12 can take it's place. My plan would be to replace the fuel system from the tank up, get the engine running, get the brakes working, then take it for a drive! Assess what else it needs then tackle projects one at a time while driving it in between.

We all know how the plans go but at least this project has started and my XJR project is essentially finished as I drove it home today!

 

Hi, I’m not sure what stuffer pins are… but my car had the same bad fuel pumps. Bought it as a non runner with no brakes also. You’ve done half the work taking the tanks out, I’d throw the pumps back in , change the fuel filter, and try to start it. I wouldn’t trust a mechanic I never met with his “I don’t want to work on this” diagnosis. If the fuel lines don’t shoot gasoline, they’re good enough to start the car.

good Luck!

-John

 

I do not have the V - 12 but the chassis systems are almost the same

Something to keep in mind on initial engine start up is the # 1 fuel pump will only come on for 3 seconds only then off , will come back on for the duration of drive once the engine crankshaft speed sensor sees engine rotation

A good CKPS will read 1300 ohms resistance as a basic meter reading ( V - 12 has 2 CKPSs off the top of head ( one front , one rear )

This initial 3 second fuel line " charging " is different than cylinder " priming " , no pumping of the pedal in any case

There is a secret small fuse # 10 that is the control power to control the fuel pump relays ( both on 1 fuse ) , see below , this fuse must have the small relay in the corner of that fuse box close , swapping option is the left engine bay fuse box relay ( only runs car horns )

Your initial starting try may involve taking the key from the run position to the off position several times to fully charge the fuel lines ( 43 psi by the on car fuel pressure regulator )

You may have to easily recondition the cylinder walls of a " bore wash " condition as a stored car ( common from reading other stored X300s )

The stored car may have the security system fuse pulled for storage ( trunk fuse # 3 or # 4 ) , alive security system need as one of the starter enables

With the car out of service for that long of time may need a termed easy DIY " hard Reset " that resets the security and body prossesor unit ( starter enables summing unit ) to zero state , this does not effect engine ECU at all

Your fuel line map is at the beginning of the 801s doc and the fuel filter is flow arrow to car's outboard

Your # 2 fuel pump will not come on until 4000 RPM but can be tricked into using on first engine starts

Check the check valves on both fuel pumps before installing ( needed on engine start sequence ) , on lessor pumps these can be bad out of the box

Motorcarman ( Bob ) would know more on your import numbers / interior color status and of the LWB / SWB V - 12s versions as he comes across this most likely if you repost on the X300 inline 6 section / area


You do know about swapping the X300 headlights ( X300 silvering rubs off ) to the cleaner and better X308s ? tricks involved before disassembly or you can get lost

Oliver Marks ? fresh meat

 

Parker is the king of the electronics, I can't add much on that but I would suggest having a couple of fire extinguishers ready. 6.0 v12s have some fuel injection hose weakness areas. A close inspection of all the pressure hoses would be an excellent idea, particularly the easy to see fuel rail hoses across the top of the engine front and rear (under plastic engine cover). You don't want to get the car running and then have pressurized hoses squirting gas on a hot engine.
I know winter is closing in but you are far more likely to find parts cars in wrecking yards in the NY metropolitan area than most other parts of the country. Seattle seemed to have a lot of xj12s as well. Presumably mid 90's wall street and microsoft I'd definitely keep an eye out for unobtanium parts like the radiator, water pump etc.

Regarding how many are left, very few I suspect. Only 196 were built in 1996, thank goodness for all the x300 parts cars!

 

On a sitting car fuel pump frozen , use a battery charger that has a higher voltage ( force ) value than a fuly charged battery of 12.75 to free up stuck pump , battery charger values can be 13.5 and up depending on Amp setting

Quick and dirty direct powering the fuel pumps ( minus the car designed to operate )

Jumper the fuel pump relay's between socket 3 ( hot at all times battery / fuse direct power ) to socket 5 ( pump )

Use blade type jumper ends on medium gauge wire for best performing connection

on fuel pump replacements the relays should be replaced with new as the power contacts inside the relay pit and arc when the pump motor is giving up , as well as inspect the on the pump motor connector for pitting sockets ( the pump motor connectors are commonly available )

On some aircraft electrical motor replacements , it is required to replace the associated relays per instructions which must be followed

There are some pointers on things to look for inside the tank as these have tripped up a few in the X300 section if you open up a new asking thread

Joseph Barry
Flight Line Avionics / Electronics
American Airlines ( retired )

 

Relays from x300s are a regular haul at junkyards for me, can't have enough of them. Never occurred to me they might be arced out, thx for this

 

G'dat Oliver,

The blue relays, or the equivalent, can have the cover removed and the contacts cleaned up with some emery paper. You can slide a thin blade down where the catch is, there are two, one on each side, to release the cover.

The black relays are a bit more problematic as there are catches on all four sides but it can be done.

As an aside I have a blue relay with the cover removed for testing relay circuits without trying to hotwire the right pins, I just plug it in and squeeze the contacts together.

Cheers,
Jeff.

 

A jumper wire in a trunk tool box may save a towing on fuel pump failure

Oliver , the small peanut relays in the heelboard area would be good , security and such as they are not all the same part #s

American Airlines instituted a TSB ( Airworthiness Directive in the big jets in sky ) to bring up hydraulic pumps ( 3000 psi ) connectors to new

In the end as the FAA level of confidence and getting caught on a Southwest fleet wide pencil whip ( cheat ) ;, AA took 3,800 ( three thousand eight hundred ) flight full cancelations on a non - safety issue to make the FAA like the hero's

 

As it was a gorgeous day today in Maryland, and I had a spare 30 minutes, I managed a small task on the XJ12. I managed to vacuum and blow off the top of the engine and the rest of the engine bay. I found a dead mouse, a mouse condo, lots of nut shells, and misc crap and dirt. I managed to use my spark plug wire puller for the first time. One at a time I pulled the boots, blew out around the plug, and drench in penetrating oil, then put the boot back. Of course this is leading up to trying to start the engine. It was a small task but it made me happy. Next will be to remove the plugs, lube the cylinders with some fogging oil and some marvel mystery oil. Looks like we will have good weather for a few days so I might get a chance to work on this again as it's stranded outside for now.

Thank you everyone for the notes above. I've been collecting parts for this task and today made a stubby fuel line adapter to go into the fuel rail. I'll take a photo or two of the setup when I actually do it.

 

Keep in mind of the check valves in the existing fuel pumps , if either pump check valves bad will not hold the 43 PSI at the fuel rail / injectors to start

If you get a buzzing , noise , and becomes warm the XJ12 fuel pressure regulator , a good sign the pre fuel lines holding pressure ( good check valves )

 

I was able to put a few hours in today. I changed 11 spark plugs and lubed the cylinders. I had to sneak up on about half of them with one not playing nice. That one will have to wait until the engine heats up.

I bought a set of generic check valves along with two new denso fuel pumps. I just might get to try this out tomorrow.

 

There was traffic in the X300 area of adding external to the tank , check valves of a certain # that others including moderator Don would know about

Old fuel replaced as this is critical on the inline 6

A 1 / 4 inch X 6 foot siphon hose will fit past the unleaded fuel only nozzle gate , on some X300s from reading some have a dedicated siphon trap further below

 

Update guys. Saturday evening I was able to finish the temporary fuel supply setup and try to start the engine. I hooked up the fuel pump using the cars wiring in a small plastic jug in the trunk. I used a section of rubber hose over the roof and directly to the intake side of the fuel rail. On the return side of the fuel rail I ran a rubber hose to a check valve and then over the side and into another small plastic jug. I used fresh 93 Oct gas with some fuel system cleaner and flushed out the fuel rail until it was clear. I put a shot of starting fluid up each intake tube and turned the key. It started instantly!! I could tell when the starting fluid burned up in a few seconds and then it ran rough and stalled. It started right up again and started to run better. I only let it run for about 30 seconds as it was squealing with a burnt rubber smell. I suppose one of the things belts are supposed to turn isn't turning. Overall this was a good day and provides some motivation to carry on. I'll probably remove the belts and hear it run for another 30 seconds or so before putting a pause on the project until I get it inside.

 

There are 2 ignition control modules for the 12 cylinders 12 coils , how you would trouble shoot from there......... , there is a splice that can be bad as the power is shared between the 2

 

Suggest starting it and looking at the various accessories to see what is not rotating before removing the belts. Water pump is obviously critical.

 

Which engine ECU do you have as this determines the engine regulation as either Nippon Denso ( Japan ) including the injectors ) or Lucas - M something as the earlier version

Your 801s doc covers mostly ND but have them mixed together as they put the Doc out

 

Turns out it was the idler pulley on the ac belt that was locked up. I didn't have time to mess around so I just cut the belt off as I'm planning on replacing them all anyway. I'm not sure what's next. It might be several weeks until I move it inside to start work. Perhaps I'll start ordering parts!

 

If the idler pully is the same as on the inline 6 it is a common generic part

The long belt adjustment bolt can be frozen if the same as inline 6 and there are some tricks

 

The pulley appears to be unique to the 6L XJ. While still available, it's probably possible (and cheaper/faster) to press out the bearings, measure them, and replace with off-the-shelf parts.

 

I had a dodgy idler pulley bearing in my car when I bought it. The original pulley was plastic and the OEM replacement was a metal pulley which is still on the car nearly 20 years later. I have replaced the bearing in it at least once and it is a common size and readily available and easily R&Rd.

Cheers,
Jeff.