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garethashenden New Reader
4/6/20 1:06 p.m.

About time I contributed something to this great forum...
I've always wanted an XJ-S and when offered a 1987 British Racing Green V12 coupe for free it's hard to say no. It should have been $2000, but the economy kinda fell apart and that didn't seem like a good idea anymore. Luckily for me the seller was moving and needed it gone, so now it's mine. I ended up paying $100. Its been parked in a garage for 5 years mostly untouched. Originally form California, it's been in Massachusetts since 2000 and amazingly remains rust free! It's not currently running, but was running when parked. Unfortunately it wasn't running great, which is why it was parked. 
So far I've changed the oil, drained the old gas, and pulled the fuel injectors. I've sent them off it be serviced and tested. Next up is to change the fuel filter and the spark plugs. The filter is easy, the spark plugs not so much, but that seems to be the XJ-S new owner initiation ritual, so there we are. I'll also do the distributor advance cleaning thingy while I have access to it. Once the injectors come back I'll put new gas in and see if it goes. Then cooling and brakes. Should be fun!

mr2s2000elise Dork
4/6/20 1:09 p.m.


Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
4/6/20 1:23 p.m.


Gunchsta HalfDork
4/6/20 1:32 p.m.

You are brave. These cars look super cool but are intimidating as hell. 

garethashenden New Reader
4/6/20 1:40 p.m.

In reply to Gunchsta :

In a way, yes. There is a lot of stuff under the hood. But it's all 33 years old at least. The engine was designed in the '60s, as was the suspension, and the body was designed in the '70s. So there's very little in the way of complicated computers. Even if they wanted them, Jaguar couldn't have afforded them. So once you get past the mess of hoses it gets better. After only a few hours under the hood I'm much less nervous about getting stuck in. 
Before I started:

AngryCorvair (Baller)
AngryCorvair (Baller) GRM+ Memberand MegaDork
4/6/20 3:16 p.m.

i opened this thread thinking it was "For Sale" but my wallet and i are glad to see it in "Builds and Project Cars" 

TurnerX19 Dork
4/6/20 5:59 p.m.

The first time it gets a coolant leak replace every single hose. there are at least 17 of them. Chances are they are all ancient. Beyond that they are really far better than their reputation. I'm glad to see this one saved, too many are being parted out.

jr02518 HalfDork
4/6/20 6:10 p.m.

Keep an eye on the water pump.  For some reason they wear out and do not give you the normal tell's that they are going bad.  I had a '73 xj 12 and it was a fluke that I found mine was an issue.  I had a bad belt, removed it and on a wim I spun the pump.  It was a sound I would have never picket up with the motor running.

I was able to RnR the pump without removing the radiator.  Loosen it, but not take it out of the car.  Many four letter words, but the A/C stayed in tact.

FYI, the A/C compressor is located between the "V" on top of the motor.  Right above the the water pump.

TED_fiestaHP Reader
4/6/20 7:31 p.m.

  I always liked these, somehow I haven't bought one.  I will follow along, should be a interesting build.

     I have heard it is set up as 2 six cylinder engines, 2 separate fuel injection systems.  But I have never worked on one.

        I does look rather complex.

           I did hear the air filers limit air flow, might be some untapped potential available.



garethashenden New Reader
4/6/20 7:47 p.m.

In reply to TurnerX19 :

I've already ordered a full set of hoses. I'm not going to mess around with the cooling on this car, it's all getting replaced/serviced before I put the car on the road. I'll get the radiator cored and cleaned. Not sure about the water pump yet, haven't looked into the possibilities, but it will get a new gasket at a bare minimum. I'm also planning on fitting electric fans in place of the mechanical one. Apparently there is a ford fan set that is essentially bolt in. 

garethashenden New Reader
4/6/20 7:51 p.m.

In reply to TED_fiestaHP :

The fuel injection is just one system on all the cars, as far as I'm aware. The distributor on the later cars ('89-'96) is two six cylinder distributors on top of each other. 

They're very well documented cars. There's a 700+ page pdf of accumulated XJS knowledge. All the original issues are now known and documented. 

Datsun310Guy UltimaDork
4/6/20 8:18 p.m.
TurnerX19 said:

The first time it gets a coolant leak replace every single hose. there are at least 17 of them.

Ha ha. 

garethashenden New Reader
4/11/20 3:55 p.m.

Got the spark plugs changed. Since I'd already removed the fuel rail and injectors it was pretty straight forward. The old ones look like they've been running rich, quite black but not oily. I've also got leaky seal somewhere, probably the windshield. The carpet is wet. Damp on the passenger side, dripping on the driver's. I've pulled the carpets out of the car and I'm letting everything dry out in the sun. It looks as if a previous owner tried to reseal the windshield as there is sealant all around the gasket where there shouldn't be any. It could also be one of the door gaskets, but since both sides are wet I think it's probably the windshield. 

Here are the spark plugs, 1A top left, 6A top right, 1B bottom left, 6B bottom right

NOT A TA SuperDork
4/11/20 7:37 p.m.

Leaky heater core perhaps?

TurnerX19 Dork
4/11/20 8:23 p.m.

Plugged up plenum drain will wet the floor too. there are 1 or 2 thin rubber spherical/slit one way valves along side of the transmission that plug up with tree crap. Go under and squeeze them. Listen for crunchy sounds, and be prepared for a streamsurprise 

alfadriver (Forum Supporter)
alfadriver (Forum Supporter) GRM+ Memberand MegaDork
4/11/20 8:34 p.m.
TED_fiestaHP said:

  I always liked these, somehow I haven't bought one.  I will follow along, should be a interesting build.

     I have heard it is set up as 2 six cylinder engines, 2 separate fuel injection systems.  But I have never worked on one.

        I does look rather complex.

           I did hear the air filers limit air flow, might be some untapped potential available.



If you were going to update the controller, IIRC, the MS3 will run a V12 by itself.  Which would be massively simpler than the original Jag system.  Although, if the two manifolds are not connected at all, it may be a little easier to tune as two I6s.  Updating that computer would be pretty high on my list.

garethashenden New Reader
4/16/20 12:40 p.m.

Just got the injectors back. Eight were working well, two were working but not well, two were not working. That's probably why the car was running badly and why it was parked 5 years ago. Should get them installed tomorrow or Saturday, maybe it will even start??

Georges1991 Reader
4/18/20 12:03 a.m.

Hopefully! Sounds like it should help a lot anyway.  

yupididit GRM+ Memberand UberDork
4/18/20 12:39 a.m.

100 bucks! 

I'm following this!

Just looking at that engine shot is intimidating.  But it looks like you're on the right track.  Have fun!

noddaz GRM+ Memberand UltraDork
4/21/20 1:35 p.m.

It has been days!   What happened with this?

BrianC72gt (Forum Supporter)
BrianC72gt (Forum Supporter) New Reader
4/21/20 2:11 p.m.

Do you still need to whack the fuel pump with a mallet to get it clicking away again?  I think they had some form of points in there on me old 72 MG BGT.  Reminiscing aside, I'd want to confirm fuel pump output, FP relay and pressure regulator .  And those are hoses you want to change BEFORE they start leaking.    This model is really growing on me.  Yours is too pretty to restomod.  Best of luck.

4/21/20 8:15 p.m.

Had one of my own, I can probably help you out a lot.  First download Kirby Palm's book as mentioned above.  It lists every single known issue with these cars as well as both the right way and the cheap way to fix it.

One common problem that was actually caused by maintaining your car TOO well is a plugged radiator.  Not only is the "two-and-a-half pass" design goofy to begin with, but the A bank is what suffers from a lack of flow, but the B bank is where the temperature sensor is, so you'll never know you're overheating!  Couple that with the fact that the owner's manual states that a jar of leak-stop should be added to the coolant with every oil change.  That's a lot of leak stop, from new.  So it just fills up the radiator.  

So now you have a ton of crap crammed in under that baking hot overheating hood now.  All your vacuum lines (look UNDER the passengers' side manifold) will need to be replaced, and when you pulled your fuel injectors, you could probably hear the crispy wiring harness breaking apart.  That's the #1 cause of rough running.  All the wiring under the hood suffers, but the fuel injector harness worst of all.  Repros are available, not cheap but definitely worth it.

Good luck and let me know if you have any questions!


4/22/20 10:44 a.m.

Good luck! Looks like your car already has the air injection removed, I would remove all other non-essential vacuum plumbing. It is supposed to improve idle stability under changing load conditions, but really adds vacuum leak points. A word of caution - the short hoses between the rail and injectors are barb connections without clamps. With age they get dry, stiff and start leaking, especially the 1a/1b that have a 90deg bend. There are multiple solutions to that problem, so do your reserach and choose one. I lost my car to that leak.


GregMeboe New Reader
4/22/20 3:56 p.m.

The fuel pump draws from a small "surge tank" which accumulates rusty sludge, starving the pump of fuel. Kirby's aforementioned book describes the cleanout procedure. A little sock/sleeve filter is hidden within the surge tank. Replace this with the superceded filter, Jag p/n CBC5649, which offers a larger filtration area.

Welcome to the club!

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