Hi XJS lovers,
For about 7 months I've been the lucky owner of a wonderful '85 XJ-SC V12 5-speed with TWR mods.
One of the problems from the day I purchased her was that she is hard to start. She will spin on the starter for 10-15-20 seconds, and needs a bit of a pump of the accelerator until she finally fires up.
She has never failed to start, but whether cold or hot, it's always the same.
Jag mechanic that has services Jags for many years suggested switch key on to prime the fuel pumps a couple of times before starting, but that doesn't make a difference.
There is obviously something that needs an adjustment, but I just don't know what that is? She idles fine, accelerates without a hiccup and behaves beautifully once started.
But I just don't know what to hunt for.
Appreciate any ideas.
Thanks,
Adam

 

Looooooong list.

Depending on what Walkinshaw "modded", probably not much in the real world.
I would read my sticky at the top, No star.......

Same check list.

TPS out of range.
Resistor pack (RH inner wing near the radiator) has really GRUBBY terminals in the plug and socket
Spark plugs need to be NGK BPR6EF, thus putting the spark out in the bang juice, as apposed to the standard sparkers that have the spark almost shielded.
Sparks gapped at 0.025" and NOT near enough.
FPR, the B Bank sucker is bleeding off. The A Bank FPR should be removed, PDF for that if you want/need it.
Engine earth strap fiasco at the LH engine mount is in fact earthing, most are NOT.
Ignition switch is still supplying 12v to the White coil wire during cranking, most are NOT.

That lot will keep you out of the pub for a day or 3.






Check the spark. You need a FAT BLUE RACKER, at the plugs

 

Hi Grant,
Thanks so much for the suggestions.
I will need to work through your suggestions slowly and methodically. (Still learning about this beast).
Can I ask what "FPR" is, please?
Also, I can see where the spark plugs are. All of the reading about the access (or lack there of) for these plugs in HE cars is daunting.
I will get my hands dirty with it over the course of the next couple of weekends. (Strangely, I seem to obtain cars with "hard to get to" plugs, except for the XJ. On the RR, to change the plugs you need to jack up the front of the car, remove the front wheels, remove the inspection plates inside the wheel wells and then with your very articulated arm and a multi-direction socket wrench, you can get to the plugs - being a V8). The V12 looks to be a bit of a tease.... you can sort of see the plugs and / or know where they are, but they are "just" out of reach.
Fun times ahead.
And yes, I have already read a number of your docs and will go over them again. They are brilliant.
Thank you,
Adam

 

FPR is Fuel Pressure Regulator. There are two, one on each bank. The one on the B bank does the actual work. I can't remember why the A bank one is there, but it doesn't need to be.

 

Hi Grant,
Just found the acronyms document you posted / shared.
I asked too soon, before RTMF / RTFM. (I'm in the IT industry and RTMF refers to "Read The Manual First" or my favourite version "Read The F***g Manual".
Thanks again,
Adam

 

HA, Spare Parts my whole life retired at 70 (3 years ago), minus 4 years pedalling a Road Train around the Island.

Spark plugs, first time, about 6 hours. NO shortcuts, remove stuff for access, the #1 on both sides will test your sense of humour and make the RR look easy. Loosen and pack UP the A/C Comp makes it a "little' easier.

Watch the distributor cap for both #3 sparkers, as a slight slip of the socket bar and you will crack it, FACT.

#6A, oil switch will slice your hand, JW Blue helps there.

BUT, there is always a BUT.
CLEAN THAT V 100%, then do it again. Anything you forget or miss will go down that plug hole, guaranteed, then its engine out for rectification.

 

Compresed air squirted down the plug well before you remove the plug to blow out any debris!

 

Hi Greg,
That's a terrific suggestion, thank you!
Will definitely do this.
Regards,
Adam

 

Well worth renewing the coolant temp sensor for the ECU, located on the B bank thermostat housing. If these fail the car will not start. Check tthe loom that connects to this for brittleness and if cracking cut back the wrapping until you find flexible insulation and renew the bad part. Same with Air Temp Sensor on B abnk air inlet trumpet.
Explained a bit here;

https://www.jaguarforums.com/forum/x...chment-265177/