xj12 not starting any ideas

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Just bought a 1979  Jag xj12 5.3 V12 4dr

Been off rd at least 10 yes

I put fuel in it, got a battery and jump leads on it , engine spinswhen I turn ignition  but not firing up?

Animal ideas where to start the elimination process? . First V12 IV owned so it looks like a complete maze under the bonnet. 

I do have some technical knowledge and can do bits and pieces. I'd like to try myself before giving it to garage

There is a fuel switch on dash which I press in? The car is fuel injection so no choke?

IV got a Haynes manual and it mentions a fuel cut out switch?


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I wonder if it is drawing up stale fuel into the engine.

Maybe worth trying some EasyStart to stir it into action and then listen out for the fuel pumps priming.

Generally, the V12 is quite reliable with the ignition and fuel systems.


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Hi Mo and Welcome to the Club,

Trevor is probably right that the fuel in the system is probably stale. Even if you have put some fresh fuel in the tank it may take some time for the old/dud fuel to clear the system from the tank to the fuel injection system and injectors.

It would be a good idea though to check that you are getting a strong spark at each of the spark plugs before doing anything else. If you're not then theres a good chance the fault is to do with the HT leads, distributor or coil(s). Next check out the air supply and clean/replace the air filter. The filter will attract damp if the car has been standing for a long time and may not be letting air flow effectively to the intake manifold. You may also find that the air supply pipes between the intake, the filter and the manifolds have perished or even attacked or used as a home by the local mouse population - I kid you not.

If you find nothing wrong with the spark or the air supply tenth problem is almost certainly the fuel supply. For this I would strongly recommend an inspection of the fuel tank, the fuel pump, the lines from the tank to the injectors and I would urge you to replace the fuel filters as these too have probably failed/become clogged/collapsed while the car has been standing.

Not wishing to preach but the above represents the holy trinity of internal combustion engines - spark + air + fuel = bang!

Help this helps, keep us posted on progress.



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