I bought a 1986 Jaguar XJS V12 only It does not have the V12 I believe it has a 305 or 350 Tbi 5.0. I changed the fuel pump in it I changed fuel filter I changed the spark plugs and the wires I've tried to crank it over it fired up once but then quickly died further inspection I noticed that there was a lot of fuel on the top of the engine and when you put the key in the on position but not quite crank it over fuel continuously comes out of my fuel injector and I have no idea why I've changed the fuel injectors and still I have the same issue just lost his anybody have any input

 

It's hard to advise, as you don't have a Jaguar engine and not many people here have experience with foreign engines. It has to be a gasket, o-ring or fuel line connection somewhere. Maybe go to a junkyard and get another TBI unit? You can also get overhaul kits on Rockauto for not a lot of money.

Is it possible that there is an electrical fault that is firing the injector all the time? I have no idea how those systems work though.

 

Hard to imagine what is going on from your brief description, but I think it will really help to figure out what this lump came out of in the first place so that you can find a shop manual to help with diagnosis, maybe research/ask questions in the right make/model forum, and more critically, so you can order the correct parts to repair it. Hopefully the block hasn't been decked or otherwise original vehicle identification removed (i.e. stolen), but you should be able to find and write down the VIN number stamped on the engine block and enter in the GM online parts catalog and/or use casting and date codes, then search the web for clues. Here is a starting point:

https://hotrod.gregwapling.com/monar...8-engines.html

 

Follow the passenger side valve cover to the front and look down where the head meets the block. There's a flat stamped with engine vin number/suffix code as pdupler indicated. Post the numbers.