I have a 1981 Jaguar XJ12 V12 (5.3L) car was made in febuary of 81 and I am certain it is pre-HE. The problem I am facing is overfueling badly the exhaust fumes make my eyes water and I think there is now gas in the oil, bumper is also black with soot. it has 60,000km on it. All stock except the P.O put a Crane Cams Fireball ignition on it, model # XR700 and he told me that he could not get injector pulse then when i went to pick it up he had ran a wire from the ECU to the coil and now it runs but it runs very rich. Do you think it's the ignition? I have no idea as to why it runs with that wire but not without, thanks in advance for any help

 

Check the coolant temp sensor.


See this link for more info...
https://www.jaguarforums.com/forum/x...-sought-33273/


Check the air intake temp sensor in the case of the driver side air cleaner, typically comes disconnected or suffers a broken wire.


Check the vacuum hose that T off the manafolds and go to the MAP sensor located on the radiator support. Make sure the hose is not leaking and that you have a good vacuum signal.

 

Check these too...
Ignition Amplifier Replacement
JAGUAR V12 FUEL INJECTION 1975-1980 - D Jetronic / AJ6 Engineering


Check the Fuel injection trigger board in the dist. What exactly is the wire from the ECU to the dist? If its give 12 pulses every 4 revolutions it's too much. I think the Fuel injection system, is a batch fire two pulse system and the fuel injection auxilary amp splits it across 3 banks for use on the V12.

 

the wire goes from the ECU to the Coil not to the distributor