1979 Jaguar XJ6 engine cranks but won't start

Check to see if the ignition relay is good then check fuel pressure with a gauge autoparts rent it. If you have the luca distributor with the amplifier on theoutside then those are known to be bad and shold be replaced either with a crane or petronix ignition system both about $150 u.S. Check fuel pressure shold be 36.5 psi. If not may be a bad pump, regulator, filter etc. It is quite involved diagnosing the fuel injection so if you wan tto do it your self get amanual