My 1999 TD5 Defender 110 has a new head gasket but we cannot get the fuel injectors to fire. The fuel system is fully purged and fuel is present but no signal or ground is coming from the ECU to the injector solenoids. Wire loom is good and the injectors are re-installed in correct cylinders. We suspect the security system might be part of this but truck locks and unlocks normally and the indicator light on speedo is acting correctly. Any ideas??? We are stumped and we havelimited technical resources herein the States. Any help is appreciated.