Update , have disconnected each injector in turn on this jeep and when inj no 3 was disconnected it started and ran on four cyl for about four seconds , connected inj back up and no start have tested wiring from ecu to inj no 3 and all ok no short also tried an injector ( just plugged in )and still non start ! soon as inj disconnected it runs briefly , seems like there is a capacitor problem inside ecu but this was tested under load and passed ! is ecu shutting eng down because of a major misfire when disconnected ????
Regards John