engine won't start.

[Stevecharles]

Hi. just put another engine in my megane2.1.5dci.got everything connected. Turns over nicely but won't start. Know an ex Renault mechanic who has the computer and he connected it to the car. Everything coming up fine except no reading from fuel pump. Put a special light onto one of the connectors to an injector which should strobe when pulses are sent to injectorwhen I turn the engine over. What's happening is the light comes on when the ignition is turned on. Then when I turn it over the light is intermittent not a steady pulse. Any ideas? Thanks.