Originally Posted by
PhilipA
Bob, It may be that your fuel pump is dying or your relay is not working as intended.
When you turn the ignition to "on" you should hear the pump start for about 3 seconds then a click as the fuel is turned off. AFAIR on the old L jets the relay has the timer in it. In a 3.9 the ECU controls the timer. So if it does not do it you may need a new relay.
The fuel then resumes as the engine starts. This is controlled by the flapper lifting as air passes through. You can check by having the ign on and lifting the flapper a little and see if you hear the pump start. BTW my memory of this is from installing an early "federal" system to my old 2 door but I am pretty sure it applies to all flappers.
The other thing to check is the inertia switch, which AFAIK is under the passenger seat. If the inertia switch is "up" then fuel is cut off. Maybe bridge it to see if it is the problem.
It also may be that the pump is just old and tired. My pump was noticably slower to prime the injection and sometimes took 2 goes. You can hear a change in pitch in an old pump when the rail is pressurised. A new Bosch pump from a Commodore will fix it, so see the project write up.
Regards Philip A
