2007 Injector failed, ECM shut down fuel pump?

[smokymtn65]

Put in a cheap set of injectors while oem units were being sent out to be rebuilt. One failed was flooded engine shut it off. Did know wha was happening at the time. Had truck towed home. Was doing a fuel pressure test but the pump acted dead. Tried to comand it with scanner, nothing. Tried swapping relays, nothing. So pulled relay and jumped with hot wire and pump worked. Did not hold pressure so pulled injectors and one was free flowing. So bad it full cylinder was gas, pulled plug and drained it. So question is, will pulling battery cables reset ECM or what cause the intruction signal to pump relay?

 

[j91z28d1]

what year truck? these don't really have relay to send power like the older stuff. there's a fuel pump module that sends a pwm ground to the pump to control fuel pressure since they dead head into the rail.

if you command it on with a scanner it should come on no matter what?

 

[smokymtn65]

2007 , 5.3 LC9

my thoughts exactly on the scanner.

 

[j91z28d1]

interesting... just took a peak at a wiring diagram for a 07 5.3. it just said engine code C or J. but both showed normal relay controlled by the ecm. must be a return style system. I didn't know gm kept using it into these body styles.

85 is the ground and 86 gets power from the ecm to turn on. 30 is hot at all times, 87 runs to fuse #20. it's after the really, so it only has power when the relay is on.

maybe check that you have power at terminal 86 when you command it on with the scanner.

 

[smokymtn65]

I will do that tonight, have the fuel rails off right waiting on injectors, so will have adapt a guage onto the end of fuel line.

 

[smokymtn65]

Update: did not get to dig any deeper before i received my injectors back. I disconnected the battery, Installed injectors, put everything back together and reconnected battery and hit the key and pump works. So apparently the computer will shut off fuel pump if it freeflows to much or to long.