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Need help! Fuel pump trigger

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Old 05-27-2020, 10:20 PM
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Staging Lane
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Default Need help! Fuel pump trigger

I'm new to this but I did search and couldn't find exactly what I needed.

I have a 04 5.3 i swaped into a '53 Cadillac. I Did the LT1SWAP.COM wire harness conversion. We went to start it for the first time and I'm not getting a signal from the ecm (green #9) to trigger the fuel pump. I check continuity and there's no breaks in the wire. I sent the ecm to a local tuner to disable the VATS.
what kind of voltage should I be seeing from the wire when I turn the key? I'm not seeing anything.
what am I missing? Could the ECU be bad, could the VATS still be enabled?

I need help here, I'm so close......i think...... to cruising this thing.

thanks!
Old 05-28-2020, 05:14 PM
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Are you running the wire directly to the fuel pump or using a relay?
Old 05-28-2020, 06:48 PM
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I'm using a relay. I checked it with 3 relays and neither one activates.
I tried checking voltage on the the signal wire from the Ecu and I'm not getting any voltage.
I'm going to make sure the ECU is getting voltage tonight.
Old 05-28-2020, 08:14 PM
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Don't forget, when you turn the key on the pump will prime for about 2 seconds then shut off 'till it sees the engine cranking. So when checking the trigger, do it within the first 2 seconds or crank the engine while checking.
Old 05-28-2020, 08:14 PM
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I would start by disconnecting pin 9 from relay coil. Apply 12v to relay coil and see if relay and fuel pump kick on. If that all works reconnect to pcm and check ALL pink pcm ignition hots to make sure they are all getting power. Also check ALL constant hot wires and all pcm grounds to make sure you didn't miss any.
Old 05-28-2020, 10:19 PM
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Found the issue. The thermal the fuel pump fuse plugs into wasn't clipped into the fuse block. So when the fuse was put in, it pushed the terminal down, instead of clipping into it.
it fired right up but now I have a CEL on and low oil pressure light on.



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