Replaced fuel pump

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01Indian

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I replaced the fuel pump with a VPHIX on an 88 Sierra, original pump was putting out 6psi. Now new pump won’t kick on, while applying power with a power probe to the new pump it kicks on, volt meter shows I have 12 v on the harness side while primed but only for a short time 5 sec maybe. After replacement truck just cranks. Help?
 

PlayingWithTBI

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volt meter shows I have 12 v on the harness side while primed but only for a short time 5 sec maybe.
That's normal. When you turn the Key On Engine Off the ECM will run the pump for 2 seconds to prime the system. When you're cranking, the ECM will see Distributor Reference Pulses (from the ICM and Pickup Coil in the distributor), run the pump and fire the injectors. The Oil Pressure Switch on the China Rail will also run the pump as a backup to the Fuel Pump Relay.
 

Caman96

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What about the sender, was that replaced? Just did mine and before I installed sender/pump I gave quick test to verify it worked. Didn’t want deal that after installing.
 
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