my raptor fuel pump stopped putting pressure out about 3weeks ago. the motor runs fine but no fuel pressure is read from mechanical and electrical gauge. checked voltage and it is good at 8.5 volts without starting it. the motor turns and there is no suction on inlet. so i told airdog about it and they shipped me a new one. i just installed it, and there is no suction. it will not prime. 2 spinning pumps, so what the heck am i doing wrong?

thank you for offering to talk to eric, but i wired a relay harness and installed it this morning. the truck works great and starts quick and smooth. will still let pureflo know that even though it is in factory engine mounted position, they need to provide the harness in order to save people from waisted timed, and maybe a burned out ecm.

Oh.....you didn't mention that you had the Raptor "FRRP". That makes a difference. Yes, those tie into the ECM just as the OEM lift pump does.

I'm not sure what you mean because I purchased my Raptor directly from Pureflow a couple years ago and the wiring harness they sent me was exactly as Mike stated. The ECM only tells the Raptor when to pump but the Raptor gets its power directly from a 12v source. Why would yours be any different?

mine is the 100 gph factory position mounted raptor....they tell you to plug it right in to factory ecm power plug.......it will not prime well with the lower speed that the 8.4 volts the ecm puts out until the motor is actually running.

mine is the 100 gph factory position mounted raptor....they tell you to plug it right in to factory ecm power plug.......it will not prime well with the lower speed that the 8.4 volts the ecm puts out until the motor is actually running.

Did you ever try bumping the starter to prime the system? The fuel pump is supposed to run for approximately 25 seconds at full power when bumping the starter but will only run for about 2 seconds when simply turning the key to ON. And yes, when cranking the engine, the ECM supplies alternating current to the fuel pump to reduce the fuel pressure.

Since i never say how my oe lift pump was connected, can one of yall enlighten me. When my oe went I took it to a dealer and they gave me the coveted in tank pump. When i installed my AD the plug for the old lift pump was just hanging there and I plugged into it. Did the oe lift pump go thru a realy? I removed one on the firewall for the intank pump but do not remember any thing plugged into the oe lift pump harness.

Since i never say how my oe lift pump was connected, can one of yall enlighten me. When my oe went I took it to a dealer and they gave me the coveted in tank pump. When i installed my AD the plug for the old lift pump was just hanging there and I plugged into it. Did the oe lift pump go thru a realy? I removed one on the firewall for the intank pump but do not remember any thing plugged into the oe lift pump harness.

The OEM lift pump connects directly to the ECM plug right where the lift pump is mounted to the frame. The ECM fully controls and fully powers the OEM lift pump. When you replace the OEM lift pump with a higher volume / higher pressure fuel pump, the ECM should connect (as some are) in a way that the ECM plug is connected to a new wire harness relay whereby the ECM is telling the relay when to allow power to the fuel pump but the fuel pump is no longer powered from the ECM but powered by a separate 12v source. I think thats what you were asking.

I was curious about the oe lift pump since i never messed with it. i did not know what powered the oe. My AD relay is connected to the oe harnes for the old lift pump to perate a relay. My power for the pump is coming form the alternator thru that relay.