lift pump operation

[kanui]

Is the lift pump supposed to operate when the key is turned on? I just changed my fuel filter and put a clear plastic hose on the bleeder and put the key on the "on position" and nothing happen..no noise from the lift pump and no fuel coming out of the clear bleeder hose. If the lift pump is not working...does the engine still run? This one does run...I have not tried to start it though since changing the fuel filter.

edit: I just read an article that said the juice for the lift pump is cut off if there is no oil pressure. Does this mean you people have modified your lift pump to come on when doing a fuel filter change or is there some other means that I can get the lift pump to come on so that I can bleed out the air? Pay pal 5 bux for an answer in the next 10 min


93 chevy 3500 6.5

[Kennedy]

The lift pump and the Oil PSi cutoff switch are two major sources of 6.5 problems. Because of this we offer a complete control harness to take over operation of the lift pump. It has a prime to start function that runs the pump briefly at key up along with an oil psi safety switch and manual push button. The oil psi switch in my harness does not carry any load, only carries signal to tell the circuit to energize.


With the earlier models you may need to lengthen the supply wires a bit depending on where you mount the control, but the kit is basically universal.

http://www.kennedydiesel.com/detail.cfm?ID=402

[bobt]

On the '93, the lift pump does not run when you turn the key on. Sometimes the pump will run for a short time after you turn the vehicle off.
Bob

[Robyn]

On your truck, the lift pump is wired in with the starter solenoid circuit and will energize when the key is in the "CRANK" position.

Once the engine fire off and oil pressure builds the oil pressure and the lift pump runs continuously.

The Oil pressure switch has the sender to run the gauge and a set of contacts that run the lift pump.

The oil pressure switches are prone to failure due to the load placed on them.

The later trucks Post 95 run the lift pump with a relay that is controlled off the ECM.

If the rig has lots of miles, its a good idea to replace the Oil pressure switch.

Johns Kit would be a great addition.


Best

Robyn