Got rained out at work (concrete finisher) so I put on my lift pump. Everything went well ,I bled out the air above fuel filter. I dont know if it is my imagination or not but the small leak at the fuel heater turned into a bigger leak. I am assuming that the new pump is holding the correct pressure and not bleeding off like it was before when it leaked causing more pressure thus more of a leak.I have the parts to fix the fuel heater leak arriving tomorrow from cummins. The big question is do you think i will gain any better throttle response,horsepower,or fuel mileage.

 

Not being a smart-tail or anything, but fixing the fuel leak will improve the MPG numbers alone.

Assuming it is/was a small leak then you may not see any improvement otherwise. Then again, if the old lift pump was marginal at best then perhaps you will see a small top end improvement simply due to no longer going to 0psig fuel pressure to the IP at WOT.