Surging of power 7.3 non turb,91 f 250

[Abuckhunter]

Hi All, I have a 91 250 7.3,I have been having alot of hard times with this truck all air I think,anyway as I said going down the road and I get power surging ,I put ALL new return lines,and new washer at inline from lift pump when I put in the new lift pump,I also put in a elec fuel pump just infront of the tank swith ,but I am not sure if the elec pump will help if I still have a lift pump ??? should I take out the lift pump ??? and how can I find the air getting in ??? one more thing are there any tricks anyone can offer for changeing the seal at the rear where the driveshaf goes in to the rear any tips are welcome. thanks so much for your time.

[cdnsarguy]

Welcome to TDS...

First never run both fuel pumps, just have only one in the line. You can remove the manual lift if you prefer, get a BB chevy blockoff plate to cover the hole. Check to see if the electric is pumping when the engine is running......what is the GPH and pressure of the E pump.

Do you mean the rear axle pinion seal....

[Abuckhunter]

Hi thanks for the reply,the elec pump is 5 lbs,by never run two pumps do you mean don`t run elec and lift pump ? as far as the seal,its the seal that keeps the rear oil from coming out around the driveshaf at the pumkin,

[cdnsarguy]

Only have one pump in the system is my advice... The lift pump will work all the time engine running, the electric when powered. If the electric is not powered it is a blockage for the lift pump to overcome.

You may have air leaks at the electric pumps connections too ......surging.