Lift pump just failed
Hi, I've been following all these posts and since my second factory lift pump just failed, I figured I'd add what I saw. I have a SPA fuel pressure gauge that will show vacuum as well as pressure. When it first started the gauge showed -3 then fluctuated back and forth between -4 and +5 (it usually would run about 9 while cruising) as I was pulling over the gauge went to -11 and the truck stalled shortly after. I coasted to a stop, turned the key off and on, lift pump ran, gauge showed +11. Shut it off waited a couple of minutes, turned it back on, gauge showed 11 again, fired the truck up, idled fine, showed 10psi. Started to pull away, gauge went to negative numbers again. Pushed in the clutch, gauge went to 9. Got back on the power, gauge went to -11 truck started to stall, pushed in the clutch gauge went to -3. Pulled over and called a tow truck. As I was waiting for the tow truck I turned the key on several times, gauge always showed at least 7psi. I checked all my fuel lines, all were tight, no leaks anywhere. What I don't understand is this: when the lift pump goes bad wouldn't it just plain quit working? Mine was supplying enough fuel to idle but not much more. This also throws a monkey wrench into the theory that the VP44 will draw fuel from the tank through the filter. When my gauge showed negative numbers, the truck really stumbled and shortly after died.
So my idea is to upgrade the fuel lines to 3/8" using custom straight thru fittings at all ends which I am currently having machined. And I am going to install the new factory lift pump I have on the frame close to the tank. My truck is near the 400hp at the wheels mark and probably won't go much higher. Does this seem like the solution or am I way off base?
Sorry for such a long post, just thought my findings might help.
Thanks,
Jerry