So I went away on a long trip, and with the thirsty old big block under the hood I was forced to use both tanks...

I made it where I was going on the front tank, and then switched tanks about halfway home... She ran like a champ the whole trip.

Thing is, I went to start her the other morning on the rear tank, and she cranked, then stumbled sputtered for a few seconds and ran rough for a second, then purred like a kitten...

So I thought maybe the line wasn't holding pressure, so the next time I started it (a day later) I tried "priming" it by cycling the key on a few times to let the pump pressure build. Still did the same thing...

It SORT of does this when using the front tank as well, but only if the truck has been sitting for a day or two. But with the front tank, it just has to crank for about 3 seconds before it fires up,(no sputtering or anything) but if it has been drivin within the past day, it will fire as soon as you hit the key...

Any ideas??? I'm just gonna go back to using the front for now, but I would like the rear to be working properly so that I can swap between the 2 in order to keep both tanks fresh, and keep the pumps etc moving...

 

crap in the tank clogged filter?

 

I would assume its running a electric fuel pump, I had this problem on a car once and I just would turn the key to the on position and wait for the pump to re-prime the system before I would turn it over to start.
I never had any leaks, but for some reason that car would loose that good fuel prime over a day or so of sitting also.

 

I had the same issue. First hard starts, some stumble. Then it won't start unless you do several "primes". Then it just won't run on that pump. I changed the pump out (and tank as it rotted) and all is well.

Mine also reached the point where switching tanks while driving resulted in the motor stalling. At first a switch-over caused a stumble but after some time the engine would just stall.

 

Possibly, but you would think that would cause issues all the time, not just on startup...

Yeah, even priming doesn't seem to eliminate it... just odd that after running it is fine on restarts...

Yeah, its likely the original pump... hopefully it keeps going for a while... Really don't feel like dropping the tank

 

I guess the easiest way to see whats going on would to be to put a pressure gauge on the fuel rail, and see it it is bleeding down after 24 hrs or so?

 

Just pull the bed. That's what I did.

Mine will start rough on the rear tank (and lately I've been starting it that way on purpose so that the engine doesn't rev to 1500 on a cold start) and will drive alright but lacks power. Rear fuel pump is on it's way out...ain't confirmed it with a gauge yet but I really don't need to. Runs great on my newly installed pump in the forward tank, so that rules out regulator and filter problems.

Bleeding pressure down overnight means the check valve in the fuel delivery module is leaking.