vp in-tank lift pump insufficient pressure

turbojoe

turbojoe

Cummin get you some
Joined
Jan 16, 2007
Messages
742
Got a 01 vp truck and its about 5 psi at idle and any throttle it drops to zero. So I was wondering if I could mount a replacement pump on the block and leave the intank pump in place. I was wondering if it could suck through it with no problem?

Thanks
Joe
 
No, it needs to be removed or have a draw straw installed in the tank. Keep in mind a pump is built to push not pull, and you want to make it as easy as possible for it to do its job, so you want to mount the new pump as close to the tank as possible. This is also why the block mounted pumps suck so bad, and everything else has in-tank pumps.
 
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You can get away with using the in tank pump as a pusher feeding the block mounted pump. The easiest way to do that is modify the extension harness(so you don't have to splice into the factory engine wiring harness) that comes with the replacement pump so it will power the block mounted pump like it did from the factory, but also still trigger the relay for the in tank pump.
 
dont waste you time with the block pumps. Just get an airdog or fass and put in the draw straw (or sump) and call it a day
 
BrettWINspeed said:
You can get away with using the in tank pump as a pusher feeding the block mounted pump. The easiest way to do that is modify the extension harness(so you don't have to splice into the factory engine wiring harness) that comes with the replacement pump so it will power the block mounted pump like it did from the factory, but also still trigger the relay for the in tank pump.
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Except the fact that his in-tank pump is obviously getting ready to go out, so when it dies he will be dead in the water, and wasted alot of time and money.

Just do it right the first time.
 
What he said, fussed around with my buddys truck trying to save a few bucks, ended up getting a raptor and using his factory fuel filter housing and puttinga straw into the factory fuel pickup area, for the hassle, we could have done it once and saved lots of time on the side of the road
 
SPEEDSHIFT said:
Except the fact that his in-tank pump is obviously getting ready to go out, so when it dies he will be dead in the water, and wasted alot of time and money.

Just do it right the first time.
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Not necessarily on the way out, I've seen brand new in tank conversions that have had pressures that low. Most of them average around 6-8 psi, but I've seen a few lately that are up around 15psi.

He'd be into it for maybe $150 and an hours worth of time, where to do it correctly he's looking at finding a stock module(most of the used ones we've bought have been $200-$250), a Liberty module to modify his current module($150 with the $40 core that the dealers now charge), or a $300 Vulcan Performance module. There still seems to be too many low fuel level issues when adding a draw straw. Upgrading to a good aftermarket pump will be a $300 minimum(Raptor factory replacement pump). So it would be a minimum of $450 plus installing a pump/system, plus the time to install the module.

I never said it was the best option, it's just a way to make do with what he has for the least amount of time and money.
 
If you cut the draw straw the right length it wont have issues, and every in-tank I have seen put out 15psi at idle. If it drops below 5psi at WOT it needs to be replaced, I don't care how new it is. A Raptor with draw straw kit would be $325, then he can just leave the old module in the tank, no need to replace it.

JMO on doing it right though, I always revert to a saying an old man I know used to tell his customers...

"You never have enough money to do it right, but you will always have enough to do it twice"

:D
 
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