Low Fuel Pressure - Custom Tank in LS1

[162hotrod]

Folks: Need some help!!!! Just tried to start my LS1 in my 62' Impala Wagon. It is a 2000 LS1 with Street and Performance set-up. I have a Walbro submersed pump in a custom aluminum tank built by Doc's out of Georgia. I am only getting about 4-6 PSI of fuel pressure at the fuel rail. Motor obviously won't run with that kind of pressure. You can hear pump run but just isn't putting out enough pressure. Brand new S&P in-line fuel filter and -6 AN fuel lines all the way to motor. Any thoughts? Help! Need to get this ride to the body shop for its two-tone paint job! Thanks in advance.

[KMdef9]

Pinched line or clogged filter is where I would inspect first.

[Knight]

First, I would check the fuel lines for any kinks, causing poor flow. If all checks out, the next thing up would be the pump and regulator. Is this the first startup? I have heard of an issue of reversed wiring on the pumps, causing low pressure or no pressure. You might try reversing the leads and check the results. If that does not solve the problem, then it would be the pump/regulator.

[162hotrod]

KMdef9- the fuel filter is brand new. Unless there was tons of sediment in the new tank I wouldn't think it would be clogged. Knight-if the power wire was switched with ground would the pump even run? I might have it switched but the pump does run.

[KMdef9]

KMdef9- the fuel filter is brand new. Unless there was tons of sediment in the new tank I wouldn't think it would be clogged. Knight-if the power wire was switched with ground would the pump even run? I might have it switched but the pump does run.

Could be buildup in the lines as well. Stranger things have happened. Just as easy thing to check.

As far the wiring, it will run the pump motor in the opposite direction its intended to. Which will still pump gas, just not ideally. Think of running an impeller backwards, it will move fluid, just not nearly as strong. But that depends on the type of internals of pump, which I am not positive if the walbero is like that.

[162hotrod]

Hooking it up backwards wouldn't burn the pump up?

[KMdef9]

Hooking it up backwards wouldn't burn the pump up?

It could, that depends on the specific product. You could contact walbero and ask what happens.

A lot of electric motors work like this; if you feed positive voltage to one side of the motor it was spin it clockwise or counterclockwise, then if you feed positive voltage to the opposite side, it was spin it in the opposite direction. Which can burn them up, but not necessarily right away. But I'm not sure if that's how the walbero works, they would know best.

[162hotrod]

Thank you so much for this information!!!! You don't know how much I appreciate it!

[KMdef9]

Thank you so much for this information!!!! You don't know how much I appreciate it!

No problem.

Just to be clear, sometimes I confuse myself;

We weren't recommending you just simply switch the wiring, I would check if you did and contact walbero before you do if your still unsure.

[162hotrod]

Thanks. Will do.

[Knight]

Thanks Kevin. Had to jump out for a bit. There was another thread a while back that was the same problem. It ended up being a miswired pump. I can't recall, but I think it may have been on the manufacturer's end. Figured I throw it out there as an option.

[Knight]

Here's the thread - http://www.ls1.com/forums/f6/new-rac...umping-161828/

[Smittro]

Do you have enough outside air flow going into the tank?

[Smittro]

Oh and what type of regulator are you running?

[SMWS6TA]

don't you have to use a -8 AN fuel line instead of -6 AN?

[162hotrod]

Folks: Wanted to thank everyone for their suggestions. Found the problem last night. Double checked the wiring and positive and negative were correct. Dropped the tank and the rubber hose running from the pump to the module at top of tank was barely attached. When I touched it the hose fell off the pump. So I put the hose back on and tightened the clamp. This problem was from the installer of the pump in the tank which was the company that built the tank. I will not say anymore about that installer because I guess it could happen to anyone. A simple mistake that caused a whole lot of problems including having to remove the tank and pump which amounted to about a 4 hour job.
I haven't put the tank back in the car yet so I am hoping this was the issue. One thing I noticed was that the pump was secured to the bracket in the pick up by a plastic "zip tie" Thinking I need to change this too. Any thoughts on the expected life of the zip tie in gasoline? Thanks again to everyone who offered suggestions.