walbro external fuel pump and wix corvette filter/regulator

[87squarebody]

I'm helping a buddy with a 5.3 Vortec ls swap on a 85 c10.We have a 85 fuel tank and are using the walbro 255 external pump and the Wix 33737 corvette filter/regulator.We put a fuel gauge on the fuel rail and just hooked up a power and a ground to the pump and the fuel press pegged the needle on the gauge over 125psi.Shouldn't the fuel pressure regulator keep the pressure at the rated 55to60 psi.It is all brand new im thinking we have a defective regulator or are we over looking something.Thank you guy in advance.

[truckdude239]

How is the filter pumped? 3/8line is feed 5/16 is return filter should keep pressure at aroun 60 mine does using the wix filter regualtor

[87squarebody]

Yes thats they way its plumbed.But for some reason the fuel pressure at the rail pegs the fuel pressure gauge over 125psi.Would not having the fuel pump wired through the stand alone harness fuel pump relay have something to do with this.I wouldn't think so but I could be wrong?

[ls1nova71]

Post a pic of how you have the lines hooked up if you can, it sounds like something is backwards. The 3/8 male fitting on the filter should be the feed "in", the 5/16 male fitting should be the "return", and the 3/8 female is the "out" to the fuel rail. If you have it hooked up that way and it's still pegging the gauge, you either have a bad filter/regulator or a defective gauge. I have seen cheap filters be bad out of the box, but never a Wix, does the filter have "Wix" stamped on it? Maybe a cheap one got switched to the more expensive Wix box, shady things happen.

[87squarebody]

We double checked the the connections and all is right.Going to get another wix filter/regulator and put on this week.By any chance would the pressure be that high due to just hooking up direct power and ground and not going through the fuel pump relay in the stand alone harness.From my understanding the crank sensor sends a signal to the computer which then sends a signal to the pump making it come on when needed.I could be wrong this is all new to us as it is are first swap.My truck is next its a 87 so the fuel system will be different my motor in not returnless.

[Daaaanz67]

The wix filter will regulate the pressure, your still only supplying 12v to the pump even if your not using the relay.

[chuckmc8]

It sounds like the fuel return line from the regulator to the tank is somehow stopped up or plugged.

[Wasted Income]

Could be a bad filter/regulator assembly. I've gotten more from WIX that were junk straight out of the box than I care to remember...but it was the other way around. Just enough fuel pressure to idle, and nothing more.

[Justin@EntropyRad]

can you pull vacuum off the rail and see if pressure changes?

[87squarebody]

So we found the problem!The sending unit had a filter on the return tube on the inside of the tank restricting the flow.This is a brand new sending unit.

[ls1nova71]

Originally Posted by 87squarebody

So we found the problem!The sending unit had a filter on the return tube on the inside of the tank restricting the flow.This is a brand new sending unit.

That part is on the vent tube inside the tank, are you sure you had the return hooked to the right line?

[87squarebody]

Yes it is connected right.We took the return off the tank and dumped it into a gas can and the pressure was 58-60psi.We dropped the tank pulled sending unit and found it so we took it off hooked it all back up and pressure was good.So definitely that was the issue.

[cagodinez]

Bringing this back from the dead, I'm having exact same problem, going to pull bed this weekend.

[87squarebody]

Originally Posted by cagodinez

Bringing this back from the dead, I'm having exact same problem, going to pull bed this weekend.

Yeah check the sender on the return there is a small plastic filter that restricts the return.That was are problem
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[cagodinez]

Thank you 87squarebody, that did it.

[87squarebody]

Originally Posted by cagodinez

Thank you 87squarebody, that did it.

Sweet glad I could help.
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[87chevy.com]

Oh my bmw ls swap, I had a corvette regulator crap out after 2000 miles... decided to machine down a 4 bar regulator and use the bmw filter which has 3x more filter media.




Clint

[TooTall]

Originally Posted by 87chevy.com

Oh my bmw ls swap, I had a corvette regulator crap out after 2000 miles... decided to machine down a 4 bar regulator and use the bmw filter which has 3x more filter media.




Clint

any more pictures ? how did you machine it down?

[87chevy.com]

Originally Posted by TooTall

any more pictures ? how did you machine it down?

Just shows it machined down to fit the filter.