So I installed a holley blue fuel pump on the rex this weekend, and no matter what I do the regulator will not adjust to a lower pressure. It stays at 9 psi no matter what I do with the adjustment screw.

Its a Jegs bypass regulator JEGS Performance Products 15909 JEGS Billet 2-Port Adjustable Fuel Pressure Regulators

I have already replaced the diaphragm in the reg... no changes.

It doesnt leak, the return line for the fuel tank is hooked up, and it doesnt seem to be flooding the fuel bowls even at 9 psi...

Any clues as whats going on here?

Its a RB 465 too btw.

 

It seems my return line is too small, or clogged...

I removed the return line and let it free flow into a bucket for a few minutes of the engine running. The fuel pressure dipped to 3 psi and allowed me to adjust it up and down from around 4 psi all the way to 12.

Has anyone else had to run larger return lines for a holley fuel pump, or do you think mine are just clogged?


I can blow into the return line and move fuel in the line without a lot of effort, but its far from free flowing.

 

?

 

I had that problem with mine too, the stock line size should be good enough, most likely the line is clogged a bit. I ran a new return line same as the stock size from the regulator to the tank and it fixed mine. If you have a few extra bucks might as well just upgrade the lines if you're going to be down there running a new line anyway.

 

Do you have an SE fuel system? My Mallory unit adjust down to 3psi or even lower with the factory EFI pump and return line, rock steady fuel pressure.

 

max inlet pressure of the mallory is 20 psi...

 

If the return is the original for a nikki then it check to make sure the restrictor is not still in there.
The stock return for the nikki has a restrictor in the hose that helps maintain pressure to the
carb when the stock pump is used.

 

Im guessing said restrictor is in the engine bay? Or is it on the chassis?

 

It is in the engine bay. Located where the return line is hooked and a metal line on the fire wall. Also if you removed it it could have been installed backwards (has been know to happen). The owner of my first FB did that and could,"never get it running right after he rebuilt the carb".

 

yeah that entire rubber hose was replaced so there is no restrictor.

holley phoned me back today to tell me that a 3/8 bypass is required for the blue pump. the stock return line is 1/4