I switched from TBI to carb about 2 months ago. I am running the Mallory 4309 Fuel Pressure regulator. I have everything connected and it has been working ok. Last week I noticed that fuel has started to leak out of the Boost Port on the regulator. Could this be a bad diaphram in the Regulator? It seems to hold pressure fine at 4psi. I can adust the pressure up and down fine but still have gas coming out of the boost port. Any help is appreciated.

 

Sounds like the diaphragm is torn.

Jegs carries new ones #3156 at $25 IIRC

 

Thanks for the response. I checked the diaphragm and it was leaking. I got a new one from Summit. Just as an FYI for everybody. The new diaphragm is a little different and I needed to make up a spring to get the pressure under 10 psi. I think maybe the spring that was in it before was the high pressure spring but the diaphragm was always leaking so I could get the pressure down to 5 psi. Mallory says that the new diaphragm will not work for 12-60 psi any longer. Thanks.