THETANK

Does this look like the proper location for the fuel pressure gauge? It does not seem like it would be measuring the pressure going to the carb in it's current location. I am trying to determine if this is why my FP is reading high.

camaronewbie

Is that another pressure regulator attached to the bottom of the 4309?

That would be the right spot.

For the return line, did you make sure to use 5/16 diameter stuff? You have to have a solid 5/16 inside diameter for the return line - anything smaller or obstructing that will make the fuel pressure higher.

That's why I asked about what's attached to the bottom of the 4309 - your return line should attach there - if you have another regulator there, it's restricting retrun flow, thus making your fuel pressure too high.

THETANK

Yes it is another regulator. I had an engine built/ installed and the "mechanic" rigged the additional regulator (the red one I supplied the Mallroy) up b/c he said this is what I needed to make it function properly. My FP is too high now and I am getting a fuel leak around his regulator (where the blue AN fittings are). Basically now I am try to fix what he did.

camaronewbie

I'd start by removing the extra regulator. The return flow must NOt be impeded in any way - the Mallory unit adjusts the return flow (not the flow to the carb) and thus if you are changing flow on the return side by use of the extra regulator, then you are increasing fuel pressure to the carb.

If in the event that you need to regulate down farther than the Mallory will do on it's own (I can't see this as a possibility, but anything is possible), then you'll want the extra regulator between the Mallory and the carb, not on the return side.

But first, I'd take the extra reg out, and see what I got with just the Mallory - many of us use only the Mallory with no issues.

vetteoz

iTrader: (13)

I don't see how that setup works.
The relief side of both regs is joined together so you have NO bypass at all

You are seeing pump pressure at carb because even when the 4309 bleeds off pressure it has nowhere to go so you are dead heading the carb from the pump
As it is now ;
if supply line is to the 4309 then it bypasses fuel to the OUTLET side of the other reg so fuel is going nowhere except carb .
Bet you could take line off red reg and there would be no fuel coming out

THETANK

I think Fuel is passing through the second reg b/c I had fuel leaking ( see pic) from this area. So you think if I were to remove the red reg and attach the return line where the red reg was that would solve the problem.

Damon

Yes. That setup is bizarre. You use ONE regulator to get the job done, not two in a row.

Even if it's boost referenced (the Mallory has a boost reference port- the little hose nipple you see sticking out the side) you still only use one regulator.

Could very well explain your high fuel pressure.

vetteoz

iTrader: (13)

Even if you stacked multiple regs correctly ( outlet to inlet ) line pressure would be dictated by the reg with highest setting

THETANK

Seems like it is taken care of. It reads a little high when the engine is 1st started (first 2 - 3 minutes it is reading 7 - 8 range) once the idle kicks down it is right at 5 PSI and seems to remain there. It is a lot better than it was in the 9 -10 range, I can't believe it didn't blow off the needle and seat at that pressure.