erratic fuel pressure

[bholker]

I've got an issue with erratic fuel pressure. I've got a walbro 340, adjustable pressure reg, electric gage.
at idle I can set it with vac line off at 42 psi, then off and on with the line a few times and I can get it to read anywhere from 38 to 48 psi. When I'm driving around I've seen it go down to 10 psi at crusing.

At WOT it always seems to get up where it should be 58 psi or so at 16 psi boost.

I'm leaning toward fuel pressure regulator just not doing the job its supposed to.

Does the 340 have a sock on the input. I can't remember. I was going to drop the tank and check that out, becuase have have been running e85. I replaced the fuel filter with really no change.

Thoughts?

 

[1WH1]

fuel pressure

your story sounds just like mine two days ago
pressure was all over the place, and scary low
I put a mechanical gauge on to check while driving,
and pressure was just where it should be at idle & boost
I cleaned the connection for the elec wire & where the
pressure switch screws on the fuel rail - and all was well again
my elec gauge is a cyberdyne - I'll add this cleaning to my
routine maintance, until I get a mechanical gauge
I hope it's that easy for you.

 

[bholker]

Mine's a cyberdyne electric gage too. I think I still have my mechanical gage around. I'll have to swap it in and find out.
So you cleaned both the terminal at the pressure transducer (electrical connection) and cleaned up inside the transducer before reinstalling it on the fuel rail?
I suspected that too, but have not had it installed that long.??