Aneroid Diaphragms.

[KiwiBacon]

My truck has had a serious gap betwen on boost and off for a few years now.
So last week I pulled the aneroid on the fuel pump apart to see if it could be adjusted to help.

I found the rubber diaphragm in there was worn to holes completely around the outside. The reason for the on-off response was it taking full boost to give the engine more fuel, with it getting virtually nothing before then.

If you've got a factory turbo engine (or an aftermarket with an aneroid) then it's easy to check.
Look for the air line that goes from the intake manifold to the fuel pump, pull it off the manifold and blow down it. If it leaks then it needs looked at.

On an inline fuel pump they're easily unbolted, so cost to fix won't be that high. Mine was $100 for the parts. Rotary pumps I'm not sure of.

[dogbreath_48]

Good advice.

A little off topic but do you have any idea what an aneroid to suit an inline pump on a 2h would be worth? I think it's the same pump as the 12h-t, would an aneroid just bolt on?

-Stu

[KiwiBacon]

Sorry mate no idea.

Your best bet might be to get the whole pump if you can find an engine that put a leg out of bed.

[dogbreath_48]

Sorry mate no idea.

Your best bet might be to get the whole pump if you can find an engine that put a leg out of bed.

Good idea but i already have a brand-spankers standard pump

[KiwiBacon]

Sorry mate no idea.

Your best bet might be to get the whole pump if you can find an engine that put a leg out of bed.

Good idea but i already have a brand-spankers standard pump

Even so, the aneroid and parts off a second hand pump can be swapped across to your brand new pump.
Of course if you have that many new parts, you will probably want a new aneroid to go with it.

My new diaphragm gives full movement at 7psi boost on a bench test. Used to take over 12psi to get any movement.