'75 1.8l with stock L-jet.

1) Should fuel be able to flow through the pressure regulator without manifold vacuum applied to the vacuum port? I'm priming/testing the fuel system before burying it in all of the air intake stuff. With the fuel pump on, no fuel is coming through the regulator.

2) With the regulator blocked, should the lines and fittings be able take the full pressure of the pump without leaking? I'm using a stock pump, but I have no idea what the pressure goes up to without a functioning regulator.

Thanks,

Mike

The L-Jet fuel pressure regulator does not shut off the fuel flow. It just provides a restriction to keep the pressure at about 28-32 psi. The vacuum port is attached to the manifold, and it will make the fuel pressure go up when there is no engine vacuum, like when you are accelerating hard.


If your pressure regulator is leaking fuel out of the vacuum line port, or it doesn't let fuel go out the return line at all, then you have a bad regulator.

There is no adjustment on them.


Hope that helps.

Clay

a stock pump, the old three port pump will relieve pressure itself.
they have a pressure relief valve that blows (its like a pin valve backed by a spring).
it returns fuel directly to the return line to the tank.
it should fully blow at 70 lbs max.
thats what the pressure would go up to if the regulator was blocked.
and then it fully opens and sends the fuel back to the tank.
if that helps.
and any modern pump which is a two port does the same thing, but backwards through the inlet port.
the fuel lines and connectors if in good condition can take that pressure.
(that pressure would only build in the line between the pump and the regulator, i think, before blowing back through the pump relief valve).

the fuel can flow through the regulator without the vacuum line being hooked up to the port. it will be at a higher pressure - approx 35/36 ibs. thats the standard test.
vacuum hose unplugged, ignition on, flap inside air flow meter pushed open. if its not 35/36 its not good.

at idle, with the hose in the port it should be around 28 lbs.