4AGE Fuel pressure regulators.

[Devils]

Hi,

This may be a strange question to the people in the know... so I hope I can get an easy answer.

I am not getting any fuel through the return line.
I have taken the fuel pressure reg off and put a vac source on the diaphragm, it will not open. I have put a pressure source on both sides of the fuel passage and it will not open.

This is where it gets really strange...
I have two other fuel pressure regs off other 4AGE motors. These other two have hose tails rather than a banjo fitting, one is the same size as the orginial mentioned above and the other has a larger diaphragm. Both of these also do not open.

What am I missing? Surely it cannot be possible to have 3 stuffed regulators.

The reason I noticed there wasn't any fuel comming from the return line is because the feed line seems to be over pressureizing and causing a hose fitting to leak. I could not find my pressure gauge to see what it is running at but seems strange that no fuel AT ALL is coming through the return line.

Cheers,
Craig.

[SHEPPO3930]

Fuel regs are usually set to bleed off at 45psi +/- manifold pressure. So u will need to put more than 45psi into the reg to try and open it. Maybe try a combination of both pressure in, and vac on the diaphragm? For what a new aftermarket reg costs, I'd simply replace it.

[jondee86]

This is a pic of a typical 4AGE 16V fuel rail...



On the RHS is the pulsation damper which threads into the rail, and holds a banjo fitting under the hex section. On the LHS is the fuel pressure regulator that fits to the rail with a plain stub and o-ring, and is held in place by two bolts.

The pulsation damper has a spring-loaded diaphragm inside the mushroom head, and reduces the effect of the pulsations produced by the injectors opening and closing.

The FPR is a pressure sustaining valve, which allows fuel to flow thru the valve from inlet to outlet once the pressure differential across the valve exceeds approx 43psi. It is vacuum compensated, so that the valve opens at a lower pressure when manifold vacuum is high. Vacuum alone cannot open the valve when it is off the rail. As suggested above, you would need pressure on the inlet as well as vacuum on the compensation hose.

Question: When you found that you had no fuel in the return line, was there fuel in the rail, or was it dry ??

Cheers... jondee86