Fuel Pressure Regulator problems..

[suprafanatic]

Iv been having problems with my fuel pressure regulator. its an adjustable aeromotive FPR and the fuel pressure is constantly changing every time i drive the car. One day i'll set it at about 32, then the next day I go drive the car the pressure will read like 40, or some times in the 20s. I just cant figure out why it wont stay at the pressure that I set it to be at. Also do you set the pressure with the vac. line off or on? I'v also noticed when the car is first started and cold there is no vaccum in the vac. line to the FPR. Once the car is at operating temps there will be vac. in the line. Any Ideas?

 

[Piratetip]

Set base fuel pressure with the vac line off.
I suggest you look into why there is no vacuum to the FPR when cold.

 

[grimreaper]

if the gauge is liquid filled, the heat will change the reading. There should be a vent port on it.

Is the fuel pressure VSV hooked up still?

 

[suprafanatic]

The gauge is liquid filled, i'll look and see if there is a vent port on it. Also im not sure what the fuel pressure VSV is??

 

[grimreaper]

You might have to loosen the gauge and spin it around if need be.

Its under the intake mani In front of the egr vsv. When coolant temps are high enough it allows the regulator to be opened to atmosphere to avoid or help vapor lock on start up. If it is hooked up, maybe its opening constantly.

Where does the regulator get vac from?

 

[suprafanatic]

I did not see any vent port on the gauge.. There were a couple screws in the back of it and then a rubber circle on the side of the gauge..
I believe i used the vac. source that the stock fpr used. Its at the front of the intake mani. There are two seperate metal tubes, im using the bottom one for vac.
Today I started the car and set the Fuel pressure, I then turned the car off and back on and the pressure went up even higher.

 

[grimreaper]

that rubber circle is the port, it will bleed the fluid out if you have it facing down or sideways. Pull it off completly, its just a little plug, when reading the gauge

 

[suprafanatic]

well its facing kinda down at an angle... so should it be facing upwards? And when you say take it out, do you mean take it out for good? or just take it out while im adjusting or reading the pressure?

 

[grimreaper]

I had to turn my gauge so that it faced up so i could vent it (makes for an odd reading angle). Only while reading or adjusting.

A non filled gauge might make things easier in the long run.