Installed fuel pressure gauge...what should it read?

[91LX_5L]

I installed a rail mount fuel pressure gauge. It reads 32 when motor is running. Is that normal? What else should I look/test for, once its warmed up? with just igniton on etc? what are some numbers that are good so I know if somthing is wrong.

 

[CManT1914]

It should read right around 30 at idle, and 39-40 under throttle or with the vacuum taken off the fuel pressure regulator.

 

[91LX_5L]

which vaccume is this? I dont have an aftermarket regulator. can you explain so i can find it, will it squirt out fuel? do i test at idle.

thanks man

 

[CManT1914]

which vaccume is this? I dont have an aftermarket regulator. can you explain so i can find it, will it squirt out fuel? do i test at idle.

thanks man

Honestly, if you're reading 30 or so at idle, and 39-40 when you hit the throttle, you're good to go.

But.... the vacuum line runs from the fuel pressure regulator to the intake manifold, on a vacuum tree on the elbow. It's small, and easier to take off the elbow than the actual fuel pressure regulator (for me anyway). If you take that vacuum line off, it's like you're under throttle, and so the fuel pressure goes up.

You'll need to remove that vacuum line if you ever get an adjustable fuel pressure regulator, and you try to set the fuel pressure.

 

[91LX_5L]

ok the 39-40ish when on throttle is that like 1/2 throttle at what like 4,000rpm?

thanks

 

[CManT1914]

ok the 39-40ish when on throttle is that like 1/2 throttle at what like 4,000rpm?

thanks

Pretty much at any rpm. Now 1/3 throttle you should only see 34 or 35 or so. 2/3 throttle it should be up there. It's not really a set number for a set rpm and set throttle. As long as it climbs when you give it more throttle, then you're okay.

 

[91LX_5L]

thank you

 

[CManT1914]

thank you

Anytime.