Just a quick question, when i turn the ignition on (car not started, but fuel pump primed) should I be holding a fair amount of fuel pressure on my gauge? When I prime the pump it jumps up to about 30 ish then goes back down to 20 then slowly sinks. Wanted to make sure this is normal before I take the car off the stands and try to start it.

Thanks

 

I've had two fuel pressure regulators.

The first, a Mallory, wouldn't hold pressure at all with the car off. I drove the car like this for a very long time with no real issues.

Now, I believe I have an Aeromotive and it will hold pressure after the car is shut off.

I would check to make sure you don't have any leaks, and if you don't I wouldn't worry about it too much. The only thing is that you'll have to remember to prime it before cranking it.

 

It shouldn't drop like that., maybe a slow drop if any.

 

it will hold pressure and slowly drop. it should reach full pressure almost when you prime it though, 30 is too low...

 

how slowly should it drop, i adjusted the **** a little and it hits about 45 psi, but it sinks pretty quickly, like down to almost zero in 30 seconds

 

What kind of FPR is it? Like I said, I had one that did that and I had no fuel problems or any other issues with it for a long time. One shop thought that my check valve in the tank was bad, but after I replaced the regulator (for another issue) it held pressure for quite a while after being shut off.

 

It's going to return slowly to the tank, so it is normal to see a pressure drop when the key is on, and engine off. If your swirl jet is over drilled or under drilled, it might drop a little faster or slower. As long as its operating normally at idle, and under boost, it's fine.

 

What FPR and pump(s) are you using? On an aeromotive w/ triple walbros it holds pressure for a few minutes. With a weldon 2035 and aerom fpr, pressure drops instantly.

Run your hand around the fittings to check for leaks, and use your nose

As long as you are leak free and it maintains pressure when triggered on I don't see a problem.

 

ok i turned it on and it was stable at idle, everything is A-OK thanks for the help guys.

i do have the swirl jet drilled out to .078 so that may be why its dropping fairly quickly when i prime it