Ok , so I just installed a Holley afpr and I had trouble setting fuel pressure. It will only set to 30 psi before the adjuster **** would bottom out. What I did was remove the plenum again, took out the adjustment knod and I inserted a small solid round piece of metal that measured about 7mm wide and about 4mm tall right between the regulator housing and adjuster **** (Kind of an extension If you will). I was able to then set my desire fuel pressure @ 48psi and yes with vacuum lines capped off. I dont have any fuel leaks and the car runs great. Did I get a defected item? Is the diaphragm going to tare sooner than later?

 

I have that same AFPR and had no issues with install or setting pressure. Did you cap/block the FPR vac line or leave it hanging while adjusting the fuel pressure? Regardless of that you shouldn't have to add anything to make it work, I would call Holley and see what they say.

 

I'm a bit suspicious of that as well, you should be able to get much more than 30psi before it bottoms out. I felt like I had to screw mine in pretty far, but didn't bottom out and I'm getting 47+ psi. Maybe your diaphragm is in backwards?

 

this is the picture diagram, exactly how I install it.

 

everything was installed correctly, I double checked when I had to take the plenum off again.

 

Yes, vac line were capped

 

When setting the AFPR you disconnect and leave the line hanging, creating a vacuum leak, while adjusting to simulate WOT and then set to whatever pressure you want. If you adjust with the line capped or blocked or still connected to the vacuum port your pressure will be too high.

 

Oooooh, that explains it. Thanks.

 

No problem, glad that I could help. The AFPR is a nice mod, I currently have mine at 47 psi and car runs good.

 

So its been a week since I installed Holley afpr. Today i decided to check fuel pressure just for the heck of it, and found that the engine idle does not change when I disconnect the afpr vacuum line . Also fuel pressure is the same (47psi w/car on) with vacuum on or off. I'm not sure if this is normal, but the car runs great though.

 

Hmm that is odd, fuel pressure should drop a good amount when you reconnect vacuum at FPR and go up when the line is disconnected.