Black88GTA

Hey all, I tried yesterday to install my Holley adjustable fuel pressure regulator, and ran into a couple problems...first, the thumbwheel was too high (when screwed in about halfway) to clear the plenum - I had to file away some of the metal on the back of the plenum to get the necessary clearance. Then the f'in thing didn't even work! Even with the wheel screwed all the way in, I got MAX 49 PSI (range is supposed to be from 35 - 65 PSI) when the pump was running, before starting the car- and then once the fuel pump stopped running, the pressure bled off to zero within 30 seconds. Accordingly, the car wouldn't stay running for more than a second or two before dying. I put the stock one back on, pressure held steady, and the car ran fine. I tried putting the Holley back on 2 more times, checking and double checking everything as I went along. Same result each time.

Now, there's no visible damage or imperfection with the Holley unit, the diaphragm is in good shape, the screws were tightened properly, there were no fuel leaks, the washers and spring were in right...i.e. everything looks fine. WTF, did I just get a bad one, with something wrong with it that I'm just not seeing? Or has anyone else have problems like this with these regulators? I did notice that the diaphragm looked a little different than the stock one - the little piece in the center that faces into the base of the regulator was smaller than stock. If that matters. I just want to know, because I like the hand adjustable option of the Holley, but I'll go with a different brand rather than exchange it if these problems are common - like if the new one does the same things.

Black88GTA

I forgot to mention that the engine in my car is the L98 350 TPI...

Brian'sIROC

I just swapped my Crane Cam AFPR for the Holley unit. I only had the plenum clearance issue like you already stated(nothing the grinder culdn't solve). You say the fuel pressure only bleeds off with the holley unit? You might want to try the stock diaphram/spring if that's feasable. Also theres a valve on your fuel pump that's supposed to prevent fuel pressure loss, the new AFPR COULD be having an adverse affect on that.