Faisalm

So I'll write the detailed story here and a TLTR at the end for those who don't want to read.

I purchased a Full Blown dual pump a year ago, tried it, had some issues with it, went with the BR double fuel pump. Along with the double fuel pump I installed an HKS fuel regulator and an HKS fuel rail.

About a week ago the car was running just fine, AFR's at WOT we're very safe, everything was perfect and the car was running beautifully, except for a few high rpm phantom knocks which I still can't find the source of.

Yesterday, I noticed extreme knocking and lean AFRs (12.1-12.2 at high rpms, car is on pump gas), and noticed that my idle fuel pressure has dropped from around 38psi to 31-32 psi. I did a boost leak test to check if my secondary pump is activating under boost, but I couldn't hear any noise from the fuel pump, so I thought that this was the issue. I replaced the secondary pump with the Full Blown fuel pump and gave it another go. Still, the issue was present. Low fuel pressure and lean AFRs.

So I decide to work on the car the next morning. When I try to start the car the next morning, the primary fuel pump decides to fail. I try a couple of things to get it started with no luck. I swap the Walbro with another Full blown fuel pump so now I have 2 Full Blown fuel pumps attached to my BR double pumper housing. The car starts up immediately. I check the fuel pressure, and it's still low. I check the fuel lines, the fuel rail, the fuel regulator, everything is just fine.

I can still change fuel pressure with the fuel regulator, so that is working just fine, but that still doesn't solve anything since the fuel pressure should return to normal without me modifying the fuel regulator, correct?

My mechanic says the electrical connections are fine as well, so that can't be it.

FYI, the Walbros that came with the BR double pumper have only been used for 200 miles max.

I took the car out for a test on the Full blown fuel pumps and it was very rich at WOT (10.2 - 10.3 at high rpm), but still knocking.

Now I'm very confused and don't know what to look for. Any suggestions?

TLTR: Both Walbros from the BR double pumper kit gave up (not at once). Car has lower fuel pressure at idle and WOT. Replaced Walbros with Full Blown fuel pumps, issue is still present. Lines, electrical connections, fuel regulator have all been checked. WOT with Full blown pumps cause richer WOT AFRs but still low pressure at idle.

6466evo

am having the same issue...did u manage to solve ur issue...my fuel gauge is dropping pressure under boost n car is going lean.....

Faisalm

I solved my issues, yes, but I took it one step at a time disconnecting the fuel lines where ever possible and turning on the pumps to see how the flow is.

For me, it was just a case of extreme bad luck. The fuel pumps just weren't pushing enough fuel and they were malfunctioned. I just purchased another set of fuel pumps and all went well.

Are you on a Hobbs switch?