Begi AFPR Help
 

I installed a Begi afpr along with 305cc injectors. It idles amazingly smooth and at the correct AFR without any adjustments. It's the 2025 I believe, made for Aftermarket FI systems.

I've got it hooked up with a restrictor in the signal line, and 2 check valves on the bleed as per Ben's thread. The problem I'm having is that when the signal line is hooked up, the fuel pressure drops from 48-50 psi (I set that with the center bolt) to about 36 psi. When I rev the engine the pressure does climb back up as it approaches atmospheric pressure. Also the fuel pressure needle oscillates like crazy. Is there something wrong with the fuel pressure being so low? I just wanna be sure everything seems ok before I drive it.

Did you check the pressure your fuel pump is able to put out? If your factory fuel pump is dying or weak it might produce those kinds of results?

Woops, signature corrected. I've got the 190 hp.

it almost sounds like you hooked up the fmu on the fuel feed line. 36psi at idle is what the stock regulator should run. but what ever you adjust the fmu at, it shouldnt drop lower than that.

I'm positive it's on the correct side of the fpr as I'm using the same lines I had hooked up to the vortech fmu.

hmm, well either turn the screw in some more, and test again. or just take it for a drive and see if it is actually riseing.

Well, wow, it seems that your FMU works exactly like it's supposed to.

Let me see if I can clarify this for you. The BEGI 2025 FMU, only effects fuel pressure, from ambient pressure up. When you set the base pressure of 48-50 PSI, you where setting the pressure the FMU will hold once the manifold pressure reaches ZERRO; this is why you set it with the trigger hose removed. Below this, under vacuum, you are operating off the OEM regulator around 35 PSI. As you start to climb out of vacuum, the rising rate regulator will start to take over from the OEM regulator, clamping down on the return side, which in turn will increase the fuel pressure on the fuel rail. AS your manifold pressure crosses over from vacuum to boost, you should once again see the pressure reach 45-50 PSI. once into boost, the fuel pressure should rise proportionally.
As far as fuel pressure bouncing, I would consider this normal, as long as your AFR is good, fuel pressure is of little relevance.

that's how it should work. you just set the preload. with the signal line back, only the oem fpr is doing anything, thus 36psi.

Give Corky a call. We are here for another few hours. I am sorry, but I am no help with the FMU stuff.
Stephanie
830.438.2890

Ahhhh ok! I was under the impression the base pressure for the Stock Fpr should be at 43.5psi. It's all working properly then. I went out for a drive today and the AFRs look pretty good. 12.5 and then richening out 10 and just barely dipping into the 9s right at redline. I didn't even have to make any adjustments to the needle valve.

raise the pre-load and lower that top-end AFR with the needle. its more damaging than benefiting once you go that rich.

way too rich

Alright, will do that. Thanks guys!