I really hope I could get some help over here, this is exactly what I faced.

I came to install an A&A fuel system and 95lbs injectors, other build details are unnecessary.

Scenarios:

1- Stock everything, fuel pressure hooked up to (a mechanical gauge) at the end of the rail reads a steady 58-60PSI at idle (great)

2- Stock fuel feed and rails,yet this time a regulator and return line were also added to the equation. Upon priming the pump pressure goes up to ~55 PSI (great), however as I start the car it immediately drops to ~20-30ish PSI. Adjusting the fuel regulator does absolutely NOTHING to the fuel pressure, whether fully screwed in or whether completely loose, fuel pressure is maintained at 20-30PSI

Because of this I cannot run the big pump on standby while having the small pump do the work under cruise. End up running the big pump, heating the fuel, getting annoyed with the Bosch pump's whine, and a transfer case that doesnt work (fuel is not transferring from the pass-side tank.

Then, what I did was blocked off the stock fuel feed line with a (dead-end pipe) and measured the pressure to be 58PSI, which should get the transfer system working while continously running the big pump. Just when I thought everything was okay, I discovered that under acceleration the FP fell to 40 instantly and thats when I discarded the whole idea.

Did anyone else over here EVER face an issue hooking up a fuel regulator to the stock feed line and not able to maintain nor increase/decrease pressure.

I was told on the newer vehicles the fuel system has a module and its more digital vs is being more mechanical in the past.

I mean how the hell will evap sense and work if someone is running an external pump to feed the motor. Its like trying to suck water out of a bottle that has no opening for the air to fill up instead of the water that resides there?

While I get some answers ill propose to you what I am thinking of.

PS. I hope no one suggests a bad regulator because ive been able to maintain anypressure I wish with the big pump running.

 

I'm not intimately familiar with the Corvette system, but the returnless truck system has the regulator in the bucket with the intank pump. If you just put a regulator in the system, without removing the one in the tank, then there's your problem. Even if it says "returnless", there's still a regulator in there, somewhere.

 

Well thats true as well for corvettes, there is a regulator in the tank thats job is to maintain the FP at 58PSI, however I think its somehow controlled by the ECU.

I say that because of what ive seen, how can the FP not change, nor even budge by adjusting the regulator, it will stay at 20-30 all day long, and I re-checked using a few gauges if thats what comes in mind.

I have an idea that might work, but I really want to know how are other people getting around this.

 

Since its the A&A sysyem have you talked to them? There are many people who have installed this system without any problems.

 

What year?

 

did you drain the tanks when doing your install. i had same issues with mine. when i filled the tanks full it started working fine. my guessw was and is pass tank was empty til i filled it up.