I did a Walbro 255 pump install along with an Accel AFPR and new fuel filter not too long ago. The car runs fine and the pressure adjusts fine as well, but I notice when I shut down the engine, it loses all fuel pressure almost instantly. Is this a potential problem here? I drive the car everyday and rely on it for transportation so I can't afford to be burning up parts. It starts fine, just lacks fuel pressure in the lines after shut off...

 

An AFPR is not a worthwhile mod for the vast majority of cars and will screw up Ion's tuneing. Should be easy enough to swap back to stock and if it holds pressure then, then you know it was the AFPR, if the pressure still drops then it at the pump end.

 

I helped a friend install a Walbro 255 lph last year. About 3 months later his didn't hold pressure either. Turned out the check valve (internal to the pump) failed. We ended up replacing the fuel pump, that cured the issue. I also have a Walbro and it works just fine.

 

I tend to think it's the AFPR, but I put them in at the same time as the pump so it's kinda hard to tell. My other Camaro has a walbro in it too and it's fine. It runs fine, I'd leave it alone if I knew it wouldn't cause problems...that's what I'm trying to figure out.

 

Depending on what lines you have, you could crimp the supply line as someone else turns off the engine. I use a pair of needle nose vise grips with pieces of rubber fuel line on the jaws. If the pressure still drops, it has to be either the injectors or fpr as you eliminated the fuel pump as the problem. Unless you have a leak that you can't see at the rail.