How much decay over what period of time is considered normal?

My motor was rebuilt. I changed the secondary fuel rail, added 1680's and a FPR. The rx7store kit. Primary injectors were not touched, merely removed and then reinstalled.

Once pressurized to 38psi, it takes 4 minutes and 38 seconds on average to return to 0. There are no external fuel leaks to be found.

The first test was using the stock pump. I switched it out for my Denso SupraTT pump, all the while checking to make sure that the O ring was seated correctly. It had no effect. (Off topic: Part number 13590-1270 is also the supra pump, as I could only find 13590-1020 listed?)

Am I going to have to take the primaries out again, to get them cleaned, as a most likely culprit?

 

Edit: Off topic, is part #13590-1270 also the correct fuel pump, as I could only find reference to 19530-1020?

 

It's fine. Most aftermarket FPRs are not designed to hold fuel pressure after shutdown. It's an emissions requirement for OEMs but not for performance parts.

 

Awesome. I just read the instruction manual, and it says that right on the front page. Who knew?