So I have an Aeromotive regulator, Supra fuel pump, KGparts secondary rail with 1680s and primary with 850s. When I turn the ignition on, not starting the car, just on, the pressure goes up to 38 and fairly quickly drops to 30, roughly 30 seconds, and takes about 3 minutes to get to 24, then it takes a good hour to drop to 10. Is this normal or indicative of a leak?

With the KG fuel rail I can't do an injector leak test since I can't figure out a way to secure the injectors in the rail with it not attached. Inspected o-rings, one didn't look good so I replaced it and decided to just replace the others too. No change in the above drop. No exterior leaks that I can find.

So before I do any more work I want to make sure there's an issue and I am not wasting my time.

 

That's normal, what you want to do is keep the key at on, jump the fuel pump to set fuel pressure and check leaks.

 

Aeromotive does not engineer their regulators with the intention of holding pressure after the pump is off. While occasionally I run into one that seems to, it is not typical of them. Generally most of the pressure will have bled off within a few hours.

Its been several years since I had a conversation with them about it... but *if* I recall correctly, adding the feature would come at sacrifice of pressure stability or consistency, one or the other.

 

Its normal for the fuel pressure to leak down gradually. You can jump the fuel pump (fp to gnd) pins in the diagnostic box, pull the upper intake manifold, and look for signs of injectors leaking but I don't think you have a problem. Does the car run ok?

 

Installed a reman and had the car idling going through the apexi learning process. About 30 minutes in and the exhaust started sounding like an army helicopter and idling rough. Tested again and same thing happens after it warms up. Will check spark next, hope it's not the motor...

Any ideas?