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Discussion Starter #1
Hey guys, what's the easiest way to check my LS3 fuel system for leaks (before I put the body back on) - setting up the system with in-tank pump (Tank's Inc GPA pump), the corvette LS filter/regulator, Holley Fuel rails with pressure gauge on the inlet to the rail. Without attaching any electronics will the injectors be "closed" and hold pressure ? My main concern is the filter/regulator connections ... it currently has the "quick disconnect" fittings and they make me nervous (outlet seems much too loose) but before I buy the regulator with the AN fittings I'd like to confirm if I have an issue or not.
 

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Hey 77blue, I just finished doing that very thing! With the body off, I put my fuel pressure tester gauge on the hard line just before it attached to the fuel rail. I then energized the fuel pump with a 12v battery and checked for leaks and proper pressure. I used the LS filter/regulator and a Delphi FG0053-04 pump, I would guess the pinouts are likely the same but better check to be sure. The pinouts for the Delphi are as follows:
A = Sender return
B = Pump +12v
C = Sender out
D = Gnd

And yes, I had 2 small leaks on the AN joints. I attached a picture but it's kind of hard to see much of anything other than wires hanging out of the pump. The pressure gage is up near the motor. It turns out the stainless fuel tubing I used to make all the fuel lines had a seam on the inside that affected the 37° flare. I had to burnish the inside of the flare to eliminate the leaks. Not a big deal to do, but if I had it to do over I would have bought a higher quality stainless tubing. I tried to take a picture of the seam problem but it didn't come out. Be glad to provide details if anyone is interested. I plan to test the integrity of the fuel rails/injectors separately. I would already have that done but am going to have to remake the line that connects to the fuel rail. I forgot how big the brake booster is and the line I made hits. Also had to cut clearances on the coil cover. I also spun the LS3 over with the starter (plugs out) to ensure oil pressure since it has been 2 years since it was started. I temporarily connected a pressure gauge to the tap just above the oil filter. I ran the starter for 10 second bursts and waited a couple minutes between bursts to let the starter cool. Started getting worried as I was seeing no pressure. I've seen oil pumps that won't self prime if dry, so I removed the OEM oil pressure sensor on the back of the motor and squirted oil into the hole. It connects directly to the main oil gallery on the left side of the motor. I was surprised that it took almost 12 oz of oil until the gallery was full. I put the OEM oil pressure sensor back in and got pressure almost instantly the next time I tried. So if yours has been sitting awhile you might want to go ahead and prime it like that right off the bat. Sure a lot easier to fix things with the body off!
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One thing I left out about the pressure tester. If you look closely at the second picture you can just make out where the tester is connected to the AN-6 fitting. The vent line from the tester goes into the yellow coffee can on the floor. There is a button on the tester that you push to vent the system. So with the pump running I could push the button and purge the line of trapped air and any possible contaminants. Then when the button is released the system is sealed off and you can read the regulated pressure.
 

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Discussion Starter #4
Thanks zimmej51, the idea of a gauge with the purge valve makes sense. I didn't want to be pushing fuel to the injectors at this point when I'm only trying to check for leakage.
 
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