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I just swapped a 5.3l into a 98gmc. I installed an aeromotive 340 stealth pump, a-1000 pressure regulator, and 60lb/hr injectors. I prime the system and pressure will go up to 65psi but will drop quickly to 20psi and hold.
Anybody have any ideas as to what the issue might be?
Adjust the regulator?
check valve, does it matter ? no mine does the same thing when key is turned off on pressure 65 off pressure drops to 20 .. no big deal as long as you have consistent pressure during run time
I cant really adjust the regulator accurately as it will only run for 10 sec, 20 if im lucky. It will eventually drop to 0psi. Sorry I should have mentioned that
As far as I know its supposed to hold when key off. Mine is doing the same thing now. Wasn't before when I first swappedthe motor in. I changed regulator and no fix. Put new injectors but cant test yet. Others have had same issue and chances are its the hose in the tank between the pump and unit. Ill be checking that soon. I suggest u do too.
Yes it will run fine as is but at WOT at high rpm, motor will bog. If ur under boost, ull kill the motor. just cuz it runs doesn't mean its ok.
I installed a brand new sae 30r10 hose. as the one that came with the pump wasnt long enough. For a $27 hose (after my discount at napa) it better not be messed up.
That's what I thought. I used the clamps that came with the kit. Not saying thats ur problem as idk if thats thats mine either. Just saying its a possibility since others have stated thesame thing. Ill ber checking mine soon. If the easy checks ain't work out, just saying u might wanna look into it
Pinch the return line; now does it hold?
If not, pull the tank.
Now i wish i didnt go with stainless braided lines haha. Other wise piching would be easy. ill try it tomorrow.
Sometimes i wish i lved in the USA just so i could get better deals on parts.
Its the hose in the tank 90 percent of the time
Mine was losing pressure key off to mine ended up being the regulator I am using a stock one.
There was a slow leak at the bottom of the fuel pump hose. I threw on a smaller gear clamp and its holding pressure now. Thanks for all the help everyone
damit. that means ill be dropping my tank too. lol glad you got it fixed. screw those plastic clamps!!!
I just pop the box off rather than dropping the tank. 8 bolts and a couple wires and a few extra hands lol.
Still drops pressure but extremely slow, stops around 20psi though. I have both clamps as tight as they will go so i dunno where the pressure drop is coming from. I'm gonna cut a small door in the box just in-case i run into more issues with the fuel pump.