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?
Back Alley Motorsports 98 GMC
-5.3l LM7 bored to 5.7l Thompson Motorsports -72mm T4 Magnum Turbo
-TU1 Custom Grind cam(spec speed.inc) -799 heads
-.660" Trick Flow dual valve springs -Forged Probe Pistons 3.902" flat top
Adjust the regulator?
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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
Simple: 408 on steroids!
single digits coming soon!
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
Last edited by shmiet; 07-27-2013 at 09:30 PM.
Back Alley Motorsports 98 GMC
-5.3l LM7 bored to 5.7l Thompson Motorsports -72mm T4 Magnum Turbo
-TU1 Custom Grind cam(spec speed.inc) -799 heads
-.660" Trick Flow dual valve springs -Forged Probe Pistons 3.902" flat top
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.
Like Tumbler in "Gone in 60" I'll drive anything with wheels or without
My 95 ECSB LQ9 build thread - http://www.ls1truck.com/forums/lsx-t...to-95-obs.html
CALI LEGAL ENGINE SWAP!
Stock 03 LQ9, DBW, 95' 4l80e w/ Transgo shift kit, 2010 50# GM injectors, 2800 Circle D stall, Spectre CAI, Upgraded trans cooler, Home-made E-fans/shroud, Dual EP-381 fuel pumps w/Home-made hotwire kit
NEXT ON LIST: Dual Battery setup, CAM/Valvetrain upgrade, Build my own rear mount turbo, TRU-TRAC, HIT THE STRIP!!!
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.
Back Alley Motorsports 98 GMC
-5.3l LM7 bored to 5.7l Thompson Motorsports -72mm T4 Magnum Turbo
-TU1 Custom Grind cam(spec speed.inc) -799 heads
-.660" Trick Flow dual valve springs -Forged Probe Pistons 3.902" flat top
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
Back Alley Motorsports 98 GMC
-5.3l LM7 bored to 5.7l Thompson Motorsports -72mm T4 Magnum Turbo
-TU1 Custom Grind cam(spec speed.inc) -799 heads
-.660" Trick Flow dual valve springs -Forged Probe Pistons 3.902" flat top
damit. that means ill be dropping my tank too. lol glad you got it fixed. screw those plastic clamps!!!
Like Tumbler in "Gone in 60" I'll drive anything with wheels or without
My 95 ECSB LQ9 build thread - http://www.ls1truck.com/forums/lsx-t...to-95-obs.html
CALI LEGAL ENGINE SWAP!
Stock 03 LQ9, DBW, 95' 4l80e w/ Transgo shift kit, 2010 50# GM injectors, 2800 Circle D stall, Spectre CAI, Upgraded trans cooler, Home-made E-fans/shroud, Dual EP-381 fuel pumps w/Home-made hotwire kit
NEXT ON LIST: Dual Battery setup, CAM/Valvetrain upgrade, Build my own rear mount turbo, TRU-TRAC, HIT THE STRIP!!!
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