LQ9 Drop in Fuel Pressure at WOT
#1
LQ9 Drop in Fuel Pressure at WOT
Hey everyone
Heads and cam lq9. Full bolt ons. Walbro 255, marine injectors. Stock intake and TB 1999 truck - return style fuel
I just installed - 1 month ago. Runs 55psi no vaccumm at Idle. Sees 42-44psi at WOT. Wideband is reading lean condition. FP reading off shrader valve on Passenger side fuel rail.
What could cause this? Possible bad pump?
thanks for the help
Heads and cam lq9. Full bolt ons. Walbro 255, marine injectors. Stock intake and TB 1999 truck - return style fuel
I just installed - 1 month ago. Runs 55psi no vaccumm at Idle. Sees 42-44psi at WOT. Wideband is reading lean condition. FP reading off shrader valve on Passenger side fuel rail.
What could cause this? Possible bad pump?
thanks for the help
#4
11 Second Hall Moniter
iTrader: (22)
Hey everyone
Heads and cam lq9. Full bolt ons. Walbro 255, marine injectors. Stock intake and TB 1999 truck - return style fuel
I just installed - 1 month ago. Runs 55psi no vaccumm at Idle. Sees 42-44psi at WOT. Wideband is reading lean condition. FP reading off shrader valve on Passenger side fuel rail.
What could cause this? Possible bad pump?
thanks for the help
Heads and cam lq9. Full bolt ons. Walbro 255, marine injectors. Stock intake and TB 1999 truck - return style fuel
I just installed - 1 month ago. Runs 55psi no vaccumm at Idle. Sees 42-44psi at WOT. Wideband is reading lean condition. FP reading off shrader valve on Passenger side fuel rail.
What could cause this? Possible bad pump?
thanks for the help
#6
TECH Senior Member
iTrader: (27)
Has your electrical bulkhead been upgraded to the new style? The older ones that would have come with your 99 are only good to flow around 14 amps. Also, I would definitely upgrading the wiring harness to the hotwire kit from Racetronix. Finally, your low FP could be caused by multiple things, including a clogged fuel filter or leaking fuel hose. I'd recommend using Nylon tubing inside the tank. It's superior to rubber hose and cheaper too.
#7
Thanks for the input gmctrk.
I have an email into racetronix to get the link for the hotwire kit i need. Gonna order that. Gonna slap another gss340 in while i have the tank down(only 75$ my cost).
Ordered another Hose for new pump
Got a new fuel filter to go on too. Last time fuel filter was replaced was 2 years ago, truck has seen maybe 1000 miles since then.
Just gonna swap it all out, for piece of mind, and test it all after. If i new there was such issues with the wiring on stock fuel pumps I would have upgraded before.
O well live and learn
I have an email into racetronix to get the link for the hotwire kit i need. Gonna order that. Gonna slap another gss340 in while i have the tank down(only 75$ my cost).
Ordered another Hose for new pump
Got a new fuel filter to go on too. Last time fuel filter was replaced was 2 years ago, truck has seen maybe 1000 miles since then.
Just gonna swap it all out, for piece of mind, and test it all after. If i new there was such issues with the wiring on stock fuel pumps I would have upgraded before.
O well live and learn
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