Problem with new fuel system
05-05-2011, 07:22 AM
#1
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Problem with new fuel system
Me and a buddy just finished a new fuel system on his 06 Sierra with a 370 ci t76 and 60#ers. He had 1 of 2 Walbro 255s fail so we decided to start from scratch. We used an Aeromotive 340 intank in a stock uncut returnless module with a -6 bulkhead fitting with Gates submersible hose and the old pressure port plumbed to the bottom of the module as a return. Pressure line is al -6 to a Bosch 044 inline then an aromotive filter. Then we used a firewall mounted boost referenced efi Aoremotive fpr. The intank pump runs constant via factory relay trigger wire to a Racetronix 30a relay kit with 10ga hot wire. The Bosch pump controlled via hobbs switch and another 10ga Racetronix relay kit.
The problem is intermittent and comes in two to three minute cycles. For a couple minutes the system works great with pressure around 58psi rising with tip in and jumping to 70ish under boost. The next couple minutes pressure is around 50-55 and with tip in throttle pressure will drop to nearly nothing. If you can get it into boost fast enough during the malfunction, pressure will increase to 70 as normal with the second pump.
Any suggestions?
The problem is intermittent and comes in two to three minute cycles. For a couple minutes the system works great with pressure around 58psi rising with tip in and jumping to 70ish under boost. The next couple minutes pressure is around 50-55 and with tip in throttle pressure will drop to nearly nothing. If you can get it into boost fast enough during the malfunction, pressure will increase to 70 as normal with the second pump.
Any suggestions?
05-05-2011, 10:16 AM
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Sorry, I don't know how to draw a diagram and post it. All I can do is post some pics and try to explain how I plumbed it.
Starting at the intank pump I have a 5/16 sub hose coming from the pump to a 5/16 hose barb x -6 female that screws onto a -6 male to male bulkhead fitting installed into the module lid. From there it is -6 braided hose to the Bosch inline to the filter (all-6). Right at the front of filter I cut the factory 3/8 hard pressure line and did a 37° flare with a tube nut and sleeve to adapt the hardline to the -6 male fitting on the filter. The engine side of the factory pressure line has the female quick connect with adaptor to -6. From there it is a short piece of braided hose to the side of the regulator. The other side of the regulator is also -6 braided hose adapted to the factory male quick connect ruturnless style fuel rail. The bottom port on the regulator got -6 braided hose back to where I cut the factory pressure hardline and is adapted to the hardline going back to the module lid. Under the lid on the NOW return port I put a piece of submersible hose on it that ends in the hole where the omitted factory returnless style regulator returned unneeded fuel.
Sorry for the long posts, I am bad about that. Pics coming soon. Thanks for your interest.
Starting at the intank pump I have a 5/16 sub hose coming from the pump to a 5/16 hose barb x -6 female that screws onto a -6 male to male bulkhead fitting installed into the module lid. From there it is -6 braided hose to the Bosch inline to the filter (all-6). Right at the front of filter I cut the factory 3/8 hard pressure line and did a 37° flare with a tube nut and sleeve to adapt the hardline to the -6 male fitting on the filter. The engine side of the factory pressure line has the female quick connect with adaptor to -6. From there it is a short piece of braided hose to the side of the regulator. The other side of the regulator is also -6 braided hose adapted to the factory male quick connect ruturnless style fuel rail. The bottom port on the regulator got -6 braided hose back to where I cut the factory pressure hardline and is adapted to the hardline going back to the module lid. Under the lid on the NOW return port I put a piece of submersible hose on it that ends in the hole where the omitted factory returnless style regulator returned unneeded fuel.
Sorry for the long posts, I am bad about that. Pics coming soon. Thanks for your interest.
