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Hey thanks for the reply I read through your thread. Why did you stay returnless? My truck is an 09 flex so same sending unit you used. I may send you a pm or 2 for help when I start moding the unit.
I stayed returnless because no one else does lol! I think there are a lot of advantages to having a returnless system WITH PWM. Less lines, clutter, use smaller GM injectors, etc. I figure, GM went that route for a reason and use it on everything from a Cruz up to the ZR1. For someone who already has a flex fuel truck and a FSCM that is supported in HPTuners, it is a lot cheaper too. 100.00 for the pump kit and 48.00 for the license to program the FSCM.
Most newer aftermarket pumps have internal check valves, so you shouldnt have to worry about loosing prime that easily (the walbro 400s and 450 do anyway).
Do not cut the outer bucket, leave it intact. You can drive below half a tank, just dont go ape **** doing hard accelerations. Generally if you leave the bucket intact and have the return (yes even returnless systems have a "return") going inside the bucket you should be ok to 1/4 tank or so.
You are correct. The reason I mentioned the check valve is because Smokeshows write up has a "T" in the pressure line to go to the Venturi and believe he had an issue with pressure drain. This would work "if" the line had a check valve.
Its mainly due to emissions. Returnless systems do not have fuel circulating through the hot engine bay and back to the tank so there are not as many fumes and vapors to deal with. The typical drawback is not having a reference to raise pressure with boost, but the FPCM can solve this somewhat by ramping up voltage.
started taking my sending unit apart but does not look like others I have seen. Need some help identifying parts I need and don't need.
The pump itself has some plastic stuff attached to the bottom of it wondering if I need to keep it. What is the metal can that the pump sits inside of? The pump fills it up then it exits out to the fuel line. Is it just part of the factory regulator setup? Is it the filter?
Last edited by crashmymax; 05-30-2017 at 10:19 AM.
That is definitely one of the aftermarket sending units I tried to stay clear of in my endeavor. What fills the bucket? Any better pics of the bottom of the white bucket? That white plastic piece on the bottom of the pump is definitely a Venturi of some sort. Better pics of said plastic thingy and what was connected to it? Seems like the Venturi fills the can but trying to understand how the bucket gets filled.
That is definitely one of the aftermarket sending units I tried to stay clear of in my endeavor. What fills the bucket? Any better pics of the bottom of the white bucket? That white plastic piece on the bottom of the pump is definitely a Venturi of some sort. Better pics of said plastic thingy and what was connected to it? Seems like the Venturi fills the can but trying to understand how the bucket gets filled.
Pretty sure its a factory unit. They pulled it right out of a truck at the salvage yard. It also has a made in mexico sticker on it. I will post more pics tomorrow. Thanks.
05-28-2017, 12:21 PM
