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Well........ I think I've finally found my fuel issues. Making a couple changes and putting the tank back in soon.
1) Check out where the previous owner had the return line going! (its the line going to the bottom of the float. It was ALL the way at the bottom. Less than 2" from the inlet for the fuel pump! Talk about heating fuel and causing fuel starvation.
2) Wired a Hobbs switch so the Holley fuel pump only has 1 pump going at anything below 4 psi. At that point the second pump will kick on. This will keep the pump from overworking and also keep fuel temps much lower.
3) Moving return to the side of the tank close to the filler neck. It seems to be the most common place and is where all the Nasty tanks return
4) Using the old return line in the tank as another vent. I will cut it as short as possible in the tank to keep it out of fuel, and then add another breather beside the stock one.
5) Holley is replacing my 12-1800 and I am trading it at my local speed shop for a 12-1600. Per Holley they no longer recommend the 12-1800 for street driving OR extended use above 90*(both of which I did a couple weeks ago). Supposedly the 1600 is much better at handling hot fuel, and is OK for extended periods of driving.
Can you repost pics of the exhaust? I 'm almost done with my truck 5.3 with a torqestorm supercharger build. I decided to ditch my dual 3" exhaust and fab up a single 4" and want to see how you did yours and your links dont work.
I using AI 1 7/8" SS LT headers with 3" collectors. Dual 3" into single 4" FM merge, 4" over the axle into a 4" hooker muffler then into a 4" dynomax ultra flow SS muffler as the driver side rear exit with a short peice of turndown at the bumper. I hope this quiets it down. Wasn't hard to fab but getting around the sumped stock tank was shitty as a regular muffler won't fit (hence the hooker as its a flat box shape). 2 mufflers are better than one lol.
I also had the same issues as you with the fuel pump and pressure issues and did the exact same thing as you. I had a clogged mess style fuel filter (40 micron by fuel rails, 100 micron before the pump) and figured out that my gas tank wasn't venting correctly for the external fuel pump (i use the holley dominator dual 1400 pump and love it). cleaned the small filter out and added a external roll over valve with filter and run a drilled gas cap and all is well.
Also did the same thing with the return line in the tank. the return line when used as a vent (was under gas with a full tank and would push fuel out with temp fluctuations outside and cause a fuel leak on the floor/ground. Cut the line and used the return and pressure line as vents that go to the roll over valve with filter.
Nice build!
Last edited by customblackbird; 02-11-2016 at 11:25 AM.