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Old 10-13-2007, 01:17 PM
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Join Date: Mar 2005
Location: Santa Cruz, ca
Cobra Make, Engine: Shelby CSX4788 with a Dawkins performance 490 ci iron genesis block hydrualic roller
Posts: 246
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Default Fuel system issues

Okay - just in case any one is wondering, I realize I am an idiot. With that out of the way, I can get to my dilema.

I tried to fire up my cobra for the first time to try and diagnose a clutch issue. The mechanical gauge was only reading ~ 1 psi at the end of the fuel log. I substituted the mechanical gauge on the end of a #4 braided line from one of my race cars. I was getting 1 psi on that gauge also. I measured it at the fuel filter and it was 1-1.5 psi. It the out flow from the two pumps in the trunk it is 7-7.5 psi. Is that enough pressure at the pumps? Oh yeah, and the fuel pumps don't always come on or stay on if they are moved up or down . The wiring doesn't care and each pump seems to be running when they are running.

Now for the idiocy:
when I originally plumbed into the fuel lines that were on the car from SAI, I saw that there were 2 cloth covered lines. I assumed that they were both feed lines. Looking at the bottom of the fuel cell now, I see that they both come out of relatively the same place, but one goes up to the fuel pumps and the other one just heads towards the engine compartment as a .................. return line - doooh .
-Is this the way the fuel cell is supposed to be plumbed?
-Do I need a return line for a 427 fe?
-Can I somehow some how run the both of the two -6 lines from the fuel cell to the pumps instead of using one as a return line since pumps push better than they suck?
-Any suggestion on plumbing the return line into the system if I do need it? (I am using a -8 aeroquip fuel log with the -4 fitting on the end to supply the remote fuel pressure transducer).
-Can I eliminate the fuel pressure regulator that I have plumbed before the fuel filter since I am only getting 7 psi at the pumps in the trunk?
-Is a single -6 line big enough to feed a 427 fe?
-Has anyone else has problems with their fuel pump and what did they replace them with?
I am tempted to plumb it like I did the race car I borrowed the fuel pressure gauge from -> -10 braided from the fuel cell to a holley fuel pump, - 8 braided to the fuel pressure regulator and filter, - 8 to the fuel log / carb.

Thoughts, help, insights all greatly appreciated. Thanks
John(;-)
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