Quote:
Originally Posted by DirtyLarry
Here is my ’72 C20 with a TBI 350 sending unit with a factory return line. With the low fuel pressure TBI runs I haven’t had any issues running the return fuel through the little 5/16 line.
However, I wouldn’t recommend the little 5/16 return line on a higher pressure TPI system that runs in the 40 psi range or the later LS engines run up as high as 62 psi. The 8.1L in my ’78 K10 did not like the small 5/16 return line through the original fuel tank switch valve as it was way too restrictive causing the fuel pressure to run extremely high….like a 100 psi at idle! I ended up having to completely redesign the fuel system on that truck to create a larger return line and still have dual fuel tanks.
Again, this will work for low pressure TBI but not for higher pressure multiport.
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Thanks for the pic. I might have ordered the '72 sender had I not seen the size of the return. Pretty sure that won't work with TPI. It'll just be easier to make my own return out of a '67 unit. I don't have much trouble with the pump I have now being too loud. I can't tell who makes it because it's covered in silicone rubber. Maybe that's an option for some of you. The little bit I have driven the truck, it seemed like it was starving for fuel, but that could be a timing problem. It's backfiring in the intake right now, which I'm guessing is a timing issue, or a stuck intake valve. Not really on the same subject of this thread, just kinda where I'm at with the PU right now.
