Out Banjo persistant leak

[bbob203]

Td your troubleshooting techniques amaze me more and more every time.

[TylerDurden]

I'm just happy to have found a use for the vinyl tubing that I'll never use for fuel lines.


As for the pressure at the bolt threads, a bit of poking around the webz reveals there are NPT threads, BPT threads, Metric Pipe Threads and the Germans have a unique thread also.

http://www.engineeringtoolbox.com/thread-standards-d_776.html



It is my impression that the threads seal most of the IP internal pressure from the banjo fitting.

[sgnimj96]

       Just for the record, after a couple of months of doing other stuff i found...  my ip return banjo WAS actually cracked (a micro crack at the small tube for the injector returns).        I replaced it  with a banjo fitting (single tube) from a fuel line replacement kit and added a stainless T fitting (1/4 1/4 1/8) for the injector returns to meet into the return hose.       

  Definitely is a low-pressure fitting or fuel would have been spewing everywhere when I was driving around with that. 

[libbydiesel]

Ja, them is inches... inches of ATF.

40 inches of ATF should be about 46" of water ("WC). (40/.87)

46 / 27.7 = 1.66psi.   So, the banjo outlet is handling ~1.7psi.  


12/.87 = 13.8" of vacuum due to the tank means the IP out bolt orifice is actually outputting 59.8" WC of pressure, or 2.2psi... but the tank vacuum lowers the pressure in the fitting.

Your math might be a little off.  A lower specific gravity (0.87) will result in the higher reading, no?  Mercury has a much higher specific gravity than water and an inch of mercury is proportionately more pressure than an inch of water...  Shouldn't the 40 inches of ATF be multiplied by the specific gravity rather than divided by it?  That would mean 1.26 psi rather than 1.66 psi.  Regardless, the pressure is minuscule. 

[TylerDurden]

Yes, quite right!