Fuel Leak

[RETed]

Originally Posted by Pete_89T2

1. Both of those lines with the worm gear clamps are fuel. One of them (forget which - consult FSM or just follow the hose to figure it out) connects to the outlet of the fuel filter, and sees high pressure from the pump. The other is the return fuel line back to the tank. Get rid of those crappy worm gear clamps ASAP and get the proper clamps for fuel injection plumbing - the spring OEM type or the T-bolt style band clamps that are rated for this.

Be very careful when using these "t-bolt" style band clamps that are usually labeled as "fuel hose clamps" at the auto parts stores.
(see 1st / left pic below)
Since these clamps are pretty small and the threads on the screw / bolt are pretty small, they are very easy to overtighten.
Once you overtighten, the clamp is damaged and no good.
Once the clamp is damaged, it will loosen and cause a fuel leak.
If you know what you are doing and torque them properly, yes, they are superior versus the typical "worm gear pipe clamps"
(see 2nd / right pic below)
These worm gear pipe clamps are more resistant to overtightening and are superior than the above when overtightened - at least they will not back off and loosen.
(I've had a customer of mine go through this headache a few weeks ago - "t-bolt" clamp leaked [most likely overtightened] and replaced with small "worm drive" pipe clamps.)

If all of that scares you, use the stock-type spring clamps.
I'd recommend to double them up though - that will guarantee it will not leak.
Notice that the stock spring clamps use on the fuel system (if you got the originals) are thicker and "double walled" than the other clamps used on the emissions system plumbing.

Ditto for the hose - you'll also want to check the hose to verify that it is rated for high pressure fuel injection systems, not the cheaper fuel line hose that you can use on carb cars.

Typically you'll see these #'s.

(SAE) 30R7 / J30R7 - this is NOT what you want:
http://www.discounthydraulichose.com.../30r7-hose.htm

(SAE) 30R9 / J30R9 - this is the fuel injection rated stuff you want:
http://www.goodyearep.com/ProductsDetail.aspx?id=5144

The key is the "7" versus "9" in the SAE code #.
I've seen 30R7 with printed "RATED TO 150PSI" on the hose that failed on fuel injection applications.
Ignore the "RATED TO" # - this doesn't mean squat in our case.
(Notice the "Minimum Burst Pressure" rating of "250 psi" in the first link.)
Steady state pressure does not cause the (30R7) hose to fail - it's the pulsation from fuel injection systems that does the damage.
30R7 is not designed to handle the pulsations and pressure fluctuations due to the fuel injectors firing rapidly.


-Ted