leaking injector

[2deuce]

I found this out while testing my trans cooler. The injector doesn't leak at idle but does at full throttle. I checked the return lines and tightened the main line connection without any success. I found the leak immediately after a hard run. It stops when idling so I cant see where its coming from, just where it has been dripping on the manifold. The truck runs fine with the leak. I'm thinking I need a new injector, but are the return lines subject to a higher pressure above idle? Wanted to check here before I change out the injector.
Thanks

 

[84cucv1ton]

there is a copper washer under the injector. did you try tighten down whole injector? think its a 3/4.

 

[2deuce]

Looking where its been leaking appears to be around the return lines or about the middle of the injector. I don't have a socket to tighten the injector. I replaced all my injectors recently with these newer ones with a borrowed socket, which I need to borrow again. I put in new washers at that time. I did tighten the supply line connection to where its real tight, that is 3/4. It could still be a return line leaking. How much fuel flows thru the return line at idle as opposed to half throttle? The leak stops at idle, but drips fast going down the road to where theres a cloud of vapor evaporating off the hot manifold. A high risk of fire, I think. I don't know the combustion point of diesel. I drove it today 4 miles knowing full well it was leaking. I don't think I'll take any chances tomorrow, I'll get a ride to work.