Knocking after injector change

[Nero]

Three hours can be sufficient time for it to cool off.
In my old man's old truck, when the pump was going out, we'd go to the store, be in there for 15-20 minutes, and it wouldn't restart. Cold water trick fired it up.

 

[Rdnck84_03]

It sounds to me like you're likely getting air intrusion.

James

 

[Rupert8]

Air intrusion. Right. We'll, I replaced all the fuel return lines recently. Where else are common points of ingress? I'll look into that.

 

[Nero]

Fuel return leakage. Some people even put a check valve in the main return at the back of the drivers side head too.
Otherwise common paces are the sealing olives on the hard lines, loose filter, fuel heater connector leaking...

 

[94f350]

I had a similar issue on my truck, started out with a really bad leak out the injectors because I replaced the o rings incorrectly, said "**** it" for a few days and one day I started it up after running it for a few hours and it knocked like a ************ until I shut it off, then ran fine, I fixed the fuel leak, then the truck ran great. I think you might just have a bad injector. I'd throw the old ones back in and see what happens. Your IP could also just be wore out because the new injectors are gonna take more pressure to pop than old ones. Might be a good idea to pull the fuel filter off and fill it with atf and see what it does, maybe throw some in the tank too. Hope this helps.