Checking For Air In Your Fuel
There are many ways to check for air in your fuel, in this article I’ll name off the more common ones.
Loosening Bleed Bolt method
Then locate the bleed bolt on the top of the fuel filter housing and loosen it a couple turns.
Now locate the primer on the lift pump.
Pump the Primer on the lift pump and check for air bubbles coming out of the bleed bolt. If bubbles continue to come out of the bleed bolt while you are priming, you likely have air in your fuel.
Return line into Jug method.
This is my preferred method, however it does require the engine to be running.
Normally the return from the Injector Pump gets fed back into the tank. What we are going to do is redirect it into our own container, that way we can watch for air bubbles coming out.
To do this, we are going to splice into the return line with our own chunk of hose, you can see a good location to splice into in this picture
You are connecting to the rubber side of the hose, the hose size is 5/16”. The chunk of hose you connect to that one will need to be long enough to reach wherever you have the container.
Now start up the engine, and watch for bubbles coming out of the line, a couple large bubbles at first are normal, but if it continues to spit out small bubbles, you likely have air in your fuel.
To diagnose where your air leak is, go here: Finding & Fixing Your Air Leak.