How to find the source of air getting into my fuel system?

[advlars]

My truck was running great, but I took it on a drive and it seemed to have lost all power between idle and boost. If you punch the accelerator it will do absolutely nothing for up to 5 seconds and then start to gain power. once its revved up in runs fine (maybe just a bit less power than usual). If I crack my injectors, this symptom goes away for a while, but starts to come back.

Presumably Ive got an air leak somewhere then right??

Is there any way to determine whether this happening between the pump and the injectors, in the pump itself, or somewhere between the gastank and the injector pump?

Fwiw, I replaced my fuel filter and every rubber fuel line in the engine compartment recently so I dont think its the lines there. My primer doesnt seem to work, but I was able to prime it with a transfer pump when i did that work.

Any thoughts on where to start here?

Lars

 

[chapel gate]

Replace the primer.

 

[mudgudgeon]

If your primer doesn't work, I'd bet my house that that's your problem
Run clear hose from primer assembly to the injection pump

 

[asutherland]

Mine was coming in the small O ring on the water drain. Along with the 2 small O rings on the fuel heater. As Chapel gate says, I hear that often the primer pump itself will leak air... only way is to replace the filter / pump assembly. Not cheap but not terribly expensive of a fix either, and easy to do.

 

[advlars]

Looks like you guys got me on the right track. I put a section of clear line in my transfer pump and im getting no bubbles from the gastank to the filter assy and lots of bubbles when I pump hard post- filter assembly. Anybody got any suggestions for temporary fixes or replacement assemblies available in the US? Seems like all the parts i need are in australia...

Ive tried JB welding a pvc cap over the top of the top of the primer knob to seal it up for now but havent had any luck so far. Not that Im terribly surprised by that....

 

[advlars]

Anybody ever switched over to something like this?

Amazon.com: GOLDENROD 496-3/4 WATER-BLOCK FILTER (56591) Bowl Fuel Tank Filter with 3/4" NPT Top Cap: Automotive

Im not thrilled about giving up the heater, water sense alarm, etc. from the stock setup but this looks like an ok option maybe?

 

[mudgudgeon]

If you've got a reliable source of clean fuel, temporarily bypass the filter with fuel hose while you source a replacement.

 

[advlars]

hmm... Ive never cleaned out my tank and my last filter was pretty dirty. But maybe I can run it around the block a few times like that and confirm for sure that that is the cause of the problems and its not something else.

 

[mudgudgeon]

You could always put a $5 in line filter in the hose if you're worried

 

[tweeek]

Confirm it's the primer by bypassing it, then order it from partsouq.com it will be on your doorstep in a couple days.

 

[GTSSportCoupe]

Good ideas, but yes, PLEASE at least run a cheap in-line filter while you do the test. It's really not worth the chance of debris making it's way into the pump or injector nozzles. Having rebuilt my own injectors, I can tell you it only takes the tiniest little bit of anything to screw them up.