How to fill mechanical fuel pressure gauge tubing
 

Any ideas on what to fill the plastic tube with from the isolator to the gauge? I got a syringe with gauge, but it won't fill fully and takes multiple refills the fill the line. Each refill introduces air into the line. I'd like to figure out a way to fill and flush the line of air without refilling. I'm pretty sure that air in the line is causing an exaggerated reading of low fuel pressure.

Well being I don't work with isolators...

But if a person was to want to purge the coolant side you would have to have a small amount of pressurized coolant and plug in at the fill port and loosen the other end. Adding pressurized coolant to the system till the coolant leaks out at the gauge. Tighten your fitting. Then add a bit of pressure and release. Plug it and you should be ready. You could most likely setup a garden sprayer for something like this.

Crazy idea... :w2:

Use anti freeze :c:

Does it magically just install itself in the tubing? :w2:

I can see how the opening question was not clear. I was asking how to fill it whether than what to fill it with.

You will never get all the air out. Mines the same way and it works as it should.

Unhook the line from the isolator and use your mouth to suck the fluid up to about an inch from your mouth and hold it there while you hook the tubing back up, then you can fill it the rest of the way with your syringe. :c:

I like the idea of eliminating the isolator. Diesel not that flammable anyway.

But it makes a mess and I don't want raw diesel spraying in the cab of my truck. That's why I bought and electrical setup for the other truck

Didn't think about suction. Maybe RV antifreeze. Non toxic and tasteless.

Don't get it in your mouth :nope:

http://i49.tinypic.com/2cy5g02.jpg

Really hard to burst Air Brake Line rated for 600-800 PSI... I seriously doubt anything will happen.

Where did you tap in with the banjo bolt.

Right here at the fuel filter... No longer using nylon so disregard the nylon tubing.
http://articles.mopar1973man.com/ima...stem-banjo.jpg

I want to re-do this hook up and get back under the stock filter housing again. Because the stock filter acts like a water hammer suppressor.
http://articles.mopar1973man.com/ima...re-bigline.jpg

Doesn't look familiar. Must be different setup. I'm 2001.5.

OK but is it rated for fuel ? Don't actually have to burst it, somthing could rub through it.
I think I don't want a pressurized fuel line in my cab,:nope: but thats just me. :c:

I realize that the banjo bolt is cummins specific, but are the fittings and needle valve, etc. automotive specific or more like Home Depot/lowes variety? I see Geno's has a banjo bolt that fits into the schrader valve so that the schrader valve is still viable for pressure testing. Looks like a good place to tap in.

Not ready to scrap the isolator yet, but the gauge is now not reading any pressure at all. Runs fine, so I doubt it's accurate.

Everything in the picture plumbing wise is a NAPA part store thing.

The banjo bolt is from...
http://www.vulcanperformance.com/Tapped-Banjo-Bolt-p/tbb.htm

Late,but may help someone as I just did this myself.

You can use a funnel with different sizes hoses to fit the 1/8 plastic line. Loosen the bottom where the line goes into the isolator and pour the anti-freeze into the funnel from the top. The line will fill with anti-freeze top to bottom, and no air. Close line to isolator (bottom) when finished. A second person as a helper will keep you from spilling anti freeze.

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If you still have an inch or so of air in the top of the tubing's line, use the syringe. Fill the syringe maybe 1/3 anti freeze(push out air) and use the syringe as a suction device. Get a tight seal on the tubing and use the suction to move the fluid from the tubing into the body of the syringe. Once you have all anti freeze fluid in the tubing, push anti freeze fluid back into the tubing with the syringe. Works like a charm.