Test fuel pressure with a tire gauge?

[brianl703]

Originally Posted By: johnd
I just use my AC gauge set. Works fine and since it screws on, no leaking.


GM does use the same fitting on the fuel rail as an R12 low side port. Even my 2006 Saab 93 has that same fitting.

Aren't you supposed to leave the lines on an AC gauge set pressurized when you're not using it to keep contaminants out?

 

[mobimation]

Originally Posted By: labman
I am not sure how the pencil style tire gauges work and if they would measure anything but air. If it is a tapered tube and depends on the viscosity of the fluid, no. A Burbon tube type gauge, which many dial gauges use, is accurate with any fluid. Even a metal one may have rubber seals gasoline would ruin.


On needs to have a healthy respect for how flammable gasoline is.

And in many cases there is some 350PSI pressure so could be a challenge assuring that the hose will not burst off and spray gasoline all over the engine bay.
This could lead to a very rapidly escalating fire for which the mechanic is not prepared. Could result in burnt down houses, badly burnt humans, destroyed cars. Better safe than sorry. Always think twice of assuring some margin.

 

[JetStar]

Originally Posted By: labman
I am not sure how the pencil style tire gauges work and if they would measure anything but air. If it is a tapered tube and depends on the viscosity of the fluid, no. A Burbon tube type gauge, which many dial gauges use, is accurate with any fluid. Even a metal one may have rubber seals gasoline would ruin.


Ah, that would be a Bourdon Tube.