Fuel Pressure test

[twoseater]

Hello - I just placed a test gauge on my fuel line and the needle jidders between 4-8 when idleing. Should the needle be very steady or is this bouncing around expected. You almost can't get a reading as it vibrates so much. I hope the answer is it should be steady as that may solve some problems that I have been experiencing!

 

[mdazzo]

i just installed an inline fuel pressure guage,i had the same results.i was told air in the line will cause this.I am not sure if this is the reason.I did bleed the line and the bounce was less but i still do not have a steady needle by the way my guage is not a cheap import...

matt

 

[goertz]

probably normal, as the mechanical pump pumps in spurts, and not really a steady flow until higher rpms.

 

[Vettehead Mikey]

It's completely normal to see this. Some gauges have a small inline needle valve to dampen the fluctuations on the gauge.

4-8 psi is normal, all is well.

 

[twoseater]

Thanks guys - Out of desperation I changed out the fuel pump anyway. My backfire through the carb still exists. As you all indicated it would - the needle bounces with the new fuel pump as well.

 

[vetteboy86]

Just curious, how does one bleed the fuel line? Is it as simple as a brake line is, and what is the procedure?

Thanks

 

[wishuwerehere82]

Just curious, how does one bleed the fuel line? Is it as simple as a brake line is, and what is the procedure?

Thanks

On a carbureted engine like most of the C3's, there is no bleeding necessary as the air purges out through the float valve.