Fuel Pressure Gauge Bleed out

[JAG1]

Any one know if an Isspro F/P gauge can be disconnected at the back to bleed off the air and then reinserted and retightened without buying a new compression wring? I'm not aware of how the plastic tube is sealed whether a compression wring like plumbing or what

[Mopar1973Man]

Don't bother. You can bleed it out but it will get air bubbles again. What's your fuel pressure?

[JAG1]

Okay thank you. It's bouncing around sometimes and too low pressure when cold but takes way too long to get to the 19 it's set at so I'm changing the big filter again to see what happens.

[dripley]

I just let the lift pump fill up the line and attached it. You could do that again with the compression ring still on the tube. It should be good for more than one use.

[Mopar1973Man]

Remember every filter change or anytime you open the fuel system you're going to introduce air back to that line so bleeding is just a temporary fix.

[dripley]

I bled mine when I installed the gauge and have not since. The only time I saw any pressure difference was when I changed the pump after it failed. Lost about a 1 pound of pressure after installing the new pump. It has remained mostly stable like before.

[JAG1]

Thanks all. Just changed both filters and no difference big filter has built in air bleed and did that but erratic F/P has showed its ugly face again after months of steady pressure at 19. Thought this problem was solved . Going to the auto parts store and see if a run will make a difference.

 

I got an air leak on the suction side, has to be there somewhere as a leak would show on the pressure side of lift pump. wondering about those Quick connects... I heard sometimes are a problem.

 

 

Update:

I found  problem... Before my run to the store I moved the quick connect at the draw straw shoved it tighter spun it back and forth. I started up and knew right away the problem was gone. Gauge was smooth and went all the way to 17. No bouncing around. After a few miles gauge showed a steady 19. That's back to normal now.

 

Finally narrowed it down

Edited September 24, 2017 by JAG1

[dripley]

I have of late noticed a little vibration in mine. I do mean little, you have stare at the gauge to see it. Pretty sure mine is the needle valve. I believe the seat in the valve is going on its way out. When tighten it it just seems the seat is hard. It is almost like on and off is it. Barely cracking it open is a bit more difficult than it used to be. 

Edited September 24, 2017 by dripley

[JAG1]

I think you can unscrew the packing nut around the valve stem and remove the valve that way, Instead of redoing the whole thing. Might be a replaceable valve tip needle or something.

[Mopar1973Man]

Another idea. Leave the valve alone and pick up a snubber from ISSPro and install it after the valve. This way you can still shut the line down and the snubber does the job of the cracking the needle valve. 3 years now and ZERO issues on ISSPro electric gauge. 

 

[dripley]

I will look into that.

[Mopar1973Man]

You can see the snubber on the end of the needle valve...