Fuel Pressure Gauge reads 0psi....why?

[DMcLeod]

I have a pricol gauge with isolator to monitor the LP. I have a needle valve cracked open at the banjo fitting and an 18" hose to the isolator mounted off the master cylinder stud. The setup has worked great up until a couple of weeks ago when the gauge began to read only a couple of pounds. I immediately checked the pressure with a test gauge - it was fine. Now, the gauge needle doesn't move (actual pressure is still good). I bled the fuel side of the isolator - no change. The semi-clear tubing between the isolator and gauge appears to still be full of glycol and no leaks.



Those of you who have replaced isolators - how did you narrow the problem to the isolator? How does an isolator fail (aside from external leaks, etc)? I suppose I shall figure out a way to test the gauge next. Anyone care to share their experiences or lend advice?

 

[mhenon]

Mine did the same and i found a very slow leak on the glycol side of the isolator. The fuel side had pegged the the diaphram flat to the gauge side so the reading was zero.

I ended up draining the isolator, pushing the diaphram back towards the fuel side and filling the gauge side with anti-freeze. Once everything was hooked back up I bled the fuel side last and it has worked since.

Mike

 

[Dakotahaulers]

Check the four screws that hold the two cases together. They have to be tight or the gauge will not read right. I had same problem and it fixed it just fine. I have had to retighen them a couple of times. Hope it helps.

 

[NoSeeUm]

Have you tried gently pushing in and out on the fuel side of the isolator diaphram using the eraser end of a pencil? You should get a response on the pressure gauge.



Jim

 

[DMcLeod]

Thanks for the replys. Solution: I took the isolator apart and the internal rubber diaphram seemed to be pushed up and stuck against the glycol side of the isolator. I pushed it towards the middle and added glycol before reassemby. I made sure all fasteners are tight. It's working again.