You won't have to worry about that with an Isolator installed. It is just Anti-Freeze running to the gauge.

As far as I know, my electric Autometer gauge is accurate.

You could always duct tape a fuel pressure test gauge to the windshield. You have to have one with a long enough hose though. Before all these safe fuel pressure gauges for in vehicle use, that was the best way to check it at WOT.

 

Mine is within a couple of psi of my underhood mechanical gauge.

 

I just bought an electric Auto Meter from RandomHero and he said it reads 3-5 psi low compared to a Harbor Freight mechanical one. Haven't hooked it up yet though.

But I am in the same boat, I bought it to check for a pressure drop, not so much to read the exact fuel pressure.

 

At some point I checked the calibration of mine. Mechanical gauge to what it read. It was way off.... low. Called autometer tech support. They wound up sending me another sending unit. It was dead nuts after that.

 

I just checked the side, 0-100 like it should be. I guess Ill call them.

 

Ditto...^^^^

 

Couldnt find a phone number but I sent an email...

 

Post up what you find out, I might follow in your footsteps if you get good results from them.

 

My electric guage has always read about one psi low. But watching a wideband it doesn't matter all that much anyway. You'll know when the pressure drops when it starts to go lean

 

See, I am trying to avoid the whole lean thing