I changed my exhaust and haven't welded the new bung onto the pipe yet, so that's out.

 

That's what it sounds like. Did you run any weird chemicals through it? Or maybe a caterpillar got into the return line? Nope. It would take a lot more pump than what you've got, or I ever used, to do that.

 

This is what I was looking for, do you have any links or further information on what exactly it takes to do that?

 

A MagnaFuel 4303 won't do it. I'd be interested to know if you were able to make the pump run continuously, if the pressure would continue to build. If it did, that would indicate a possible blockage. If it maintains 80 psi, that would indicate a restriction, or partial blockage.

 

I'll be checking the output of the regulator tonight when I get a chance to verify that it is not blocked or collapsed, I'll let you know what I find.

 

Once the regulator sees vacuum, the pressure will come down. KOEO pressure is always higher than KOERunning when using a vacuum referenced regulator.

70psi KOEO is a tad high.

peace
Hog

 

And 80 psi is something to be concerned about.

 

Correct, however using vacuum to control fuel pressure is a band-aid for a serious issue.

Just a bit, it was enough to pop one of my fuel rails off once. I can't imagine what 100+ would damage had I driven it and got into boost, but I don't want to find out.

You were correct. I suspected a regulator failure or blockage so I pulled the return line off the tank at the rear of the car and tested, fuel pressure came down to sane levels. Now I have to pull the tank and find out where the blockage is on the return line.

 

Weird. There wasn't 20 pounds of pressure in the tank, was there?

 

Ha no, there has to be a blockage somewhere between the hardline under the car and the venturi in the tank. I'll troubleshoot that tonight.