Recently, I've noticed my Innovate AFR gauge showing 16-17+ on occasion during cruising or when under minimal load. I'm running on a Hondata s200 map which has been fine for over 2 years.

Tonight on my way home I decided to fill the tank since we had a huge explosion and fire in a gasoline refinery and everyone is filling up just in case (Puerto Rico). I did not fill it to the top though.

When I got home, I detected a strong smell of gasoline so I left the engine running and popped the hood to check for leaks and noticed the pressure was almost at 90lbs on the gauge! I then noticed the garage floor was wet with gas and it was coming from the gas cap. I removed the cap and gas kept spilling on the floor, then stopped.

I turned off the engine and quickly got online to make this post with hopes someone can lead me in the right direction.

Where should I start?

1) Gas tank?
2) Walbro 255 in tank pump?
3) Fuel filter?
4) Fuel regulator?
5) Fuel return line?
6) Fuel lines?

If gas is under pressure in the fuel tank what of the above could cause this?

 

Clogged fuel return line sounds like a reasonable culprit here.

 

Sounds reasonable. How can I test for this? Do I have to drop the gas tank? It's a 1989 Civic hatch.

BTW, I tried adjusting the FPR but the dial on the gauge does not move. Also, when I rev the engine with my hand on the throttle body, the pressure does not change and I know it should go up.

 

Wow, ive never heard of that problem before?!
Id pull off the fuel pressure regulator and look at it, Maybe it somehow failed and is causing yourfuel pressure to skyrocket...I still cant picture how the tank is getting pressurized and overflowing out of your gas cap opening

 

Sounds like the pump is what they call "deadheaded", meaning the return line is completely blocked and your at max possible fuel pressure...
Any other weird issues happening that may have started recently?