fuel pressure?? if it is fuel injected it should be on the end of the fuel rail.
there should be a valve on the fuel rail on the engine that you release the pressure, it looks just like a tire valve.
no pressure release valve
Relese the pressure by pushing the schrader valve under the hood on the right side of engine.
Valve clearance for a Honda GC160 engine; Inlet 0.15 +/- 0.04mm Exhaust is 0.20 +/- 0.04mm
Replace the PCV Valve.
On a 1985 Honda Civic, the PCV valve is situated on the firewall side of the engine. The valve is connected to the rubber hose.
In the valve cover
intake valve 0. 20mm exhaust valve 0. 25mm
The EGR valve for a Honda EX 1991 is at the top of the engine. It is at the front, just to the left of center.
UNDER HOOD, CENTER, UPPER ENGINE AREA, TOP OF ENGINE, MOUNTED IN VALVE COVER
Back pressure regulates the release of exhaust into a slower stream that keeps the exhaust valve temperature more consistent.
the hose that is connect to your engine.