Fuel Pressure Test

Release fuel pressure. See FUEL PRESSURE RELEASE . Disconnect high pressure fuel hose from top of fuel filter. Cover hose connection using rags to avoid spraying of fuel.
Using Fuel Pressure Gauge Adapter (09353-24200 ), install fuel pressure gauge to fuel filter. See Fig 1 . Tighten bolt to 18-25 f t. lbs. (25-34 N.m).

Fig 1: Installing Fuel Pressure Gauge
Courtesy of HYUNDAI MOTOR CO.
Start engine. Ensure no fuel leakage exists at pressure gauge or connection. Disconnect vacuum hose from fuel pressure regulator, and plug hose end.

Measure and record fuel pressure at idle. Reconnect vacuum hose, and again measure and record fuel pressure. See FUEL PUMP SPECIFICATIONS table. If measurements are not within specification, go to next step. If measurements are okay, go to step 8).

FUEL PUMP SPECIFICATIONS

Application

Pressure psi (kg/cm² )

Volume In One Min. Pts. (L)

With Vacuum

37 (2.5)

⁽¹⁾

Without Vacuum

44 (3.0)

⁽¹⁾

⁽¹⁾	Information is not available from manufacturer.

If fuel pressure is low, check for: a restricted fuel filter or for leaking fuel to return side. This can be caused by poor seating of valve in fuel pressure regulator or low fuel pump discharge pressure.
If fuel pressure is too high, check for: sticking valve in fuel pressure regulator. Restricted or bent fuel return hose or pipe.
If fuel pressure does not differ when regulator vacuum hose is connected or disconnected, check for: restricted/damaged vacuum hose or fitting. Sticking or poor seating valve in fuel pressure regulator.
If measurements are okay in step 4), stop engine and ensure fuel pressure gauge reading does not drop. If fuel pressure drops slowly after engine is stopped, an injector is leaking. If fuel pressure drops immediately after engine is stopped, check valve inside fuel pump is not closed.
After testing is completed, release fuel pressure. See FUEL PRESSURE RELEASE . Disconnect fuel pressure gauge from adapter bolt. Ensure hose connection is covered by a shop towel to prevent fuel spray. Remove adapter bolt, install new "O" ring, and replace with original bolt. Apply battery voltage to fuel pump drive terminal. See Figure , Fig 1 , Figure or Figure . Check for leaks.