Engine Controls - Basic Testing: Diagnosis Hyundai Accent I

VISUAL INSPECTION

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and are not pinched or cut. See VACUUM DIAGRAMS article to verify routing and connections (if necessary). Inspect air induction system for possible vacuum leaks.

FUEL PUMP TEST

Turn ignition off. Apply battery voltage to fuel pump drive terminal (White/Black wire). (Scheme 18) Remove fuel tank cap and listen for fuel pump operation. Pinch fuel hoses by hand and ensure fuel pressure can be felt.

Scheme 18

Scheme 19

1. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-16591-S17391737122000122900000). Disconnect high pressure fuel hose from top of fuel filter. Cover hose connection using rags to avoid spraying of fuel.
2. Using Fuel Pressure Gauge Adapter (09353-24200 ), install fuel pressure gauge to fuel filter. (Scheme 19) Tighten bolt to 18-25 ft. lbs. (25-34 N.m).
3. Start engine. Ensure no fuel leakage exists at pressure gauge or connection. Disconnect vacuum hose from fuel pressure regulator, and plug hose end.
4. 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 (1) Application At Idle W/ Vacuum psi (kg/cm 2 ) At Idle W/O Vacuum psi (kg/cm 2 ) Accent 37 (2.5) 44 (3.0) (1) Regulated fuel pressure.
5. 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.
6. If fuel pressure is too high, check for sticking valve in fuel pressure regulator, or restricted or bent fuel return hose or pipe.
7. If fuel pressure does not differ when regulator vacuum hose is connected or disconnected, check for restricted/damaged vacuum hose or fitting, or sticking or poor seating valve in fuel pressure regulator.
8. 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.
9. After testing is completed, release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-16591-S17391737122000122900000). 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. (Scheme 18), (Scheme 19), (Scheme 20) or see scheme 4. Check for leaks.

SFI CONTROL RELAY TEST

1. Remove control relay located under left side of dashboard, near fuse/relay block. Apply battery voltage across relay terminals No. 2 (negative) and No. 4 (positive). (Scheme 20) Using ohmmeter, check continuity between terminals No. 1 and 5. Continuity should exist until voltage is disconnected.
2. Reapply battery voltage between terminals No. 2 and 4. Check continuity between terminals No. 3 and 5. Continuity should exist until voltage is disconnected. Replace relay if it fails any test.

Scheme 20