System Inspection
System Inspection
1. Check blocking of intake system
(1) Visually/physically inspect the blocking in intake system for following items
> Throttle body gasket and damage
> Blocking in intake manifold and injector caused by any foreign substance
(2) Has a problem found ?
2. Check Fuel Pressure.
NOTE:
1. Be cautious that Fuel is explosive and an empty fuel tank can still contain explosive gases. When working on fuel system make sure to supply adequate ventilation to the work area. Do not smoke, and keep sparks and open flames away.
2. The fuel system remains under pressure when the engine is not running. Release fuel system pressure before disconnecting any fuel line to reduce the chance of personal injury or fire damage to vehicle components.
(1) IG "OFF" and disconnect Fuel Pump Relay in Junction Box.
(2) Start-up and wait until it stops itself.
(3) IG "OFF" and connect Fuel Pump Relay.
(4) Install the fuel pressure gauge to the delivery pipe with the fuel pressure gauge adaptor.
(5) Activate the fuel pump, and with fuel pressure applied, check that there is no fuel leakage from the pressure gauge or connection part.
(6) Measure the fuel pressure at idle.
Specification : 374.6 - 384.4 kPa (3.82 - 3.92 kg/cm2, 54.3 - 55.8 psi)
(7) Is the measured fuel pressure within specifications ?
3. Check fuel leakage in injector
(1) IG "OFF" after checking the fuel pressure test.
(2) Stop engine and check for a change in the fuel pressure gauge reading for 5 minutes.
Specification : After engine stops, fuel gauge reading is maintained for 5 minutes.
(3) Is the fuel gauge reading maintained ?
4. Check MAFS
(1) IG "OFF" and install a scantool
(2) ENG "ON" and monitor "MAFS" data on the service data.
(3) Monitor signal waveform at terminal 1 of MAFS with scantool.
Specification : Signal waveform will be displayed as follows.
(Be aware that the signal of MAFS is not voltage display but frequency display.)
fig 1) Idle
fig 2) Acceleration
(4) Are both service data and signal wave form dispayed correctly ?
