Check blocking of intake system
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
Has a problem found?
YES
▶ Repair or replace it, and go to "Verification of Vehicle Repair" procedure.
NO
▶ Go to " Check fuel pressure" as follows.
Check fuel pressure
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 presonal injury or fire damage to vehicle components.
IG "OFF" and disconnect Fuel Pump Relay in Junction Box.
Start-up and wait until it stops itself.
IG "OFF" and connect Fuel Pump Relay.
Install the fuel pressure gauge to the delivery pipe with the fuel pressure gauge adaptor.
Activate the fuel pump, and with fuel pressure applied, check that there is no fuel leakage from the pressure gauge or connection part.
Measure the fuel pressure at idle.
Specifications : 374.6 ~ 384.4 kPa(3.82 ~ 3.92 ㎏/㎠, 54.3 ~ 55.8 psi)
Is the measured fuel pressure within specifications ?
YES
▶ Go to "Check fuel leakage in injector" as follow.
YES
▶ Repair or replace according to the below table. And then, go to " Verification of Vehicle Repair"procedure.
Condition | Possible cause |
Fuel Pressure is too low | Fuel filter,fuel pressure regulator, in-tank fuel hose or the fuel pump |
Fuel Pressure is too high | Fuel pressure regulator, hose or pipe |
Check fuel leakage in injector
IG "OFF" after checking the fuel pressure test.
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.
Is the fuel gauge reading maintained ?
YES
▶ Go to "Check MAFS" as follows
NO
▶ There is a fuel leakage in injector. Replace it, and go to " Verification of Vehicle Repair" procedure.
Check MAFS
IG "OFF" and install a scantool
ENG "ON" and monitor "MAFS" data on the service data.
Monitor signal waveform at signal terminal 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
Are both service data and signalwave form dispayed correctly ?
YES
Clear DTC and Test-drive under enable conditions above-mentioned. After the test, If this DTC is set, go to "Inspection & Repair" procedure. If not, troubleshooting is completed.
NO
Substitute with a known - good MAFS and check for proper operation.
If the problem is corrected, replace MAFS and go to "Verification of Vehicle Repair" procedure.
