Injectors

DTC No. P0201 - P0206:

INJECTORS:

OPERATION
- The injector is an injection nozzle with a solenoid which injects fuel according to the injection signal coming from the engine control module.
- The injector has a fixed nozzle opening area and the fuel pressure against manifold inside pressure is regulated to a fixed level. Therefore, the volume of fuel injected by the injector is determined by the time during which the needle valve is open, namely, by the time during which the solenoid coil is energized.
- The battery positive voltage is applied through the MFI relay to this injector. When the engine control module turns on the power transistor in the unit, the solenoid coil is energized to open the injector valve, which then injects fuel.

TROUBLESHOOTING HINTS

Hint 1: If there is a problem with starting while the engine is warm, perform the combustion test and check for leakage of the injectors.

Hint 2: If the engine can't be started and the injectors are not activated during cranking, the cause is probably a malfunction such as described, not a problem with the injectors.
1. Malfunction of power supply circuit or ground circuit of engine control module
2. Malfunction of MFI relay
3. Malfunction of crankshaft position sensor and/or camshaft position sensor

Hint 3: If there is a cylinder for which the idling condition does not change when, during idling, the fuel injection of the injectors is cut off in sequence, check that cylinder as describe.
1. Check the injector and harness
2. Check the spark plugs and the high-tension cable.
3. Check the compression pressure.

Hint 4: If the injector activation time is outside the standard value even though the results of the checking of the injector's harness and of the injector itself are normal, the cause is probably one of the following.
1. Incomplete combustion inside a cylinder
(Malfunction of spark plugs, ignition coil, compression pressure, etc.)
2. Increased engine resistance

Drive Time:

Long-term Fuel Trim:

Short-term Fuel Trim:

Fuel Control Condition:

INSPECTION USING SCAN TOOL

Wave Pattern Inspection Using an Analyzer

Measurement method
1. Disconnect the injector intermediate harness, and connect the special tool (harness connector MD998474).







2. Connect the oscilloscope probes according to the details given in the table.

Alternative method (when test harness is not available)
Connect the analyzer special patterns pickup to ECM terminals (1), (2), (3), (14), (15) and (16).





Standard wave pattern

Wave pattern observation points




Point A: Height of injector coil induced voltage




Point B: Injector drive time
- The injector drive timing will synchronized with the scan tool display.
- When the engine is suddenly raced the drive time will be greatly extended at first, but the drive time will soon match the engine speed.

HARNESS INSPECTION




STEP 1. Check for continuity between the injectors and the MFI relay.
- Injector intermediate harness connector: Disconnected
- MFI relay connector: Disconnected

NOTE: Touch the ohmmeter probes to both ends of the harness.

OK: GO TO STEP 2
NG: Repair the harness. (A8 - B1)




STEP 2. Check for an open circuit or a short-circuit to ground between the injector and the engine control module.
- Engine control module connector: Disconnected
- Injector intermediate harness connector: Disconnected
OK: STOP
NG: Repair the harness. (A1 - 24, A2 - 9, A3 - 1, A5 - 25, A6 - 10, A7 - 2)

INJECTOR CHECK
Measuring Resistance Between Terminals




1. Disconnect the injector intermediate harness.







2. Measure the resistance between the terminals.
3. Connect the injector intermediate harness.