Fuel System (MZI-3.7): Overview Mazda CX-9 I

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Operation Test

1. Follow "BEFORE SERVICE PRECAUTION" before performing any work operations to prevent fuel from spilling from the fuel system. See «BEFORE SERVICE PRECAUTION [MZI-3.7]».
2. Remove the fuel-filler cap. See «FUEL TANK REMOVAL/INSTALLATION [MZI-3.7]».
3. Start the fuel pump using the following procedure

Using M-MDS

Scheme 5

Scheme 6

1. Connect the M-MDS to the DLC-2.
2. Turn the ignition switch to the ON position.
3. Using the simulation function FP, verify that operation sound is heard from the fuel pump when FP is turned from OFF to ON. If the operation sound cannot be verified, measure the voltage at fuel pump wiring harness-side connector terminal B. If as specified, inspect the following: Fuel pump continuity If not within the specification, inspect the following: Fuel pump relay Wiring harnesses and connectors between battery-fuel pump relay-fuel pump Standard B+ (Ignition switch at ON) Without using M-MDS Disconnect the negative battery cable. See «BATTERY REMOVAL/INSTALLATION [MZI-3.7]». Remove the fuel pump relay. CAUTION: Short the specified terminals because shorting the wrong terminal of the main fuse block may cause malfunctions. Using a jumper wire, short fuel pump relay terminals C and D in the main fuse block. Connect the negative battery cable and operate the fuel pump. Verify that operation sound is heard from the fuel pump when ignition switch turn to the ON position. If the operation sound cannot be verified, measure the voltage at fuel pump wiring harness-side connector terminal B. If as specified, inspect the following: Fuel pump continuity If not within the specification, inspect the following: Fuel pump relay Wiring harnesses and connectors between battery-fuel pump relay-fuel pump Standard B+ (Ignition switch at ON) Disconnect the jumper wire.
4. Complete the "AFTER SERVICE PRECAUTION". See «AFTER SERVICE PRECAUTION [MZI-3.7]».

1. Carry out the "Fuel Injector Operation Inspection". See «ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7]». If not as specified, perform the further inspection for the fuel injectors.

Scheme 7

1. Turn the ignition switch to LOCK position.
2. Disconnect the negative battery cable. See «BATTERY REMOVAL/INSTALLATION [MZI-3.7]».
3. Remove the engine cover. See «ENGINE COVER REMOVAL/INSTALLATION [MZI-3.7]».
4. Remove the dynamic chamber. See «INTAKE-AIR SYSTEM REMOVAL/INSTALLATION [MZI-3.7]».
5. Disconnect the fuel injector connectors.
6. Measure the resistance of the fuel injector. If not as specified, replace the fuel injector. See «FUEL INJECTOR REMOVAL/INSTALLATION [MZI-3.7]». If as specified but "Operation Test" is failed, carry out the "Circuit Open/Short Inspection". Inspect for open or short circuit. Fuel injector resistance 11-18 ohms

Scheme 8

Scheme 9

Scheme 10

1. Disconnect the PCM connector.
2. Inspect the following wiring harness for open or short (continuity check).

Open circuit

1. If there is no continuity, the circuit is open. Repair or replace the harness. No. 1 cylinder fuel injector terminal A and PCM terminal 2BJ No. 2 cylinder fuel injector terminal A and PCM terminal 2BM No. 3 cylinder fuel injector terminal A and PCM terminal 2BF No. 4 cylinder fuel injector terminal A and PCM terminal 2BH No. 5 cylinder fuel injector terminal A and PCM terminal 2BB No. 6 cylinder fuel injector terminal A and PCM terminal 2BD No. 1 cylinder fuel injector terminal B and fuel pump relay terminal D No. 2 cylinder fuel injector terminal B and fuel pump relay terminal D No. 3 cylinder fuel injector terminal B and fuel pump relay terminal D No. 4 cylinder fuel injector terminal B and fuel pump relay terminal D No. 5 cylinder fuel injector terminal B and fuel pump relay terminal D No. 6 cylinder fuel injector terminal B and fuel pump relay terminal D

Short circuit

1. If there is continuity, the circuit is short. Repair or replace the harness. No. 1 cylinder fuel injector terminal A and body ground No. 2 cylinder fuel injector terminal A and body ground No. 3 cylinder fuel injector terminal A and body ground No. 4 cylinder fuel injector terminal A and body ground No. 5 cylinder fuel injector terminal A and body ground No. 6 cylinder fuel injector terminal A and body ground No. 1 cylinder fuel injector terminal B and power supply No. 2 cylinder fuel injector terminal B and power supply No. 3 cylinder fuel injector terminal B and power supply No. 4 cylinder fuel injector terminal B and power supply No. 5 cylinder fuel injector terminal B and power supply No. 6 cylinder fuel injector terminal B and power supply

Scheme 11

1. Inspect atomization pattern. If the atomization is faulty, replace the fuel injector. See «FUEL INJECTOR REMOVAL/INSTALLATION [MZI-3.7]».

See also:
• PROPELLER SHAFT REMOVAL/INSTALLATION