Fuel Cut Control System Inspection - Mazda MX-5 Miata Sport 2007 Manual

2007 ENGINE PERFORMANCE Symptom Troubleshooting - MX-5 Miata
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FUEL CUT CONTROL SYSTEM INSPECTION

NOTE:
This inspection has to perform after the Fuel Injector Operation Inspection.

If simulation function of M-MDS is used:
1. Warm up the engine and idle it.
2. Connect the M-MDS or equivalent to DLC-2.
3. Select the RPM and FUELPW1 PIDs.
4. Monitor the both PIDs while performing the following steps.
1. Depress the accelerator pedal and increase the RPM PID to 4,000 rpm.
2. Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the FUELPW1
PID is 0 ms. , and 2-5 ms. when the RPM PID drops below 1,200 rpm.
If not as specified, inspect the following.


2007 Mazda MX-5 Miata Sport
Perform main relay
operation inspection.
Is main relay operation
normal?
Switch fuel injector
connector of not
operating fuel injector
with operating fuel
injector.
Is operation sound heard?
Are wiring harness and
connectors of not
operation fuel injector
normal? (Open or short)
ECT sensor and related harness
(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION
Go to Step 3.
Yes Inspect the following:
Fuel injector power

system related
wiring harness and
connectors
PCM connectors

Fuel injector GND

and related wiring
harness and
connectors
No Repair or replace
malfunctioning parts.
Yes Go to the next step.
No Replace the fuel injector.
Yes Inspect PCM terminal
voltage of fuel injector
signal.
No Repair or replace
malfunctioning parts.