Diagnostic procedure
WARNING: This page is about a different car, the 2005 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
NO. 4 HARD TO START/LONG CRANK/ERRATIC START/ERRATIC CRANK DIAGNOSTIC PROCEDURE
| STEP | INSPECTION | RESULTS | ACTION | ||||
|---|---|---|---|---|---|---|---|
| 1 | Inspect for the following:
Are all items normal? |
Yes | Go to the next step. | ||||
| No | Service if necessary. Repeat Step 1. |
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| 2 | Connect WDS or equivalent to DLC-2. Turn ignition switch to ON position (Engine off). Retrieve any DTCs. Are there any DTCs displayed? |
Yes | DTC is displayed: Go to appropriate DTC test. |
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| No | No DTC is displayed: Go to the next step. |
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| 3 | Is engine overheating | Yes | Go to symptom troubleshooting "NO. 17 COOLING SYSTEM CONCERNS - OVERHEATING ". | ||||
| No | Go to the next step.(1) Go to Step 5.(2) |
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| 4 | Inspect ignition coil related harnesses condition (intermittent open or short circuit) for all cylinders. Are all harnesses condition normal? |
Yes | Go to Step 6. | ||||
| No | Repair suspected wiring harness. | ||||||
| 5 | Inspect for cracks on high-tension leads. Are there any cracks on high-tension leads? |
Yes | Repair suspected high-tension leads. | ||||
| No | Go to the next step. | ||||||
| 6 | Inspect spark plug conditions. Is spark plug wet, covered with carbon or grayish white? |
Yes | Spark plug is wet or covered with carbon: Inspect for fuel leakage from fuel injector. Spark plug is grayish white: Inspect for clogged fuel injector. |
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| No | Install spark plugs on original cylinders. Go to the next step. |
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| 7 | Visually inspect CKP sensor and teeth of crankshaft pulley. Are CKP sensor and teeth of crankshaft pulley normal? |
Yes | Go to the next step. | ||||
| No | Replace malfunctioning parts. | ||||||
| 8 | Remove and shake PCV valve. Does PCV valve rattle |
Yes | Go to the next step. | ||||
| No | Replace PCV valve. | ||||||
| 9 | Attempt to start engine at part throttle. Does engine run smoothly at part throttle? |
Yes | Inspect electronic throttle control system operation. | ||||
| No | Go to the next step. | ||||||
| 10 | Install fuel pressure gauge between fuel pipe and fuel distributor. Short check connector terminal F/P to body GND using a jumper wire. Turn ignition switch to ON position. Is fuel line pressure correct with ignition switch ON? (See FUEL LINE PRESSURE INSPECTION .) |
Yes | Go to the next step. | ||||
| No | Zero or low: Inspect fuel pump relay and fuel pump circuit. Inspect for clogged fuel line. If okay, replace fuel pump unit. High: Replace fuel pump unit. |
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| 11 | Is fuel line pressure held after ignition switch is turned OFF? (See FUEL LINE PRESSURE INSPECTION .) |
Yes | Go to the next step. | ||||
| No | Inspect fuel injector. If fuel injector is okay, replace fuel pump unit. |
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| 12 | Disconnect a vacuum hose from purge solenoid valve and plug opening end of vacuum hose. Attempt to start engine. Is starting condition improve |
Yes | Inspect if purge solenoid valve is stuck open. | ||||
| No | Go to the next step. | ||||||
| 13 | Inspect MAF sensor for contamination. Is there any contamination? |
Yes | Replace MAF sensor. | ||||
| No | Go to the next step. | ||||||
| 14 | Is there restriction in exhaust system? | Yes | Inspect exhaust system. | ||||
| No | Go to the next step. | ||||||
| 15 | Inspect engine condition while tapping EGR valve housing. Does engine condition improve? | Yes | Replace EGR valve. | ||||
| No | Go to the next step. | ||||||
| 16 | Inspect starting system. (See STARTER INSPECTION .) Is starting system normal? |
Yes | Inspect for loose connectors or poor terminal contact. If okay, remove EGR valve and visually inspect for mechanically stuck EGR valve. | ||||
| No | Repair or replace components as required. | ||||||
| 17 | Verify test results.
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