Nissan Cefiro A32 engine idle shake fault
A 97-year Nissan Cefiro A32 sedan (engine type VQ30DE, VIN code: JN1CCUA32V0001253), at the start, feeling the body shake, when start and first gear change to second gear, the fault is most obvious, middle, high speed vehicle operation normal.
Fault Diagnosis and Analysis:
First use Consult3 III read fault code, the system displays normally. Read the main parameters data stream as follows:
Camshaft sensor angle signal: 825RPM
Air flow sensor: 1.32 V
Coolant temperature sensor: 89 ℃
Battery voltage: 13.6 V
Throttle position sensor: 2.52 V
Throttle fully closed position: OFF
Air conditioner switch signal: OFF
Injector pulse width: 3.7MS
Ignition timing: 19BTDC
Idle Control Valve: 36.0%
According to the data stream can be seen: the problem is the throttle body position sensor did not adjust well or throttle body too dirty. Then, remove the throttle body cleaning and adjusting the throttle position sensor, cleaning fuel injectors, replace spark plugs and fuel filter. After installed test the car, the fault persists. Next, check the EGR system and activated carbon canister control system, no problems found. Use Nissan Consult Diagnosis Interface to measure the sensor signals, also no problems found. Finally would be analyzed the fault by measuring the exhaust.
Exhaust emission data are as follows: CO is 1.3%, HC is 600 × 10-6, for electric vehicles is clearly excessive; then measure the ignition waveform found: each cylinder high-pressure significantly weaker, at around 8 KV, through the exhaust and ignition waveform analysis, the problem is clearly in the high-pressure part, is high-pressure fire energy weakened caused by the engine power insufficient.
It has replaced six ignition, but fault persists. Check the ignition system according to the circuit diagram found that the ignition system have capacitor by itself, then think whether the capacitor damage caused by the failure? With this problem to check capacitors. Remove and measure the capacitor, found it breakdown, the primary voltage from here to the grounding, thus weakening the ignition energy.
Troubleshooting: Replace capacitors, test the car, fault disappears.
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