Mechanics

ENGINE COMPUTER

2001 Nissan Altima • 150,000 miles

I unplug the spark plug wire and the spark plug to see if there a fire started when I turn on the engine but can't see the plug fire if there a engine computer send a signal to the spark plug, the distribuitor is new
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Junior64
September 17, 2012.



SYSTEM DESCRIPTION
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the engine.

The ignition timing data is stored in the ECM. This data forms the map shown.

The ECM receives information such as the injection pulse width and camshaft position sensor signal. Computing this information, ignition signals are transmitted to the power transistor.

E.G, N: 1,800 rpm, Tp: 1.50 msec A °BTDC

During the following conditions, the ignition timing is revised by the ECM according to the other data stored in the ECM.

At starting
During warm-up
At idle
At low battery voltage
During acceleration

The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed within the anti- knocking zone, if recommended fuel is used under dry conditions. The retard system does not operate under normal driving conditions.

If engine knocking occurs, the knock sensor monitors the condition. The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.

Wrenchtech
Sep 17, 2012.
Did you check the crank position sensor and are there any trouble codes?
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KHLow2008
Sep 18, 2012.

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