Do-it-yourself auto repair

Cold Start Misfire

Cold Start Misfire

Drivers often face a misfire problem when starting the cold engine. Namely, after starting the turn number is decreased, there is uneven exhaust and smell of unburned fuel, the engine starts to «misfire», and as the engine warms up, the vehicle starts to work smoothly with no visible signs of engine problems. What shall I do, where shall I begin the search for problems? This is not clear. In this case you should look for the engine misfire cause. Follow the instructions set out below.

7 Reasons for Cold Start Misfire

  1. To begin, turn out glows and see how things are going with soot. After all, any experienced mechanic knows that the glows (their color) can be said a lot to determine a diagnosis.

  2. Measure the cylinder compression both dry and oiled (if rises, there is a problem with a ring, if not – a valve).

  3. Check spark plug wires if possible, try to replace them to see whether the result will change.

  4. For conscience 'sake, clean throttle body and idle air control, this procedure will never be superfluous.

  5. The cold start misfire is often associated with malfunction of Mass Airflow Sensor (MAF), so firstly check this part.

  6. The variant when the banal air leak between the head and intake manifold plays a key role in misfire phenomena.

  7. Modern vehicles with fuel injection often suffer from poor fuel quality, but it is not a secret, it is not at the highest level, that’s why the actual washing of nozzles and change of a gas station can be quite righteous.

Diesel Engine Misfire

Diesel cold engine misfire problem is as common as for gasoline engines, but the search range decreases to several reasons.

Firstly, it can be airing.

Secondly, the problem is in the glow plug.

Third, there is a cold nozzle malfunction.

Here are three basic and most common problems. But there also can be a problem in the valve clearances, inappropriate marks of T-belts and fuel pump belts.

However, before checking and changing everything, remember that modern engines do not tolerate «blind diagnosis», there are too many similar symptoms for different faults.

Changing every device that you are advised can be useless. That’s why if possible, make computer diagnostics and draw conclusions about the causes of failure on basis of the obtained results.

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