In many cases, the bad bearings will cause a chirping noise at idle coming from the driver's side of the engine, which is another big clue. . It's updated every 1000 revolutions so it will read 0 except when your car misfires within the same 1000 revolutions of the crankshaft. If the exhaust smells rich and the O2 sensors are lean, then you probably have an ignition misfire or a stuck open injector. The bulletin applies to vehicles with above 10K Intake manifold miles. Note correct cylinder numbering: However, the most common cause of an ignition misfire is a bad ignition coil. You can check for a stuck open injector by turning the car off and watching the fuel pressure.
However, you have to be very careful interpreting O2 sensor readings when dealing with misfires because they're completely dependent upon whether combustion is occurring or not. P300 is misfire on unknown cylinder. Another important factor to consider is when the O2 sensors are going lean. A cylinder needs the proper amount of air to fuel mixture, spark, and compression to fire. The pressure your car should have at idle and under load depends on the year.
If pressure drops, continue your diagnosis. Thank you, and good luck diagnosing your Fusion!! Another tricky situation a stuck-open injector. Random misfires are a bit harder to diagnose if they are the only misfire codes on the computer. Remove any debris like leaves, wasps, dirt. Attach the pressure gauge and pressurize the cooling system. The information contained on this site is presented for informational purposes only.
If the O2 reading is normal at idle but lean under acceleration, then you probably have a fuel pressure or clogged injector problem. Always inspect coils carefully for fine cracks including the epoxy on the bottom of coil packs , which are a good sign the coil is bad see video. If you have a bad, clogged, or stuck closed injector, it may not let fuel enter the combustion chamber. Unless the light is flashing, the misfire may not be presently occurring because the problem is stored in memory for some time after the event. When P0316 appears with other codes such as , , etc, it can be a symptom of a much larger problem. Loosen the pipe clamps and remove the throttle body rubber connector. These are used to reference the specific test result you want to find.
Refer to the shop manual for other causes. Unplug the plug wires from the coil one by one. I'll update this topic if I find the exact problem. This can only happen after the crankshaft profile correction portion of the misfire monitor has completed. Misfires Basics and Intro General Information What is a misfire? Okay, on to the real task! Diagnose the problem Examine the cam cover trough. Compression test video: Another way to test compression is by performing a leak down test where compressed air is blown into the cylinder and is timed on how fast it leaks out. In some cases the rotary vane will also destroy the sensor, so you might have to replace both parts.
Vacuum Leaks A vacuum leak can cause a rough idle, misfire, and poor fuel economy. Do the math and we get that cylinder 6 is misfiring 0. The smoke test is good for finding large vacuum leaks. Seeing a very low number there under 100 is not a great cause for concern, but you will probably notice the engine running rough at times, or perhaps the misfire will get worse with time. The most common cause of P0316 are the ignition components.
This is due to the high amount of potential causes. Refer to the for other codes. The fuel injector is still injecting the correct amount of fuel, but the O2 sensor will also go lean. Another way to check for a bad fuel pump is by removing the vacuum line from the fuel pressure regulator. If you want the fix to last, you must buy the Motorcraft part.
So what the computer actually reads as true misfires will pop up here as a percent. If you find water or corrosion, examine the terminals on the electrical connector. Then disconnect the charge air temperature sensor. Most vehicles now come with iridium plugs that need changed very infrequently. I am not sure how often the data is reset or what period of time it represents. Ignition Problems Older spark plugs do not always fire correctly. First step to diagnosing a misfire is finding out what cylinders are misfiring, and when it occurs under load, idle, when you let off the gas, etc.
The list of automotive Makes at the right edge of the screen. Check the sensor for evidence of water or corrosion. That would mean the computer detects it misfiring 16. It would be wise to start looking at those codes for diagnosis. I have obviously failed this test! That's 3000 misfires in 1 million revs. To identify if it is a bad coil, swap the 5 cylinder coil with another coil, and see if the misfire follows the relocated coil. The valve was removed either in april 2002 for vulcans and may 2002 for duratec's.