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Airflow mac crack crack#In other cases, a crack will form in the accordion-style pleats of the duct that opens in response to engine torque. In most cases, the clamps holding the duct have been left loose following a previous service. To illustrate, a no-code stalling complaint can be caused by a leak in the air duct tube connecting the airflow sensor to the throttle body. Airflow mac crack software#Depending upon the sensor’s design and the software written into the PCM, a defective airflow sensor may or may not set a diagnostic trouble code (DTC) in the PCM’s diagnostic memory. See Photo 1.īecause the air filter and air filter housing are designed to reduce airflow turbulence, modifying the intake air assembly always introduces the possibility that airflow sensor performance might be impaired.īecause hot-wire sensors are the most common, we’ll concentrate on summarizing conditions and pattern failures that affect hot-wire performance. Airflow mac crack install#In light of the above information, whether to install an oil-impregnated air filter or not amounts to a judgment call on the part of the vehicle owner, technician and shop management.Īnother aspect of air filter performance is that air turbulence caused by modifying the intake air system can affect the accuracy of any hot-wire sensor. On the other side of the issue, manufacturers of oil-impregnated filters claim to have documented research showing that their brand-name oil won’t affect the accuracy of a hot-wire airflow sensor. ![]() Airflow mac crack professional#Many professional technicians feel that this accumulation of oil will seriously degrade the sensor’s performance. In other cases, less experienced techs over-oil the filter media, which causes oil to enter the air stream and accumulate on the airflow sensing elements. Some automakers will automatically void a new-vehicle warranty when one of these systems is installed. More controversial are the use of oil-impregnated performance filters on air intake systems. If the air filter box is damaged, new assemblies are available from dealership parts and, in some applications, from aftermarket sources. In other cases, damaged seals on the air box allow air-borne dirt to flow around the air filter into the airflow sensor. Other cheaply-made air filters tend to leak dirt at perforations in their pleats and allow dirt and other debris to accumulate on the hot wire. These particles insulate the hot wire from the cooling effects of the air stream, which causes the airflow sensor to underestimate airflow at highway speeds. ![]() Although it’s relatively rare, some cheaply made air filters shed paper particles into the air stream, which accumulate on the hot wire. Most airflow sensors fail because inferior replacement air filters are installed or because the integrity of the air filter box is compromised during service. The hot-wire sensor may also contain a separate intake air temperature sensor that provides an independent air temperature input to the PCM. The PCM then calculates an air-to-fuel ratio that corresponds with engine speed and load. ![]() These changes of current flow in the hot wire are translated by the MAF sensor electronics into a variable voltage or frequency signal that indicates to the PCM the amount of air flowing into the engine. In a Toyota application, for example, the temperature of the hot wire is maintained at a constant value in relation to the temperature indicated by the thermistor in the sensor’s electronic circuit. The hot-wire sensor also contains a thermistor that measures the temperature of the incoming air. ![]() Hot-wire sensors, which are the most commonly used in current automotive applications, operate on the principle of electrical resistance in a heated wire changing in response to the cooling effects of air flowing past the wire. These variations in reflected light are translated into a frequency indicating the amount of airflow into the engine. Changes in the vortex of the airflow as it passes over the mirror causes variations in light reflected from the mirror. Airflow is measured by directing the airflow against a metal foil mirror that’s illuminated by a light-emitting diode (LED). Although Karmen Vortex airflow sensors are relatively uncommon, it’s important to recognize that they measure airflow by creating a swirling effect or vortex in the airflow stream. Some import vehicles use a Karmen Vortex airflow meter to supply an airflow input to the engine management system. ![]()
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