The EGR valve in the IDE engine was present until 2001, and later, due to high failure rates and significant contamination of the intake system, its use was abandoned. The EGR valve is an extended with a potentiometer measuring the degree of opening, a standard EGR valve with increased flow. The problem appears after a short mileage, as the increased exhaust gas flow strongly contaminates the valve head, making it difficult to move. However, each trim of the valve results in an immediate reading error of the valve opening degree. In extreme cases, it may end with an emergency engine shutdown. Fortunately, the valve can be removed, cleaned, and driven. You can also plug it so that it does not get dirty, but in this particular engine it is not the best solution, because the presence of exhaust gases in the mixture not only impoverishes the mixture but also lowers the combustion temperature. When there is no exhaust gas, additional air is taken in place of the inert gas and the computer, based on the readings from the lambda probe, artificially increases the fuel dose. In addition, the suction resistance increases, which also reduces the efficiency of the unit. Nevertheless, most users blind the EGR valve inlet for fear of an unpleasant surprise while driving. The only difference in use is a slightly sharper response to the gas pedal in the 1700-3800 rpm range and perhaps a bit less economy. However, according to the computer data from the 350 km route, the difference was minimal 6.4 l / 100 km with the blind valve and 6.2 with the working one. (smooth driving at a speed of about 100-110 km / h), i.e. within the error limits.

The EGR valve only actuates under certain conditions:

  • the air temperature is greater than 10 ° C, the engine temperature is greater than 70 ° C
  • negative pressure in the intake manifold is between 300-650 mbar
  • engine speed is between 1700-3800 rpm
  • the engine load is within the given limits

The EGR valve is disabled in the event of incorrect data reading from:

  • engine temperature sensor
  • air temperature sensor
  • pressure sensor
  • speed sensor
  • EGR valve

Electrical connection

1 - potentiometer output
2 - mass of the potentiometer
3 - potentiometer power supply
4 - valve mass
6 - valve power supply
potentiometer path resistance approx. 5 kΩ
potentiometer output resistance 150Ω-5kΩ
valve coil resistance 6 Ω

Dissasembly and assembly EGR

It is quite simple, but it is best to perform it on a cold engine as it is possible to get burned by hot engine parts.
Disconnect the battery, then remove the plug from the valve. Then unscrew the two mounting bolts to the manifold. Then use pliers to remove the clamp connecting the exhaust gas inlet to the valve. The valve goes up without any problems. To clean the valve, first soak its lower part with a penetrating agent. Then move the valve stem while flushing with a penetrating agent. After some time, the valve starts to work lightly. The valve is quite a durable element and, apart from typical dirt, the potentiometer is rarely damaged. In order to check the correct operation, the valve can be connected to 12V between pins 4 and 6.
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