Why do the revs on the Renault Duster float

Renault Duster is a crossover that can be seen on every corner. These machines are loved for their cheapness and maintainability. Renault Duster engines are very reliable and nurture up to 400 thousand kilometers, but they are not devoid of "childhood illnesses". One of these is the problem of floating engine speed. Let's see what could be the cause and how to fix it.

Typical childhood illnesses

First, let's look at the typical problems that the owners faced almost in the first year of owning a car. If the engine speed is floating on Renault Duster, it may be:

  • "Curve" ECU firmware. Applies to gasoline engines F4R and K4M with a timing belt. The car did not start well when cold, and the idle speed swam for the first 2-3 minutes. The solution is to install new software. Your dealer will do this free of charge under warranty.
  • Intake manifold gasket. For this reason, revs often float on Renault Duster. The problem arose on pre-styling models after 30-40 thousand kilometers. Why? The material is tanned and breathable, especially in winter. On a warm engine, the rpm also jump, but not so much. The solution is to replace the gasket with a new one.
  • Throttle gasket. The revs are floating on Renault Duster for the same reasons and at the same mileage.
  • Water to the candle well of the third cylinder. And it gets there because of a leaky washer nozzle on the hood. As a result, it simply interrupts the ignition coil and the engine does not keep idling. The new nozzles passed water in the same way. Desperate Renault Duster owners simply sealed them generously with sealant. The solution may be clumsy, but it works.

Throttle valve

An electromechanical throttle is installed on a Renault Duster car. As with all cars, this damper gets dirty over time. And one day, the ECU cannot understand in what position the throttle is. The machine is difficult to start troit at idle, stalls and lifts up the revs. It would seem that the solution to the problem is obvious - disassemble, clean and go! But with Renault Duster, not everything is so simple. It is not enough just to clean the damper here. It is necessary to disassemble its electrical part and clean the arched tracks (otherwise, errors will come out at startup).

And since there is already electronics here, the throttle must be adapted. The block should see the new end positions of the damper. It is better to do this at a service station, where there are experienced craftsmen and special equipment.

Air leaks

Often, the rubber bands of the sensors dry out on Renault Duster, which is why unaccounted air gets inside and the idle speed floats. It could be:

  • mass air flow sensor;
  • absolute air pressure sensor;
  • throttle position sensor.

Moreover, the sensors themselves are fully operational. The rubber bands may appear to be in good condition, but this is a deceptive phenomenon. By replacing them, the problem goes away immediately.

Also the reason for floating speed is possible due to vacuum hoses. A common problem is the throttle heating tube dries out. Because of this little thing, the engine starts to seriously mope.

Another reason is the crankcase ventilation system. In addition to the fact that the tubes can be dirty inside, microcracks appear in them. The pressure of the crankcase gases rises - the oil squeezes into the inlet, it oozes through the oil seals and gaskets. By cleaning or replacing the ventilation system, the problem goes away.

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