Stepper motor: performance, model and price

A stepper motor, also called a solenoid valve, is used to regulate the idle speed of your car's engine. Located next to the air and fuel injection system, the stepper motor is in the form of a solenoid valve controlled by the injection device. In this article, you will find all the information you need to know about this part: how it works, the symptoms of wear and the cost of replacing it in the workshop!

🚘 How does a stepper motor work?

Known asidle drive, the stepper motor will regulate the flow of air to be injected into the engine when the car is idling. This solenoid valve consists of two parts: servo amplifier and nozzle holder.

He plays a key role in ensuring air regulation injected into the engine in several different situations: when the engine is idling, when using the air conditioner, or even when changing gears. Really, required air supply and fuel will fluctuate depending on the needs of the engine... It is with this in mind that the stepper motor comes into play because this allows for more air flow when opening times injectors increases.

Specifically, a stepper motor is built with a solenoid valve and multiple windings that are connected to calculating car. The latter also allows control of the windings. His work is based on principle of electromagnetism where the core makes rotations or steps, which explains its name. Thus, these steps increase or decrease the air supply when the engine is idling.

⚙️Bipolar vs. Unipolar Stepper Motor: What are the Differences?

The bipolar or unipolar nature of a stepper motor depends mainly on the winding of the vehicle motor. Thus, bipolar and unipolar stepper motors have several differences, namely:

• Engine design : Connections and windings differ from bipolar to unipolar. It should be noted that the number of windings and connections also varies from one model to another;
• Current polarity : A unipolar motor has only one current or voltage polarity, while a bipolar motor has two polarities. This means that in the latter case, the direction of the voltage in the coil can change, while for a unipolar motor, the current has only one direction;
• Motor coils : in a unipolar motor, the coils are connected in a special way to transfer power from the end of one coil to the beginning of the other. In a bipolar motor, the connections are different because the current can flow in both directions;
• Torque force : the bipolar motor provides more torque than the unipolar motor. This is due to the fact that the design of the connections is more complex and therefore allows more power to be guaranteed.

⚠️ What are the symptoms of HS stepper motor?

A stepper motor will wear out over time, but it will not wear out. Several symptoms can indicate wear and tear, they will look like this:

1. Lack of engine stability at idle : it will vibrate strongly and be difficult to stabilize;
2. Engine stalls frequently : the air supply is insufficient, which causes problems in the operation of the engine;
3. Stepper motor is dirty : The presence of limescale or impurities will interfere with the correct functioning of this element. In particular, there are short circuits in the coil.
4. Le engine warning light on : This warning light is very important, it is responsible for informing the motorist of any abnormalities associated with the operation of the engine.

Your car's engine is made up of many parts, so you need to seek professional help to diagnose a problem with a stepper motor. Indeed, some symptoms are characteristic of other failures, such as injector clogged.

💸 How much does it cost to replace a stepper motor?

Replacing a stepper motor is inexpensive, unlike the idle drive model with a modulating motor. On average, it takes from 15 € and 30 € for the purchase of a new part. In addition, you need to consider the cost of labor required to implement the change. Typically, full intervention will cost you between 50 € and 350 € depending on your car model and the hourly rate charged by the institution.

A stepper motor is not a wearing part, it should last the life of your machine. To avoid any risk of malfunction associated with this, it will be necessary to regularly service your vehicle, in particular by removing the carbon present in the engine system!