The term **31112-R** is a specific part numbering convention most commonly associated with **automotive fuel system components**, specifically for Hyundai and Kia vehicles. It typically refers to the **Fuel Pump Strainer (Filter)** or the upper assembly of the fuel pump module. --- ### 1. Part Identification & Application In the automotive electronics and mechanical ecosystem, this part functions as the primary filtration stage before fuel enters the electronic pump motor. | Category | Details | | :--- | :--- | | **Common Full Part Numbers** | 31112-R1000, 31112-R9000, 31112-R2000 | | **Primary Vehicle Brands** | Hyundai, Kia | | **Associated Systems** | Electronic Fuel Injection (EFI), Fuel Delivery | | **Component Type** | Internal Fuel Filter / Strainer | --- ### 2. Electronic Context While the "31112-R" part itself is often a high-density filtration mesh or a plastic housing, it is an integral part of the **Electronic Fuel Pump Assembly**. #### Role in the Electronic Circuit: * **Pressure Regulation:** By ensuring the fuel is free of debris, it prevents the DC electric motor inside the pump from drawing excessive **amperage**. * **Motor Longevity:** Clogged filters cause the electronic pump to overheat, leading to premature failure of the copper windings. * **Sensor Protection:** It protects the **Fuel Level Sender** (a variable resistor/potentiometer) from mechanical interference caused by sediment. --- ### 3. Technical Specifications Typical characteristics of the 31112-R series filters include: * **Material:** High-grade synthetic fiber or nylon mesh. * **Housing:** Static-dissipative plastic (to prevent electrical sparking within the fuel tank). * **Filtration Rating:** Usually between 10 to 40 microns depending on the specific sub-model (e.g., R1000 vs. R9000). --- ### 4. Symptoms of Failure If this part fails or becomes clogged, the following electronic and mechanical issues occur: 1. **Electronic Throttling:** The Engine Control Unit (ECU) may detect a lean fuel mixture and adjust fuel trim percentages. 2. **Hard Starting:** The fuel system fails to prime quickly when the ignition is turned to the "ON" position. 3. **DTC Codes:** Common diagnostic trouble codes include **P0171** (System Too Lean) or **P0087** (Fuel Rail Pressure Too Low). --- ### Summary Table: Variants of 31112-R | Part Suffix | Common Vehicle Model | Note | | :--- | :--- | :--- | | **-R1000** | Hyundai Accent / Kia Rio | Standard internal tank filter | | **-R9000** | Kia Sportage / Hyundai Tucson | High-flow variant for SUVs | | **-R2000** | Hyundai Elantra | Redesigned housing for newer models |