Mazda BP-4W, BP-ZE 1.8L Factory Workshop Manual

The official factory manual for the Mazda BP-4W and BP-ZE 1.8 liter engines. Includes detailed instructions for maintenance, diagnostics and repair. Contains wiring diagrams, specifications, assembly and disassembly procedures, and troubleshooting tips. Ideal for professionals and enthusiasts.

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Engine type: In-line 4-cylinder, petrol

Capacity: 1.8 liters (1839 cm³)

Valve mechanism: DOHC, 16 valves

Cylinder block: Cast iron

Cylinder head: Aluminum

BP-ZE 128–146 hp (Natural version)

BP-4W 140–155 hp Mazda MX-5 NB

BP-T 178–210 hp (Turbocharged version)

Despite their reliability and durability, Mazda BP series engines (BP-ZE, BP-4W and BP-T) are not without their characteristic shortcomings. Here are the main problems that owners encounter:

• 1.Timing system problems

Symptoms: Timing chain or belt noise, uneven engine operation.

Cause: Timing belt, rollers or tensioners are worn (typical for high mileage).

Solution: Regular timing belt replacement every 60-90 thousand km.

• 2. High oil consumption

Symptoms: Excessive oil consumption, smoke from the exhaust pipe.

Cause: Worn valve stem seals, piston rings or damaged cylinders.

Solution: Replace valve stem seals, overhaul the engine if necessary.

• 3. Sensor problems

Symptoms: Errors on the instrument panel, engine misfires.

Cause: Faulty crankshaft position (CKP) or camshaft position (CMP) sensors.

Solution: Diagnose the system, replace faulty sensors.

• 4. Engine overheating

Symptoms: High engine temperature, coolant leak.

Cause: Clogged radiator, faulty thermostat or coolant pump.

Solution: Flush the cooling system, replace faulty components.

• 5. Oil leak

Symptoms: Oil stains under the car, low oil level.

Cause: Worn valve cover gasket, front or rear crankshaft oil seal.

Solution: Replace gaskets and oil seals.

• 6. Uneven idling

Symptoms: RPM fluctuations, engine stalls.

Cause: Clogged idle air control (IAC) valve, dirty throttle valve.

Solution: Clean the IAC valve and throttle valve.

• 7. Corroded and aged wiring

Symptoms: Misfiring, no spark.

Cause: Corroded connectors or damaged high-voltage wires.

Solution: Check and replace wiring, clean connectors.

• 8. Fuel system problems

Symptoms: Difficulty starting, loss of power.

Cause: Clogged injectors or fuel pump failure.

Solution: Clean injectors, replace filter or pump.

• 9. Antifreeze leak

Symptoms: Low coolant level, antifreeze smell in the cabin.

Cause: Worn cylinder head gasket or radiator.

Solution: Replace cylinder head gasket, repair cooling system.