Characteristics and malfunctions of the D-245.7E3 / D-245.9E3 engine of the PAZ 32053-07 bus

General Information about D-245.7E3 and D-245.9E3 Diesel Engines

Diesel model D-245.7E3 is installed on PAZ-32053-07 buses. Diesel model D-245.9E3 is installed on PAZ-4234 and PAZ-32053-07 buses.

Longitudinal section of the diesel engine with all main components labeled
Longitudinal section of the engine:
1 — piston cooling nozzle; 2 — water pump; 3 — piston pin; 4 — connecting rod; 5 — cap; 6 — piston; 7 — cylinder liner;
8 — cylinder head cover; 9 — cylinder head; 10 — cylinder block; 11 — flywheel; 12 — crankshaft counterweight; 13 — crankshaft;
14 — oil receiver; 15 — oil pump

Diesel engines use a Common Rail fuel system with electronic injection control, which ensures environmental performance corresponding to the Euro-3 level by optimizing the work process.

The engine includes: cylinder block with suspension; crank and gas distribution mechanisms; lubrication, power and cooling systems; charging and starting devices, drives of electrical equipment and units.

Diesel Technical Characteristics

Engine model: D-245.7E3 or D-245.9E3
Type: Diesel, four-stroke, with turbocharging and charge air cooling.
Method of mixture formation: Direct fuel injection
Number and arrangement of cylinders: 4, in-line, vertical
Cylinder displacement: 4.75 L
Cylinder operating order: 1-3-4-2
Direction of rotation of the crankshaft: right (clockwise)
Compression ratio: 17
Rated rotation speed: 2400 min⁻¹
Minimum idle speed: 750-800 min⁻¹
Maximum idle speed (no more than): 2650 min⁻¹
Ventilation system: Open
Lubrication system: Combined (under pressure from the oil pump and splash)
Cooling in the lubrication system: Liquid-oil heat exchanger
Oil filter: Full flow, non-separable, mod. FM 009-1012005 or M5101
High pressure fuel pump: CP3.3 (BOSCH, Germany)
Electronic diesel control unit: EDC7UC31 (BOSCH, Germany)
Injector: CRIN2 (BOSCH, Germany)
Coarse fuel filter: Preline PL 270 (MANN-HUMMEL GMBH, Germany)
Fine fuel filter: Mann & Hummel WDK962/12 or WDK962/14 (Germany)
Air filter: Air cleaner with paper filter elements
Supercharging system: With adjustable boost pressure and air-to-air charge air cooler
Turbocompressor: C14 (Turbo company), C15 (Turbo company) or S200G (Schwitzer company, Germany)
Diesel cooling system: Liquid, closed type, with forced circulation of liquid, thermostat and expansion tank
Engine starting aids: Glow plugs and liquid heater

Parameter D-245.7E3 D-245.9E3
Cylinder diameter/piston stroke, mm110125
Rated power, net, kW85.095.0
Maximum torque, net, N·m422456
Rotation speed at maximum torque, min⁻¹1000–15001500–1600

Possible Engine Malfunctions and Elimination Methods

Problems Starting the Engine

Engine does not start:

  • Check that there is fuel in the fuel tank — fill the tank.
  • Check the functionality of the starter and its control circuits — make necessary repairs.
  • Check the low pressure circuit (connections, leaks, filter, water, air) — make repairs, replace filter, remove water and air.
  • Check for leaks in the high pressure circuit — make necessary repairs.
  • Check the electrical circuit (battery charging, fuses, ground wire) — charge battery, replace fuses, replace ground wire.
  • Check diesel parameters using diagnostic tool "KTS - Bosch" — follow diagnostic program instructions (repair in specialized workshop).
  • Check the intake system (leaks/air leaks, air filter, manifold clogging) — make repairs, replace filter, clean manifold.
  • Check the reliability of glow plugs — replace glow plugs or control unit.
  • Check the condition of the wiring harness (open or short circuit) — make necessary repairs.
  • Check the compression level in cylinders — make necessary repairs.
  • Check injectors using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check high pressure pump using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the reliability of control unit connectors — secure connectors.

Engine is difficult to start or starts and then stops:

  • Check that there is fuel in the fuel tank — fill the tank.
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check for leaks in the high pressure circuit — make necessary repairs.
  • Check the electrical circuit — charge battery, replace fuses, replace ground wire.
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check glow plugs — replace.
  • Check wiring harness — make necessary repairs.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check compression level — make necessary repairs.
  • Check control unit connectors — secure.

Hot engine is difficult to start:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check compression level — make necessary repairs.
  • Check wiring harness — make necessary repairs.
  • Check control unit connectors — secure.

Unstable Engine Idling

Unstable idle speed:

  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check wiring harness — make necessary repairs.
  • Check for leaks in the high pressure circuit — make necessary repairs.
  • Check compression level — make necessary repairs.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check high pressure pump — follow instructions (repair in specialized workshop).

Idle speed too high or too low:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the electrical circuit — make repairs, replace wire.
  • Check that the clutch is adjusted correctly — make necessary repairs.
  • Check wiring harness — make necessary repairs.
  • Check control unit connectors — secure.

Engine Behavior When Vehicle is Moving

Unstable engine operation during acceleration/deceleration:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system (leaks, filter, clogging) — make repairs, replace filter, clean manifold.
  • Check wiring harness — make necessary repairs.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check control unit connectors — secure.

Dips during acceleration and when engaging the clutch:

  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Determine the health status of the turbocharger.
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check compression level — make necessary repairs.
  • Check for leaks in the high pressure circuit — make necessary repairs.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check control unit connectors — secure.

Engine stopping:

  • Check for fuel in the fuel tank — fill the tank.
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check for leaks in the high pressure circuit — make necessary repairs.
  • Check the electrical circuit — make repairs, replace wire.
  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check wiring harness — make necessary repairs.
  • Check high pressure pump — follow instructions (repair in specialized workshop).
  • Check control unit connectors — secure.

Engine runs intermittently:

  • Check for fuel in the fuel tank — fill the tank.
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check wiring harness — make necessary repairs.
  • Check compression level — make necessary repairs.
  • Check clearances in the valve drive — adjust.
  • Check high pressure pump — follow instructions (repair in specialized workshop).
  • Check control unit connectors — secure.

Insufficient power:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check oil level — top up.
  • Determine the health status of the turbocharger.
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check compression level — make necessary repairs.
  • Check clearances in the valve drive — adjust.

Excessive power:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Monitor oil consumption (engine overload) — if increased, make repairs.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check control unit connectors — secure.

Excessive fuel consumption:

  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check fuel temperature sensor for leaks — replace.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check for leaks in the high pressure circuit — make necessary repairs.
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check oil level — top up.
  • Determine the health status of the turbocharger.
  • Check compression level — make necessary repairs.
  • Check control unit connectors — secure.

Extra-high engine speeds when releasing the pedal or changing gear:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check wiring harness — make necessary repairs.
  • Check that the clutch is adjusted correctly — make necessary repairs.
  • Determine the health status of the turbocharger.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check control unit connectors — secure.

Engine stalls when accelerating:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check that the clutch is adjusted correctly — make necessary repairs.
  • Check wiring harness — make necessary repairs.
  • Check control unit connectors — secure.

Engine does not stop:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).

Noise, Smell or Smoke

Knocking or noise in the engine:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check compression level — make necessary repairs.
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check injectors — follow instructions (repair in specialized workshop).

Intermittent noise:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check wiring harness — make necessary repairs.
  • Check control unit connectors — secure.

Various mechanical noises:

  • Ensure injectors are not rattling — make repairs.
  • Check fuel pipe holders — make necessary repairs.
  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check that the clutch is adjusted correctly — make necessary repairs.
  • Determine the health status of the turbocharger.
  • Check clearances in the valve drive — adjust.

Exhaust gas smell:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Monitor oil consumption — if increased, make repairs.
  • Determine the health status of the turbocharger.
  • Check oil level — top up.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check control unit connectors — secure.

Diesel fuel smell:

  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check fuel temperature sensor for leaks — replace.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check for leaks in the high pressure circuit — make necessary repairs.

Blue, white or black smoke:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check oil level — top up.
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Monitor oil consumption — if increased, make repairs.
  • Check compression level — make necessary repairs.
  • Check injectors — follow instructions (repair in specialized workshop).

Blue, white or black smoke when accelerating:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Check the intake system — make repairs, replace filter, clean manifold.
  • Check the low pressure circuit — make repairs, replace filter, remove water and air.
  • Check oil level — top up.
  • Determine the health status of the turbocharger.
  • Monitor oil consumption — if increased, make repairs.
  • Check compression level — make necessary repairs.
  • Check for leaks in the high pressure circuit — make necessary repairs.
  • Check wiring harness — make necessary repairs.
  • Check injectors — follow instructions (repair in specialized workshop).
  • Check control unit connectors — secure.

Engine Overheating

Diesel overheats:

  • Insufficient amount of coolant — top up.
  • Outside of radiator is dirty — clean.
  • Thermostat valve does not open completely — replace thermostat.
  • Insufficient fan belt tension — tighten.
  • Oiling of fan drive belt and pulleys — remove belt, remove oil.

Oil Pressure

Oil pressure on heated diesel is below permissible level:

  • Check diesel parameters using diagnostic tool — follow instructions (repair in specialized workshop).
  • Faulty sensor or pressure indicator — replace.
  • Leakage in oil pipe connections — identify and restore.
  • Faulty oil pump — identify and fix.
  • Oil level below permissible level — top up.
  • Limit wear in joints (crankshaft journals — bearings) — fix.
  • Safety valve stuck in oil filter housing — wash, adjust pressure.
  • Oil filter clogged — replace.

Turbocharger

Turbocharger rotor does not rotate (characteristic high-pitched sound absent):

  • Foreign objects present — remove pipes, remove objects.
  • Rotor jamming in bearing — replace turbocharger.

Increased oil emissions, oil seal leakage — remove turbocharger, send for repair.

Starter

Starter does not turn the crankshaft or rotates very slowly:

  • Loose battery terminals or oxidation — clean, tighten.
  • Battery discharged — charge or replace.
  • Commutator and brushes dirty — clean.
  • Poor brush contact, brush wear — clean, replace.
  • Starter relay contacts burned — clean, turn contact bolts, flip plate.
  • Starter drive faulty — replace.

After starting, starter remains engaged: — contact plate welded — perform repairs or replace relay.

Starter armature rotates at high speed without turning the crankshaft — flywheel ring teeth broken — replace ring; drive faulty — replace.

Starter relay works intermittently: — relay holding winding broken — replace; battery discharged — charge.

Drive gear does not engage with flywheel ring — end wear of ring — replace; gear jamming — clean, lubricate; gear tooth end wear — replace drive.

Generator

Voltmeter does not show charging:

  • Breakage of positive terminal or short circuit — repair in specialized workshop.
  • Open circuit of excitation coil — repair in specialized workshop.
  • Short circuit to housing of one stator phase — replace stator (repair in specialized workshop).
  • Short circuit or diode breakdown — replace rectifier (repair in specialized workshop).
  • Voltage regulator faulty — replace (repair in specialized workshop).
  • Poor brush contact, stuck or worn brushes — clean, replace.

Generator does not deliver full power: — wire break, stator phase break, interturn short circuit, diode fault — repair in specialized workshop.

Battery systematically overcharged — voltage regulator faulty, terminal "Ш" short circuit — repair in specialized workshop.

Generator noise — belt slipping or excessive tension — adjust.