← AD
Autopapyrus · Nissan AD 1.2.2 YD22DD (2002)
https://autopapyrus.com/guides/nissan/ad/injection-pump-replacement-bosch-vp44/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Nissan AD 1.2.2 YD22DD (2002): Injection Pump Replacement (Bosch VP44)

The YD22DD is equipped with an electronic Bosch VP44 distributor pump and the NEO-Di system, with a chain-driven timing system. Replacing the pump requires exact alignment to the timing marks and a completely dirt-free fuel system. The exact procedure for this model is not documented in publicly available service materials, so what follows is the general principle. Check all torque values against the manufacturer's specifications.

Difficulty: Hard Time: 4-8 hours Steps: 13 Tools: Socket and wrench set (8-19 mm), Torx and E-type sockets, torque wrench, gear or pulley puller for the pump drive, flare-nut (split) wrench for high-pressure fuel lines, caps/plugs for open fittings, clean container, shop rags, pump drive gear or chain locking tool (homemade or special tool), diagnostic scan tool, work light and cleaner for the pump area.

Part

  • 🔩 Bosch VP44 injection pump for YD22DD (electronically controlled high-pressure distributor pump). Get the pump made specifically for this engine, as it is matched to the control unit. Also needed: pump O-rings and gasket, fuel filter, pump tappet or drive (inspect, replace if worn), seals as needed

Step by step

13 steps
  1. Park the vehicle on a level surface and disconnect the negative battery terminal. Thoroughly wash and blow dry the pump, fuel lines and fittings: dirt in the system will destroy the new pump.
  2. Remove the air filter and its ducts, and the air filter housing if necessary (the job can be done without removing the housing, but it is easier with it removed). Remove the engine undercover, and if necessary the decorative cover and any vacuum hoses in the way.
  3. Turn the crankshaft in its normal direction of rotation and set the No. 1 cylinder piston to TDC using the marks. Take a photo of the position of the marks on the pump gear or pulley and on the housing. Do not turn the crankshaft or the gear after the pump is removed.
  4. Relieve the residual pressure, disconnect the fuel supply and return lines, and plug the fittings and lines with caps. Collect any fuel that drains out.
  5. Disconnect the pump's electrical connector (on the VP44 the pump control unit is built into the pump itself), and if present, the sensors and the cable.
  6. Remove the high-pressure fuel lines between the pump and the injectors (using a flare-nut wrench, one at a time). Cap the injectors and the pump outlet fittings.
  7. Lock the pump drive gear (it is connected to the chain) so the timing position is not lost: use a special locking tool or a homemade one. Remove the pump gear nut and take the gear off with a puller, without hitting the shaft.
  8. Remove the pump mounting fasteners (nuts or bolts on the flange and bracket) and carefully remove the pump. Inspect the pump tappet or drive and replace it if worn.
  9. Install the new pump with new seals. Align the marks on the gear, flange and housing as they were on the old pump. Tighten the fasteners to the manufacturer's specified torque, not by feel.
  10. Install the pump gear and tighten the nut to specification. Make sure the timing marks and the pump marks still line up (check by turning the crankshaft two full revolutions and comparing the marks).
  11. Connect the fuel lines, reinstall the high-pressure lines (tighten to specification) and connect the connector. Fill the fuel filter (new one installed) with fuel and bleed the system with the hand primer pump all the way, if equipped.
  12. Reconnect the battery. After pump replacement, the VP44 control unit may require pairing, adaptation or code reading: if the engine does not start or there are fault codes, run a diagnostic with a scan tool. If the pump is not from the same engine and the engine does not start, the pairing can only be done with shop equipment.
  13. Start the engine (it may need extended cranking, no more than 10-15 seconds at a time), and check for fuel leaks and fault codes. Take a test drive and check performance and that there is no soot or smoke.

Common mistakes and warnings

  • This is a difficult job: incorrect pump timing relative to the engine timing results in hard starting, misfires and rough running, and can damage the engine. Working on the high-pressure system is dangerous: do not disconnect lines with the engine running and do not put your hands near leaks. If you have no experience with chain drives and electronic pumps, have the replacement done by a repair shop. The VP44 pump is sensitive to bad fuel and air in the system, so always replace the fuel filter after replacement.