2
、
the bushing of fuel pump and the armature locking
3
、
The abrasion of component of the oil face sensor
Notice for Maintenance
：
1
、
The electric fuel pump has different flow according to the demand of the engine. The fuel pump with same
shape and which can fit well will not be the right one. The spare part number should be the same as the original
when maintaining, wrong one shall not be allowed.
2
、
Do not operate the fuel pump in dry state for protecting the fuel pump from being damaged accidentally.
3
、
When it is necessary to change the fuel pump, please pay attention to the clean of uel tank and the pipeline
and the replacement of fuel filter.
Brief Measurement Method:
1
、
(Discharge the tie-in) Put the digital multimeter to ohm gear and the two pens connect with two stitiches of
fuel pump separately, measure internal resistance, if the internal resistance not zero or infinite , namely its in a
short circuit or turnoff state.
2
、
(
Contact tie-in) Contact the fuel pressure meter to the inlet pipe, start the engine to check if the fuel pump
works, if not, check the stitch “+”to see if there is voltage, or check the if the fuel pump relay is good; if the fuel
pump runs, check the fuel pressure to see if it is around 260kPa at idle speed; pull out the vacuum pipe of fuel
pressure adjustor and check if the fuel pressure is around 300kPa.
Injector
1. Brief Figure and Stitch
Stitch: every injector has two stitches, and the one beside the case marked “+” will contact the No 87 stitch of
main relay output end and the other one will contact No 26
、
6
、
7
、
47 stitch separately.
2. Working Principle
The ECU sends out electrical pulse to the coil of injector forming the magnetic field force, when the force rises
to overcome the composite force of pressure of the return spring, gravity of needle valve and friction force, the
needle valve arises, and the fuel injection starts. When the injection pulse closes, the pressure of the return spring
will make the needle valve close. Cause pressure difference between diameter of spray hole, fuel pressure and
pressure of intake manifold is invariableness. So fuel spout capacity only rest with fuel spout pulse width.(namely
the electrify time of coil).
Electromagnetic Fuel Injector
Circuit Diagram of Electromagnetic Fuel injector
