Hisun HS400 Service Manual page 272

Fuel System Diagnosis
Step
1
2
3
4
5
Engine Management System
Action
Switch on Ignition
key. Fuel Pump
primes for 3
seconds when the
ignition key is ON.
Check for fuel pump
running noise for 3
seconds after
ignition key is ON.
Disconnect fuel
module coupler.
Check voltage at
the harness coupler.
Is the voltage within
10-14V ?
Connect 12V DC
power supply
(battery) to fuel
module.
Make sure that
enough fuel
available in fuel tank
to avoid fuel pump
running dry. Is the
fuel pump running
Check fuel system
pressure at Injector
inlet (with a T-joint)
while engine is
running in idle
condition.
Is the pressure
between 220-
270kPa?
Is the Pressure
below 220kPa?
Yes
If fuel pump running
noise can be heard,
go to step 4.
Go to step 3
1. Check electrical
circuit from fuel
module to ECU
2. Check ECU
Fuel Module
Operation
Normal
1. Check for leaks
from hoses hose
joints
2. Check Fuel Pump
3. Check Pressure
Regulator
7-10
No
If fuel pump running
noise can not be
heard, go to step 2.
Check the electrical
circuit from Ignition
to fuel module.
1. Check Fuel
Pump Harness
Integrity
2. Check Fuel
Pump
Go to Step 5
1. Clogged Filter
2. Kink or Blockage
in Fuel Hoses
3. Check Regulator