Isuzu 4JA1 Workshop Manual page 8

6 – 6 TROUBLESHOOTING
3. Insufficient Power
Step
1 Was the air cleaner element condition OK? (Clogged
or not)
2 Was the intake air leakage found from intake
system?
3 Was the fuel filter element condition OK? (Clogged
or not)
4 Check the fuel injection pipes.
Does the injection pipes have obstruction or any
damage?
5 Was the water contained in the fuel?
6 Was the injection nozzle pressure or spray pattern
normal?
7 Was the compression pressure OK?
8 Was the exhaust pipe clogged?
9 Was the exhaust gas leakage found from exhaust
system?
10 Was the waste gate control actuator hose broken or
cracked?
11 Was the waste gate working completely?
12 Was turbocharger working completely?
13 Are any DTC stored?
Action Value(s) Yes
—
Go to Step 2
— Repair or
replace the
intake air
system.
—
Go to Step 4
— Repair or
replace the fuel
injection pipes.
— Replace the
fuel
—
Go to Step 7
3.0 MPa
2
(31.0 kg/cm ,
441 psi) at
200 rpm
Go to Step 8
— Repair or
replace the
exhaust pipe.
— Repair or
replace the
exhaust
system.
— Replace the
hose.
—
Go to Step 12
—
Go to Step 13
— Go to indicated
DTC
No
Clean or
replace the air
cleaner
element.
Go to Step 3
Clean or
replace the fuel
filter element.
Go to Step 5
Go to Step 6
Readjust the
injection nozzle
pressure or
replace the
nozzle.
Readjust the
valve clearance
or replace the
cylinder head
gasket or
cylinder liner or
piston or piston
ring or valve
and valve seat
Go to Step 9
Go to Step 10
Go to Step 11
Replace the
turbocharger
assembly.
Replace the
turbocharger
assembly.
Solved