Isuzu Rodeo UE. Service manual — part 273
6A–5
ENGINE MECHANICAL (6VD1 3.2L)
4. Engine Lacks Compression
Condition
Possible cause
Correction
Engine lacks compression
Spark plug loosely fitted or spark
plug gasket defective
Tighten to specified torque or replace
gasket
Valve timing incorrect
Adjust
Cylinder head gasket defective
Replace gasket
Valve incorrectly seated
Lap valve
Valve stem seized
Replace valve and valve guide
Valve spring weakened or broken
Replace
Cylinder or piston rings worn
Overhaul engine
Piston ring seized
Overhaul engine.
Engine Compression Test Procedure
1. Start and run the engine until the engine reaches
normal operating temperature.
2. Turn the engine off.
3. Remove all the spark plugs.
4. Remove ignition coil fuse (15A) and disable the
ignition system.
5. Remove the fuel pump relay from the relay and fuse
box.
6. Engage the starter and check that the cranking speed
is approximately 300 rpm.
7. Install cylinder compression gauge into spark plug
hole.
8. With the throttle valve opened fully, keep the starter
engaged until the compression gage needle reaches
the maximum level. Note the reading.
9. Repeat the test with each cylinder.
If the compression pressure obtained falls below the
limit, engine overhaul is necessary.
Limit; 1000 kPa (145 psi)
6A–6
ENGINE MECHANICAL (6VD1 3.2L)
Rough Engine Idling or Engine Stalling
Condition
Possible cause
Correction
Trouble in fuel injection system
Idle air control valve defective
Replace
Throttle shutting off incomplete
Correct or replace
Throttle position sensor circuit open
or shorted
Correct or replace
Fuel injector circuits open or shorted
Correct or replace
Fuel injectors damaged
Replace
Fuel pump relay defective
Replace
Mass Airflow Sensor circuit open or
poor connections
Correct or replace
Mass Airflow Sensor defective
Replace
Manifold Absolute Pressure Sensor
circuit open or poor connections
Correct or replace
Manifold Absolute Pressure Sensor
defective
Replace
Engine Coolant Temperature Sensor
circuit open or poor connections
Correct or replace
Engine Coolant Temperature Sensor
defective
Replace
Intake Air Temperature sensor circuit
open or poor connections
Correct or replace
Intake Air Temperature sensor
defective
Replace
Knock Sensor (KS) cable broken or
poor connections
Correct or replace
KS defective
Replace
KS Module circuits open or ground
Correct or replace
KS Module defective
Replace
Vehicle Speed Sensor circuit open or
shorted
Correct or replace
Vehicle Speed Sensor defective
Replace
Trouble in emission control system
Powertrain Control Module defective
Replace
Exhaust Gas Recirculation Valve
circuit open or poor connections
Correct or replace
Exhaust Gas Recirculation Valve
faulty
Replace
Canister purge valve circuit open or
poor connections
Correct or replace
Canister purge valve defective
Replace
Evaporative Emission Canister
Purge control valve defective
Replace
Trouble in ignition system
Refer to “Hard Start”
6A–7
ENGINE MECHANICAL (6VD1 3.2L)
Condition
Correction
Possible cause
Others
Engine lacks compression
Refer to “Hard Start”
Valve incorrectly seated
Lap valve
Air Cleaner Filter clogged
Replace filter element
Valve timing incorrect
Readjust
Idle air control valve broken
Replace
Fast idle solenoid defective
Replace
Positive Crankcase Ventilation valve
defective or clogged
Replace
Rough Engine Running
Condition
Possible cause
Correction
Engine misfires periodically
Ignition coil layer shorted
Replace
Spark plugs fouling
Clean or install hotter type plug
Spark plug(s) insulator nose leaking
Replace
Fuel injector(s) defective
Replace
Powertrain control module faulty
Replace
Engine knocks periodically
Spark plugs running too hot
Install colder type spark plugs
Powertrain control module faulty
Replace
Engine lacks power
Spark plugs fouled
Clean
Fuel injectors defective
Replace
Mass Airflow Sensor or Intake
Airflow Sensor circuit defective
Correct or replace
Manifold Absolute Pressure (MAP)
Sensor or Manifold Absolute
Pressure Sensor circuit defective
Correct or replace
Engine Coolant Temperature Sensor
or Engine Coolant Temperature
Sensor circuit defective
Correct or replace
Powertrain Control Module faulty
Replace
Intake Air Temperature Sensor or
Intake Air Temperature Sensor
circuit defective
Correct or replace
Throttle Position Sensor or Throttle
Position Sensor circuit defective
Correct or replace
Knock Sensor or Knock Sensor
circuits defective
Correct or replace
Knock Sensor Module or Knock
Sensor Module circuits defective
Correct or replace
6A–8
ENGINE MECHANICAL (6VD1 3.2L)
Hesitation
Condition
Possible cause
Correction
Hesitation on acceleration
Throttle Position Sensor adjustment
incorrect
Replace throttle valve assembly
Throttle Position Sensor circuit open
or shorted
Correct or replace
Excessive play in accelerator linkage
Adjust or replace
Mass Airflow Sensor circuit open or
poor connections
Correct or replace
Mass Airflow Sensor defective
Replace
Manifold Absolute Pressure (MAP)
Sensor circuit open or shorted
Correct or replace
MAP Sensor defective
Replace
Intake Air Temperature (IAT) Sensor
circuit open or poor connections
Correct or replace
Knock Sensor (KS) circuit open or
poor connections
Correct or replace
KS defective
Replace
KS Module circuits open or shorted
Correct or replace
KS Module defective
Replace
IAT Sensor defective
Replace
Hesitation at high speeds
Fuel tank strainer clogged
Clean or replace
(Fuel pressure too low)
Fuel pipe clogged
Clean or replace
Fuel filter clogged
Replace
Defective fuel pump system
Check and replace
Fuel Pressure Control Valve leaking
Replace
Hesitation at high speeds
(Fuel injector not working normally)
Power supply or ground circuit for
Multiport Fuel Injection System
shorted or open
Check and correct or replace
Fuel Injector defective
Replace
Cable of Multiport Fuel Injection
System circuit open or poor
connections
Correct or replace
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