Isuzu 1999 RODEO Workshop Manual page 989

6E1–362 RODEO X22SE 2.2L ENGINE DRIVEABILITY AND EMISSION
DETONATION/SPARK KNOCK SYMPTOM
DEFINITION:
A mild to severe ping, usually worse under acceleration.
The engine makes sharp metallic knocks that change
with throttle opening.
Step
1 Was the On–Board Diagnostic (OBD) System Check
performed?
2 1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
3 Was a visual/physical check performed?
4 1. If Tech 2 readings are normal and there are no
engine mechanical faults, fill the fuel tank with a
known quality gasoline that has a minimum octane
rating of 87. Refer to Typical Scan Values.
2. Re–evaluate the vehicle performance.
Is detonation present?
5 1. Check for obvious overheating problems:
f
Low engine coolant.
f
Restricted air flow to radiator, or restricted
water flow through radiator.
f
Incorrect coolant solution. It should be a 50/50
mix of approved antifreeze/water.
f
Incorrect EGR operation. Refer to DTC
P0401.
2. If a problem is found, repair as necessary.
Was a problem found?
6 Check fuel pressure. Refer to Fuel System Pressure
Test.
Was a problem found?
7 Check items that can cause an engine to run lean.
Refer to Diagnostic Aids in DTC P0171.
Was a problem found?
8 Check spark plugs for proper heat range. Refer to
General Information.
Were incorrect spark plugs installed?
9 1. Remove excessive carbon buildup with a top engine
cleaner. Refer to instructions on the top engine
cleaner can.
2. Re–evaluate vehicle performance.
Is detonation still present?
Action Value(s) Yes
— Go to Step 2
— Verify repair
— Go to Step 4
— Go to Step 5
— Verify repair
— Verify repair
— Verify repair
— Verify repair
Go to Step 10
—
No
Go to OBD
System
Check
Go to Step 3
Go to Visual /
Physical
Check
Verify repair
Go to Step 6
Go to Step 7
Go to Step 8
Go to Step 9
Verify repair