Toyota 4A-FE Repair Manual page 31

ENGINE MECHANICAL - Troubleshooting (4A-FE)
EM-9
AFTER FIRE, BACKFIRE
Problem Possible cause
Remedy
Page
Muffler explosion
Deceleration fuel cut system always off
Check fuel cut system
(after fire) on
DP system always off Check DP system
deceleration only
Muffler explosion Air cleaner clogged Check air cleaner
EM-15
(after fire} all the time
EFI system problem
Repair as necessary
Incorrect ignition timing
!
Reset timing
EM-20
Incorrect valve clearance Adjust valve clearance EM-16
- -
Engine backfires EFI system problem Repair as necessary
Vacuum leak
I
Check hoses and repair as
• PCV hoses
necessary
• Intake manifold
• Throttle body
• Brake booster line
Insufficient fuel flow Troubleshoot fuel system
Incorrect ignition timing Reset timing
EM-20
Incorrect valve clearance Adjust valve clearance EM-16
I
Carbon deposits in combustion Inspect cylinder head EM-68
chambers
EXCESSIVE OIL CONSUMPTION
Problem Possible cause Remedy Page
Excessive oil Oil leak
Repair as necessary
consumption
PCV line clogged
Check PCV system
Piston ring worn or damaged
Check rings
EM-130
Valve stem and guide bushing worn Check valves and guide
EM-70
bushings
Valve stem oil seal worn or damaged Check oil seals