Page 166 of 346

LM-4
I ENGINE MECHANICAL -* Troubleshooting
_.
TROUBLESHOOTING
Problem Possible cause I Remedy Page
Engine overheats Cooling system faulty Troubleshoot cooling system co-4
Incorrect ignition timing Reset timing EM-1 7
Engine will not crank or Starting system faulty Troubleshoot starting system ST-2
cranks slowly : .
Engine will not start/ Vacuum leaks Repair as necessary
hard to start 0 PCV hoses ”
(cranks OK) 0 (w/ EGR)
EGR valve
0 Intake manifold
0 Air intake chamber
0 Throttle body
0 ISC valve
Pulling in air between air flow meter and Repair as necessary FI-96, 93
throttle body
Ignition problems Perform spark test IG-5, 12
0 Ignition coil
0 Igniter
0 (7M-GE)
Distributor
(7M-GTE)
Cam position sensor
High-tension cord disconnected or broken Inspect cord IG-6, 13
No fuel supply to injector Troubleshoot EFI system FI-I 2
l No fuel in tank
0 Fuel pump not working
l Fuel filter clogged
0 Fuel line clogged or leaking
EFI system problems Repair as necessary
ISC system problem Check ISC system FL- 108
Spark plugs faulty Inspect plugs IG-7
Low compression Check compression EM-26, 2
Rough idle, stalls or Vacuum leaks Repair as necessary
misses 0 PCV hoses
0 (w/ EGR)
EGR valve
0 Intake manifold
0 Air intake chamber
0 Throttle body I
0 ISC valve
Pulling in air between sir flow meter and FI-96, 9
throttle body
Incorrect idle speed Check ISC system FI- 108
Incorrect ignition timing Reset timing EM-1 7
Ignition problems Perform spark test IG-5, 12
0 Ignition coil
0 Igniter
0 (-/M-GE)
Distributor
(-/M-GTE)
Cam position sensor
High-tension cord faulty Inspect cord IG-6, 13
EFI system problems Repair as necessary
Page 167 of 346

ENGtNE MECHANKAL - Troubleshootinn EM-S
TROUBLESHOOTING (Cont’d)
-.
Problem Possible cause Remedy Page
sough idle, stalls or Spark plugs faulty Inspect plugs IG-7
misses (cont’d)
Engine overheats Check cooling system ’ co-4
Low compression Check compression EM-26, 2;
Engine hesitates/ Vacuum leaks Repair as necessary
poor acceleration 0 PCV hoses
. (w/ EGR)
EGR valve
0 Intake manifold
’ 0 Air intake chamber .c
0 Throttle body
0 ISC valve
Pulling in air between air flow meter and Repair as necessary FI-96, 96
throttle body
Incorrect ignition timing Reset timing _ EM-1 7
Emission control system problem
(cold engine)
0 (w/ EGR)
EGR system always on Check EGR system
High-tension cord faulty Inspect cord 1G-6,
Fuel system clogged Check fuel system FI-7
Air cleaner clogged Check air cleaner EM-7
EFI system problems Repair as necessary
Spark plugs faulty Inspect plugs IG-7
Engine overheats Check cooling system co-4
Low compression Check compression EM-26, 2
Engine diesels EFI system problems Repair as necessary
(runs after ignition
switch is turned off)
Muffler explosion Deceleration fuel cut system always off Check EFI (fuel cut) system FI-128
(after fire) on
deceleration only
Muffler explosion Air cleaner clogged Check air cleaner EM-7
(after fire) all the time
EFI system problem Repair as necessary
incorrect ignition timing Reset timing EM-l.7
Engine backfires Vacuum leak Check hoses and repair as
l PCV hoses necessary
. (w/ EGR)
EGR valve c
0 Intake manifold
0 Air intake chamber
l Throttle body
0 ISC valve
Pulling in air between air flow meter and Repair as necessary Fl-96, 91
throttle body
EFI system problem Repair as necessary
Insufficient fuel flow Troubleshoot fuel system
Incorrect ignition timing Reset timing EM-l 7
Carbon deposits in combustion chambers Inspect cylinder head EM-97
Page 168 of 346

EM-6 ENGINE MECHANICAL - Troubleshooting
Problem
:- Excessive oil
consumption
Poor fuel economy
Unpleasant odor -.
TROUBLESHOOTING (Cont’d) ._
Possible cause
Oil leak
PCV line clogged
Piston rings worn or damaged
Valve stem and guide worn
Valve stem seal worn
Fuel leak
Air cleaner clogged
Incorrect ignition timing
EFI system problems
l Injector faulty
0 Deceleration fuel cut system faulty
Idle speed too high
Spark plugs faulty
EGR system always on
Low compression
Tires improperly inflated
Clutch slips
Brakes drag
Incorrect idle speed
Incorrect ignition timing
‘Vacuum leaks
0 PCV hoses
0 (w/ EGR)
EGR valve ’
0 Intake manifold
l Air intake chamber
l Throttle body
EFI system problems Remedy
Repair as necessary
Check PCV system
Check rings
Check valves
Check seals ~’
Repair as necessary
Check air cleaner
Reset timing
Repair as necessary
Check ISC system
Inspect plugs
Check EGR system
Check compression
Inflate tires to proper pressun
Troubleshoot clutch
Troubleshoot brakes
Check ISC system
Reset timing
Repair as necessary
Repair as necessary Page
EM-65
EM-37
EM-37
EM-7
EM-l 7
FI-108
IG-7
M-26, 2’
FI-108
EM-l 7
Page 183 of 346
ture adjusting screw.
6. ALTERNATIVE METHOD
NOTE:
l This method is to be used ONLY when it is absolutely
necessary to adjust the idle mixture screw or if the air
flow meter is replaced without the aid of a CO meter..
0 Thefnscribed number shows the depth of the idle mix-
ture screw positioned for presetting. ,, ,, ‘-
Example: Inscribed number depth c ”
83 - 8.3 mm (0.326
in.)
Depths over 10 mm with a decimal point are abbreviated, i.:
Example: Inscribed number depth
15 - 11.6 mm (0.463 in.)
(a) Remove the rubber plug from the air flow meter.
(b) Measure the depth of the idle mixtura, adjusting
screw with vernier calipers;
(cl Adjust the depth of idle mixture adjusting screw by
turning the screw with SST.
SST 09243-00020
(d) Reinstall the rubber plug into the hole of the idle mix-
ture adjusting screw.
Page 257 of 346

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Problem
Engine will not star-t/
hard to start
(cranks OK)
Rough idle or stalls
Engine hesitates/
poor acceleration
Muffler explosion
(after fire) all the
time
Engine backfires
Poor fuel economy
Engine overheats
TROUBLESHOOTING
Possible causes
Incorrect ignition timing
Ignition problems
0 Ignition coil
. (7M-GTE)
Igniter
. (7M-GE)
Distributor
(7M-GTE)
Cam position sensor
l High-tension cords
Ignition wiring disconnected
or broken
Spark plugs faulty
Ignition wiring faulty
Incorrect ignition timing
Ignition problems
0 Ignition coil
. I7M-GTE)
Igniter
. (7M-GE)
Distributor
(7M-GTE)
Cam position sensor
0 High-tension cords
Spark plugs faulty
Ignition wiring faulty
Incorrect ignition timing
Incorrect ignition timing
Incorrect ignition timing
Spark plugs faulty
Incorrect ignition timing
Incorrect ignition timing Remedy
Reset timing
lrkpect coil
Inspect igniter
Inspect distributor
Inspect cam position sensor
Inspect high-tension cords
Inspect wiring
Inspect plugs
Inspect wiring
Reset timing
Inspect coil
Inspect igniter
Inspect distributor
Inspect cam position sensor
Inspect high-tension cords
Inspect plugs
Inspect wiring
Reset timing
Reset timing
Reset timing
Inspect plugs
Reset timing
Reset timing =
Page-.. :
-
EM-17
IG-10 or 14
IG-17
IG-11
IG-1%
IG-6 or 13
IG-7
EM-l 7
IG-10 or 11
IG-17
IG-I 1
IG-18
IG-6 or 13
IG-7
EM-l 7
EM-1 7