Suzuki VLR1800 Service Manual page 80

1A-11 Engine General Information and Diagnosis:
Condition
Engine lacks power
(Defective control circuit
or sensor)
Engine overheats
(Defective engine internal
parts)
Engine overheats (Lean
fuel/air mixture)
Engine overheats (Other
factors)
Dirty or heavy exhaust
smoke
Possible cause
Low fuel pressure.
Defective TP sensor.
Defective IAT sensor.
Defective CKP sensor.
Defective GP sensor.
Defective IAP sensors.
TP sensor out of adjustment.
Defective STP sensor and/or STVA.
Defective EXCVA or EXCV.
Heavy carbon deposit on piston crown. Clean.
Not enough oil in the engine.
Defective oil pump or clogged oil circuit. Replace or clean.
Sucking air from intake pipes.
Use of incorrect engine oil.
Defective cooling system.
Defective EXCVA or EXCV.
Short-circuited IAP sensors/lead wires. Repair or replace.
Short-circuited IAT sensor/lead wire.
Sucking air from intake pipe joint.
Defective fuel injectors.
Defective ECT sensor.
Ignition timing is too advanced due to
defective timing advance system (ECT
sensor, GP sensor, CKP sensor or
ECM).
ISC valve incorrect learning.
Too much engine oil.
Worn piston rings or cylinders.
Worn valve guides.
Scored or scuffed cylinder walls.
Worn valve stems.
Defective stem seal.
Worn oil ring side rails.
Correction / Reference Item
Repair or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Adjust.
Replace.
Replace.
Add oil.
Retighten or replace.
Change.
See radiator section.
Replace.
Repair or replace.
Repair or replace.
Replace.
Replace.
Replace.
Reset learned value.
Check with inspection window, drain out
excess oil.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.