Mitsubishi Montero (1991+). Manual — part 302

Incorrect ignition timing Reset ignition timing,

See TUNE-UP

Leaking valves Replace valves, See

ENGINES

Worn fuel pump diaphragm Replace diaphragm or

or piston piston

Intake Backfire Improper ignition timing Reset ignition timing,

See TUNE-UP

Faulty accelerator pump Replace accelerator

discharge pump

Improper choke operation Check choke and adjust

as required

Defective EGR valve Replace EGR valve

Fuel mixture too lean Reset air/fuel mixture,

See TUNE-UP

Choke valve initial Reset choke valve

clearance too large initial clearance

Exhaust Backfire Vacuum leak Inspect and repair

vacuum system

Faulty vacuum diverter Replace vacuum diverter

valve valve

Faulty choke operation Check choke and adjust

as required

Exhaust system leak repair exhaust system

leak

Engine Ignition timing too far Reset ignition timing,

Detonation advanced See TUNE-UP

Faulty ignition system Check ignition timing,

See TUNE-UP

Spark plugs loose or Retighten or replace

faulty plugs

Fuel delivery system Inspect lines, pump and

clogged filter for clog

EGR valve inoperative Replace EGR valve

PCV system inoperative Inspect and/or replace

hoses or valve

Vacuum leaks Check vacuum system and

repair leaks

Excessive combustion

chamber deposits Remove built-up

deposits

Leaking, sticking or Inspect and/or replace

broken valves valves

External Oil Fuel pump improperly seated Remove pump, replace

Leakage or worn gasket gasket and seat

properly

Oil pan gasket broken or Straighten pan and

pan bent replace gasket

Timing chain cover gasket Replace timing chain

broken cover gasket

Rear main oil seal worn Replace rear main oil

seal

Oil pan drain plug not Remove and reinstall

seated properly drain plug

Camshaft bearing drain Remove restriction

hole blocked

Oil pressure sending Remove and reinstall

switch leaking sending switch

Excessive Oil Worn valve stems or guides Replace stems or

Consumption guides, See ENGINES

Valve "O" ring seals Replace "O" ring seals,

damaged See ENGINES

Plugged oil drain back holes Remove restrictions

Improper PCV valve Replace PCV valve

operation

Engine oil level too high Remove excess oil

Engine oil too thin Replace thicker oil

Valve stem oil deflectors Replace oil deflectors

damaged

Incorrect piston rings Replace piston rings,

See ENGINES

Piston ring gaps not Reinstall piston rings,

staggered See ENGINES

Insufficient piston ring Replace rings, See

tension ENGINES

Piston ring grooves or oil Replace piston rings,

return slots clogged See ENGINES

Piston rings sticking in Replace piston rings,

grooves See ENGINES

Piston ring grooves Replace piston and

excessively worn rings, See ENGINES

Compression rings installed Replace compression

upside down rings correctly, See

ENGINES

Worn or scored cylinder Rebore cylinders or

walls replace block

Mismatched oil ring Replace oil ring

expander and rail expander and rail, See

ENGINES

Intake gasket dowels too Replace intake gasket

long dowels

Excessive main or connecting Replace main or

rod bearing clearance connecting rod

bearings, See ENGINES

No Oil Pressure Low oil level Add oil to proper level

Oil pressure sender or Replace sender or gauge

gauge broken

Oil pump malfunction Remove and overhaul oil

pump, See ENGINES

Oil pressure relief valve Remove and reinstall

sticking valve

Oil pump passages blocked Overhaul oil pump, See

ENGINES

Oil pickup screen or tube remove restriction

blocked

Loose oil inlet tube Tighten oil inlet tube

Loose camshaft bearings Replace camshaft

bearings, See ENGINES

Internal leakage at oil Replace block or

passages cylinder head

Low Oil Pressure Low engine oil level Add oil to proper level

Engine oil too thin Remove and replace with

thicker oil

Excessive oil pump Reduce oil pump

clearance clearance, See ENGINES

Oil pickup tube or screen Remove restrictions

blocked

Main, rod or cam bearing Replace bearing to

clearance excessive reduce clearance, See

ENGINES

High Oil Improper grade of oil Replace with proper oil

Pressure Oil pressure relief valve Eliminate binding

stuck closed

Oil pressure sender or Replace sender or gauge

gauge faulty

Noisy Main Inadequate oil supply Check oil delivery to

Bearings main bearings

Excessive main bearing Replace main bearings,

clearance See ENGINES

Excessive crankshaft end Replace crankshaft, See

play ENGINES

Loose flywheel or torque Tighten attaching bolts

converter

Loose or damaged vibration Tighten or replace

damper vibration damper

Crankshaft journals Re-grind crankshaft

out-of-round journals

Excessive belt tension Loosen belt tension

Noisy Connecting Excessive bearing clearance Replace bearing, See

Rods or missing bearing ENGINES

Crankshaft rod journal Re-grind crankshaft

out-of-round journal

Misaligned connecting rod Remove rod or cap and

or cap realign

Incorrectly tightened rod Remove and re-tighten

bolts rod bolts

Noisy Pistons Excessive piston-to-bore Install larger pistons,

and Rings clearance See ENGINES

Bore tapered or out-of-round Rebore block

Piston ring broken Replace piston rings,

See ENGINES

Piston pin loose or seized Replace piston pin, See

ENGINES

Connecting rods misaligned Realign connecting rods

Ring side clearance too Replace with larger or

loose or tight smaller rings

Carbon build-up on piston Remove carbon

Noisy Valve Worn or bent push rods Replace push rods, See

Train ENGINES

Worn rocker arms or bridged Replace push rods, See

pivots ENGINES

Dirt or chips in valve Remove lifters and

lifters remove dirt/chips

Excessive valve lifter Replace valve lifters,

leak-down See ENGINES

Valve lifter face worn Replace valve lifters,

See ENGINES

Broken or cocked valve replace or reposition

springs springs

Too much valve stem-to-guide Replace valve guides,

clearance See ENGINES

Valve bent Replace valve, See

ENGINES

Loose rocker arms Retighten rocker arms,

See ENGINES

Excessive valve seat Reface valve seats, See

run-out ENGINES

Missing valve lock Install new valve lock

Excessively worn camshaft Replace camshaft, See

lobes ENGINES

Plugged valve lifter oil Eliminate restriction

holes or replace lifter

Faulty valve lifter check Replace lifter check

ball ball, See ENGINES

Rocker arm nut installed Remove and reinstall

upside down correctly

Valve lifter incorrect for Remove and replace

engine valve lifters

Faulty push rod seat or Replace plunger or push

lifter plunger rod

Noisy Valves Improper valve lash Re-adjust valve lash,

See ENGINES

Worn or dirty valve lifters Clean and/or replace

lifters

Worn valve guides Replace valve guides,

See ENGINES

Excessive valve seat or Reface seats or valve

face run-out face

Worn camshaft lobes Replace camshaft, See

ENGINES

Loose rocker arm studs Re-tighten rocker arm

studs, See ENGINES

Bent push rods Replace push rods, See

ENGINES

Broken valve springs Replace valve springs,

See ENGINES

Burned,Sticking Weak valve springs or Replace valves and/or

or Broken Valves warped valves springs, See ENGINES

Improper lifter clearance Re-adjust clearance or

replace lifters

Worn guides or improper Replace valve guides,

guide clearance See ENGINES

Out-of-round valve seats Re-grind valve seats

or improper seat width

Gum deposits on valve Remove deposits

stems, seats or guides

Improper spark timing Re-adjust spark timing

Broken Undersize pistons Replace with larger

Pistons/Rings pistons, See ENGINES

Wrong piston rings Replace with correct

rings, See ENGINES

Out-of-round cylinder bore Re-bore cylinder bore

Improper connecting rod Remove and realign

alignment connecting rods

Excessively worn ring Replace pistons, See

grooves ENGINES

Improperly assembled Re-assemble pin-to

piston pins -piston, See ENGINES

Insufficient ring gap Install new rings, See

clearance ENGINES

Engine overheating Check cooling system

Incorrect ignition timing Re-adjust ignition

timing, See TUNE-UP

Excessive Leaks at manifold to Replace manifold or

Exhaust Noise head, or to pipe pipe gasket

Exhaust manifold Replace exhaust