How to Tune up a 1989 Mitsubishi Mighty Max

Keep your Mitsubishi Mighty Max (Triton) engine working at its best.

Without a proper tune-up, your 1989 Mitsubishi Mighty Max will soon begin to show signs of decreasing power, performance and fuel economy, not to mention reliability. On the other hand, making simple checks on key components and systems at regular intervals will help engine efficiency and better performance. Better yet, you will keep emissions levels in accordance with local and federal standards just by following these simple steps.

Things You'll Need

• Slip joint pliers
• Screwdriver
• Wrench set
• Soap and water
• Lint-free cloth
• Ratchet and spark plug socket
• Small stiff brush
• Ignition points file
• Spark plug wire gauge
• Engine oil
• Ohmmeter

Instructions

1. Inspect and adjust drive belts every 15,000 miles (24,000km) or every year. Look for signs of wear like cuts, splitting, tears and glazing. Apply about 20 lbs. of pressure to the drive belt with your thumb between the pulleys. It should deflect 1/4-3/8 inch (6-10mm). If deflection is greater, adjust the belt. Replace it every 30,000 miles, or whenever you find signs of wear.

2. Clean the air filter housing and inspect the filter. It is important to keep dirt and dust from entering the engine. Foreign particles inside the engine act like abrasive compounds against metal parts, causing internal damage. Make sure the filter is not clogged with dust either; otherwise, enough air will not enter the engine, enriching the fuel/air mixture, which will result in poor fuel economy, increased emissions and possible damage to the catalytic converter system. Replace the air filter every 30,000 miles (48,000 km) or sooner.

3. Check or replace the Positive Crankcase Ventilation (PCV) valve. The valve prevents combustion blow-by gasses from going into the atmosphere. Disconnect the hose at the outer end of the PCV valve located in the right-hand corner of the valve cover using a pair of pliers or screwdriver. Use a wrench to loosen the valve and remove it. Blow through the threaded end of the valve. If the passage is restricted, try to clean it with spray solvent; otherwise, replace it.

4. Replace the fuel filter every five years or sooner if you drive under severe conditions-see the Tips section at the bottom for more information. If you have a carbureted engine model, the fuel filter is a conventional, inline unit attached to the fuel lines with ordinary clamps. Use a screwdriver to remove the filter form the fuel lines. Fuel injected models use banjo fittings to secure the filter to the fuel lines. You can remove it by using a back up wrench to hold the locking nut and another wrench to loosen the nut attaching the unit to the line.

5. Inspect or replace the distributor cap and rotor if equipped. Remove the distributor cap and wash the inside and outside with regular soap and water and dry it with a clean lint-free cloth. Inspect the cap for cracks, carbon tracks and corrosion; check the rotor for carbon build-up, cracks or damage. Replace if necessary.

6. Remove and inspect the spark plugs one at a time, using a ratchet and spark plug socket. Check the plug for carbon deposits and clean it thoroughly with a stiff brush if necessary. The center and side electrodes should be perfectly flat with sharp edges. Use an ignition points file to recondition the electrodes if necessary. Check the spark plug gap using a wire gauge-consult your vehicle service manual for the correct gap on your vehicle model. Apply a light coat of oil before installing the plugs by hand. Then, use the ratchet and spark plug socket to snug them in. Replace every 2 years.

7. Inspect the spark plug wires insulation for burns, cuts or breaks. Replace them if necessary. Using an ohmmeter, check the wire resistance by connecting the meter leads at each end of the wire. Resistance should be about 12,000 ohms per foot. Also, replace them every 50,000 miles (80,000km) or 60 months.

Tips & Warnings

• To locate and identify parts on your Mitsubishi engine, consult your vehicle service manual. You can buy one at most auto parts stores or consult one for free at most public libraries. To help the engine on your Mitsubishi Mighty Max work efficiently, perform a tune-up every 15,000 miles or every year, whichever comes first. And if you do a lot of hard driving-continuous stop and start, low speed driving, prolonged idle stops-perform specific systems maintenance on shorter periods.