When a problem occurs with any car or truck, the act of isolating the trouble based on the symptoms is troubleshooting. While the act of troubleshooting will not correct the problem, it is a systematic, and logical, approach used to determine what component or system is causing the trouble.
A car troubleshooting guide is a list of nearly every conceivable symptom, or problem, a car owner might experience with her vehicle. Based on each symptom, a list of potential causes, what to check for, and possible remedies for each cause, are listed in order from most common, to least common. Then, a repair, or replacement of the part, is the next step.
Engine Fails to Rotate
When turning the ignition key, you expect the engine to come to life. The first time to attempt to crank the engine, and it does nothing, the instinct is to try and try again. If the engine does not rotate, here are some things to check.
Battery terminal corrosion – remove the battery terminals and clean the posts and terminals.
Battery discharged – turn on the headlights to determine if they are weak, if so, charge or replace the battery.
Clutch not engaged, or shifter not in park – cycle the gear shift to neutral and back to park to ensure it is fully engaged. Also, if a manual transmission, depress the clutch fully.
Broken or loose wires in the starting circuit – check all the cabling and connectors between the battery, alternator, and starter, for any sign of loose or damaged wires or plugs.
Engine Rotates but Fails to Start
Sometimes, when turning the ignition key to start the engine, the engine will rotate without ever starting. Attempting to start the engine for too long under this condition, and you’ll have two problems; an engine that won’t start, and a dead battery. Check the following when this symptom occurs.
Fuel tank is empty – sounds silly, but it has happened.
Fuel filter clogged – replace the fuel filter with a new one if the fuel filter is suspect.
Fuel relay switch tripped – check the owner’s manual to find the fuel pump relay switch location. Most vehicles employ a safety switch that shuts off power to the fuel pump in case of an accident. It’s not completely uncommon for the switch to trip because it’s bored. Reset the switch.
Bad fuel in the tank – while bad fuel will normally result in lousy engine performance to warn you of problems, it can also strike without warning. Remove a fuel line and drain some fuel into a jar to check for water or excessive debris. If found, drain the tank and refill with fresh fuel.
Fuel injectors clogged – this usually goes hand in hand with a clogged fuel filter. This problem gradually occurs, and should be corrected before it prevents the engine from starting entirely.
Engine Hard to Start
When experiencing an engine that takes longer than normal to start – hard to start being the symptom – there are a couple of things to look for.
Dirty air filter – examine the air filter and look for signs of dirt or build-up. Without an adequate flow of air, the engine cannot start. Replace the air filter is it shows signs of staining or excessive grime.
Fuel system vent lines clogged – the best way to check for this condition is to remove the fuel tank fill-cap and attempt to start. If the engine starts with little problem, have a mechanic check the fuel vent lines for stoppage.
Battery charge low or discharged – check terminals and battery charge.
Sparkplugs defective – remove and check a couple of the sparkplugs. If the ends are burnt or appear excessively dirty, replace all the plugs with new. Be sure to properly set the plug gap before installation.
Engine Misses While Running
An engine misfire is when one or more of the engine spark plugs fail to ignite the fuel in its combustion chamber when it is its time to do so. When this happens, the engine will lope or sound like it is dying for that second. Some of the items to look at when an engine is missing are listed here.
Engine timing out of adjustment – on fuel injected, electronic ignition vehicles, the timing is a function of the onboard computer. However, the computer relies on inputs from sensors such as the oxygen sensor, the mass-airflow sensor, and others to determine ignition timing properly. Have a reputable automotive garage check all the sensors. Another issue might be bad sparkplug wires or connectors. Check all the wires and connectors for signs of hotspots or poor contact.