To control vehicle emissions and improve performance and fuel economy, automobile manufacturers began installing “on-board” pcs on vehicles in the late 1970s. Thus giving a monitoring system that continuously checks the readings from various sensors and switches on the “Check Engine” or “Service Engine soon” light each time a sensor just isn’t offering the correct information to the computer. Whenever the “Check Engine” or “Service Engine Soon” light appears, you will find a service code, typically referred to as the trouble code, saved in the computer’s memory circuit which really can be extracted and useful to help troubleshoot the challenge. Today’s computerized vehicle systems can actually enable you to diagnose and troubleshoot themselves if you possess right information plus some basic hand tools.
Should you be experiencing a drivability problem, pick is always to extract any “trouble codes” on the vehicle’s computer. Are mainly essentially the most commonly experienced drivability problems and also a short description with the items components may very well be affected. Every time, these suggestions are assuming the engine is mechanically sound (camshaft, pistons, timing chain or belt, valves, etc). The engine also need to wear good tune (spark plugs, wires, distributor cap and rotor, air and fuel filters been replaced, etc). The ignition timing and base idle speed also have to be adjusted properly.
Complaint #1 – I HAVE AN INTERMITTENT “CHECK ENGINE” LIGHT FLASHING
A good intermittent “Check Engine” light is an indication than a service code has long been stored in the vehicle’s system. First, extract the service codes before making auto repairs. One common sensor that produces a good intermittent “Check Engine” light is definitely the Oxygen Sensor.
Complaint #2 – MY CAR STARTS HARD
Hard starting might be the result of several items. First, inspect all vacuum lines within the engine and replace them if any cracks or brittleness can be found. In the event your vehicle is carbureted, the choke system has to be working correctly before any sensor exams are performed. Whether it’s operating correctly, the Coolant Temperature Sensor could be affecting the way the passenger truck starts. On fuel injected vehicles, the sensors that can commonly be due to this condition include the Coolant Temperature sensor, Manifold Absolute Pressure (MAP) Sensor, or even the Mass Venting Sensor.
Complaint #3 – MY FUEL INJECTED CAR IDLES ROUGH AND STALLS AT STOP SIGNS
Stalling at stop signs whilst the vehicle is set in gear on carbureted vehicles can be the effect of a failing Idle Speed Control Motor. On fuel injected vehicles, it is best to search for failure while in the Manifold Absolute Pressure Sensor, Mass Venting sensor, or restricted fuel injectors. If you suspect restricted fuel injectors, we propose running an in-tank fuel injector cleaner previous to automotive troubleshooting procedures.
Complaint #4 – MY CAR IDLES ROUGH
Rough idle is most frequently caused by a tune-up problem or vacuum leak resulting from deteriorated vacuum lines. Once these parts happen to be replaced or eliminated, the sensors that is certainly to blame include: Coolant Temperature Sensor, Manifold Absolute Pressure Sensor, Air Charge Temperature Sensor, or Idle Speed Control Motor. Look at auto repair manual to your testing of every from the sensors.
Complaint #5 – THE ENGINE Generally seems to IDLE ERRATICALLY, Far After which WAY Back off
All of the items which may cause an erratic idle add some Throttle Position Sensor additionally, the Idle Speed Control Motor.
Complaint #6 – THE ENGINE HESITATES ON ACCELERATION, BUT ONLY Even though the ENGINE IS Warmup
If you ever possess a carbureted vehicle, first be sure the choke technique is functioning properly. A hesitation on acceleration through the engine warm-up period may suggest an inability within the following areas: Coolant Temperature Sensor or Air Charge Temperature Sensor.
Complaint #7 – THE ENGINE HESITATES ON ACCELERATION AFTER IT IS FULLY Moderately dewrinkled
A hesitation or stumble during acceleration may perhaps be a result of the Throttle Position Sensor (if thez engine is carbureted or fuel injected).
Complaint #8 – I’m EXPERIENCING POOR Gas mileage, And infrequently SEE BLACK SMOKE From the TAILPIPE
This is generally attributable to a very rich air/fuel mixture. This is certainly commonly the effect of a defective Oxygen Sensor, Coolant Temperature Sensor, Manifold Absolute Pressure Sensor, or simply a bad Mass Air-flow Sensor.
Complaint #9 – Concerning POOR Gas mileage As well as, BUT There won’t be SERVICE CODES During the COMPUTER
Sluggish performance is normally caused by plugged or restricted injector nozzles, you certainly can use an in-tank fuel injector cleaner to support restore performance.
Complaint #10 – THE ENGINE Usually “PING” OR “KNOCK” AFTER Its WARM
The primary item to examine is definitely the base ignition timing. You might need correct, the electronic component to test, in case your vehicle has one, would be the Knock Sensor. An inoperable knock sensor will not likely send a proof to the computer to retard timing therefore pinging may result.
Complaint #11 – MY CAR SURGES AT HIGHWAY SPEEDS
Surging at highway speeds is frequently caused by a lean air/fuel mixture. This is often a result of a failing Coolant Temperature Sensor, a defective Manifold Absolute Pressure Sensor, or even a Mass Venting Sensor problem.
Complaint #12 – MY ENGINE Includes a CARBURETOR And it also DIESELS (“RUNS ON”) AFTER I Shut off One of the keys
Engine “run on” is generally due to a superior idle speed setting the consequence of a defective Idle Speed Control Motor, an inaccurate adjustment, or excessively advanced ignition timing.
Complaint #13 – I AM EXPERIENCING A “ROTTEN EGG” SMELL OUT OF THE TAILPIPE
Rotten egg smell outside the tailpipe is attributable to a relatively rich air/fuel mixture or by running leaded fuels in the vehicle equipped for unleaded. Overly rich fuel mixtures could be the result of leaking fuel injector, a negative Oxygen Sensor, or defective Coolant Temperature Sensor.
Complaint #14 – MY CAR “BUCKS” AND OCCASIONALLY BACKFIRES
Except for a mechanical or ignition kind of problem, bucking or backfiring is usually caused by defective Manifold Absolute Pressure Sensor, a failing Mass Air-flow Sensor, or maybe a bad Throttle Position Sensor.
As we discussed, a lot of the sensors of any computerized vehicle system may produce identical kinds of drivability problmes. However some inexpensive hand tools as well as right troubleshooting information you are able to diagnose and repair the electronic computerized systems on today’s vehicles. Recall the above merely to use like a guideline for testing. Frequently, other components or sensors could cause the same symptoms. Consult the manufacturer’s auto repair manual covering your distinctive vehicle before proceeding with auto repairs.