Diagnostics Services


  • Replacing the spark plugs, spark plug wires, distributor cap and rotor (if applicable), oxygen sensor, fuel filter and air filter.
  • Inspecting the fuel supply system, emission system, and ignition system
  • Adjusting the dwell, timing, fuel mixture to original specifications. If your vehicle experiences any operating or performance problems between maintenance intervals, that specific problem should be addressed by performing an engine analysis to isolate that particular problem. Our Engine Analyzer systematicly tests the engine’s starting, charging, ignition, fuel/emmisions, compression and cooling systems. Out of spec readings in each area are flagged to alert the technician to possible problems which can then be evaluated and addressed. A full diagnostic report is then delivered to you in your choice of paper or computer disc.

The ECM (electronic control module), or commonly know as your car’s computer, controls and monitors many functions of your vehicle. Here are some of those functions:

  • Adjusts fuel delivery
  • Adjusts firing of the spark plugs
  • Prevents wheel lock-up and skidding
  • Adjusts the vehicles performance to minimize pollutants
  • Adjusts speed of the throttle to optimize performance
  • Senses the environment outside and adjusts fuel/air ratio
  • Notifies drivers of regular service intervals
  • Alerts you to potential device failures

A malfunction of a sensor can provide erroneous information to the ECM and can result in the ECM ‘over-compensating’ other devises to try to correct the reading. The proper functioning of all your car’s sensors are imperative for your car’s optimum performance. They control your vehicles ignition, emissions, cooling, and fuel supply systems. Let’s understand their function:

  • Oxygen sensor measures the percent of oxygen in the exhaust to determine if the air/fuel mixture is too rich or too lean.
  • Crankshaft/Camshaft position sensor measures the rotation of the engine to know when to trigger fuel or spark.
  • MAP sensor reads changes in barometric pressure in order to adjust timing or fuel mixture
  • Mass airflow sensor- measures the amount of air drawn through the intake in order to compensate for altitude and temperature.
  • Coolant temperature sensor measures the temperature in the cooling system to monitor the engine’s operating temperature.
  • Throttle position sensor measures the position of the throttle linkage so air/fuel mixture adjustments can be made.
  • EGR valve position sensor- detects the opening of the EGR valve in order for the ECM to make adjustments and optimize performance.

Other output devices important for optimum performance:

  • EGR valve (emissions gas re-circulation) recirculates a measured amount of exhaust gas into the engine’s air intake, to lower combustion temperatures and reduce emissions
  • Mixture Control Solenoid used on computer-controlled carburetors, controls the blend of air/fuel to maximize power and reduce emissions.
  • Ported Vacuum Switch- senses engine temperature and opens/closes vacuum lines to emission-related components.
  • Idle speed control actuator adjusts idle speed to prevent idle fluctuations.
  • Control module/Ignitor- regulates and times the spark signal to the ignition coil for correct ignition without misfiring.
  • Ignition coil- converts the car battery’s 12 Volts to the thousands of volts needed to fire the spark plugs.
  • Fuel injector injects fuel into the intake manifold.

As you can see, there are many different components that contribute to the performance of your vehicle. Only a competent technician is qualified to perform diagnostic tests to ensure that your car is in optimum shape. If your vehicle has an operating problem, the problem has to be isolated and ultimately repaired. Our engine analyzer systematicly tests the engine’s starting, harging, ignition, fuel/emmisions, compression and cooling systems. Out of spec readings in each area are flagged to alert the technician to possible problems which can be evaluated and addressed. A full diagnostic report is then delivered to you in your choice of paper or computer disc. Mr. Tires Automotive, inc. welcomes all current and potential customers to visit our diagnostic center, see our new equipment, and meet our technicians. Our time is always available to you to discuss the current performance of your vehicle, and how we can improve it.