Troubleshooting Ignition Misfires

Read Review On Troubleshooting Ignition Misfires

Diagnosing and correcting a misfire that develops on the track can be far more frustrating than trying to shape out why a car will not start. There are, however, some similarities in the middle of trying to decree the cause of a miss and why a car will not start.

Troubleshooting misfires can be nerve wracking. Is it indubitably ignition associated or is it a fuel problem causing the misfire?It may be caused by a mechanical problem within the engine or even a cooling law problem. Other than mentioning the need to check for a blown or leaking head gasket and a bad or low-pressure radiator cap, we will not dwell on the engine internals. However, cooling law problems are responsible for over 20 percent of "ignition problems."

Fuel law problems are more often than not attributed to ignition problems. Before delving too deeply into the ignition, rule out any basic fuel law maladies: A fuel pressure gauge will identify a weak fuel pump, clogged fuel filter, or collapsed fuel line. A warped carburetor base, worn throttle shaft, or other vacuum leaks will show up as a lean condition. A clogged main jet may pass a optic inspection if it is blocked by a piece of sand or clear plastic. If in doubt, use a piece of thin wire to make sure that the jet is not clogged. A blown power valve should be confident from an overly rich exhaust.

In the early days of the automobile, good wire insulation was poor at best. Some early engines even used bare metal for spark plug "wire." In those early times, simplicity was the norm and wires were routed as neatly as compel tracks. Today, wiring has become more complex. Insulation quality has improved many times over, allowing wires to be bundled and be more tightly routed. Unfortunately, high voltage and high impulse carrying wires are bundled with signal wires that carry pulses that are affected by high voltage much the same as a compact car is buffeted by a tractor-trailer on the highway. Principal signals are corrupted or lost. This can succeed in a misfire.

A short checklist will help in determining the source of the problem:

· Using solid-core spark plug wires, along with the coil wire, can induce an unwanted signal into the ignition amplifier, causing the amplifier to trigger at the wrong time.

· Poor connections on whether end of coil and / or spark plug wires may cause a misfire.

· Bad crimps or connectors not seating on the plug or in the coil can both cause problems.

· Sometimes, a diminutive moisture inside the plug wire boot turns to steam and blows the wire off. A thin film of oil will sacrifice corona and will help the moisture to escape.

· Spark plug wires must be separated. If possible, do not run them parallel to each other.

· In rare instances, having the coil mounted too close to the amplifier can cause problems.

· Do not run the coil secondary wire through the firewall with the seeder leads or the alternator lead as this can cause erratic performance due to "noise bleed over."

· A weak ignition can cause a misfire, reduced power, or poor performance. This may be the succeed of a low battery or a malfunctioning alternator.

· Poor power connections, or wires and connectors that are too small can sacrifice ignition output.

· A scholar switch not rated for the application can restrict current flow sufficient to cause poor operation.

· Weak or damaged ignition components may work satisfactorily with a well-charged battery and cool conditions, but when the battery loses its covering fee or the box heats up, misfiring will occur. Low voltage and higher temperatures both want the ignition to work harder.

· Parts store switches might work well for a 10-amp blower or a 100-watt light but the ignition switch on current racecars may need less than 100 milliamps. This small amount of current may not burn through a thin film of moisture or over an oxidized set of contacts. quality switches are a great and more dependable choice. A Mil-Spec amount on a switch gives you, or the supplier, a reference where you can check and collate the qualities and capabilities of a given switch. Make sure that the switch you have chosen or are using will work well in your application. A parts store switch may work most of the time, but do you use supermarket motor oil in your race engine?

Misfire or Stumble

A voltmeter in the dash of the car helps you or the driver diagnose a problem. It can alert the driver to a malfunction before it develops into a misfire. If the alternator quits, allowable power administration may allow you to quit the race with all electrical power advent from the battery. To achieve this, all non-essential electrical consumption needs to be curtailed as soon as potential after the alternator quits. If the tach starts jumping, or the car starts missing, it probably too late to start a meaningful conservation of power. How the engine acts, combined with when and where on the track the engine skips, misses, or flattens out are all factors that may be used to diagnose problems.

Some factors to consider when determining the cause of a load or Rpm induced misfire:

What is the battery voltage when the problem occurs? Twelve volts or less? Or in the middle of 13.5 to 14.5 volts? A12-v misfire normally indicates a lack of preserve power. To remedy this type of problem, you can sacrifice the spark plug gap, slow up the timing, and install an alternator or 16-volt battery.

A misfire at 14.5-volt is a diminutive bit more complex. Does the tach fluctuate or get erratic? Does the problem occur early in the race or practice, or is it all the time after the median in the race?

Always have a box and coil known to be good, along with an urgency or test harness and a direct coil-to-distributor wire available. If, after changing these components, the problem does not go away, look for a bad ground or a battery problem. Which way do the plates in the battery face? They should be aligned from left to right to preclude shorting in the turns due to centrifugal force. Where on the track does the problem occur? Diving into a turn? Off the turn or midway down the straight?

If a problem develops over time (10 or more laps), replacing components may "fix" the problem until everything heats up or the battery loses its covering charge. Tachometer performance may indicate the source of an ignition problem. An erratic tachometer reading or a zero reading may indicate a loose association or low battery voltage.