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Matthew Wright

Avoid Misfires with New Spark Plugs and Plug Wires

By April 18, 2011

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Misfires didn't used to be such a big deal. Sure, you want your engine to run like a top, with no misfires or other out-of-sync stuff going on. But in the old days a misfire simply meant reduced power for a second and maybe an audible "hiccup" from the engine compartment. Replace your spark plugs and check your spark plug wires and you were good to go. Not anymore. These days even the tiniest, most imperceptible misfire will cause your Check Engine Light to come on, and you're back at the repair shop. It's more important than ever to keep your ignition system in good shape to avoid this trouble. Healthy spark plugs and spark plug wires are a good way to avoid trips to the shop for CEL (Check Engine Light) resets. These quick and easy hot-to guides are complete with photos of each step. Get to it!
How To Replace Your Spark Plugs
Inspect Your Spark Plug Wires
How To Replace Your Spark Plug Wires

April 20, 2011 at 1:35 am
(1) Dusty says:

On my car the computer can be reset after a repair is made by turning on the headlights- so they will stay ‘on’ during this action- and/or turning on the AC/heater fan (mostly something that uses power and with the key ‘on’) and disconnecting the battery for a moment. That will drain all electrical charge from the computer and the memory.

When the battery is re-connected, the system will be clear.

Downside: reset the clock, radio settings, allow the computer to make new “driver friendly” adjustments.

If the warning light comes back, the problem still needs fixing. Start over.

This might not work with all cars depending on how the computer is wired and what kind of memory is used.

April 20, 2011 at 1:38 pm
(2) Blain says:

If you go to your local O’Reilly’s you can use their diagnostic tool for free to check your codes and reset them. Much easier and less of a pain in the rear than draining your battery.

April 20, 2011 at 1:44 pm
(3) Bill says:

The check engine light has been a boon and bust for mechanic shops customers can have a loose gas cap and that can trigger a warning. Hard to charge someone for tightening their gas cap. One the other hand it builds trust and future business by being honest with the customer.

April 20, 2011 at 7:51 pm
(4) Alex says:

I had a platinum plug give me a scare… the little electrode inside the insulator actually broke, allowing the metal to slide down and ground out on the …um bent-part-thingy. I thought I’d trashed the engine (straight 6 bmw) because it would knock at idle. What a relief when it was just a bad plug. Change em! They’re cheaper than an overhaul! Peace Out.

April 21, 2011 at 11:56 pm
(5) Dusty says:

Autozone will also give an opportunity to copy a list of error codes from the device. The parts houses are not supposed to clear the computer, at least under the laws of my state. It is nice and easier if the guy will do it. The dealership will clear it for a one-hour service charge (they call it a computer diagnostics service fee), kill a $100 bill.

Buy parts, drive home and the error light is already back on?

Easier to just clear the memory my way.

Had a gas cap pressure leak once, bad seal. The Toyota dealership tried several gas caps from their parts department before finding one that would hold pressure. Charged for each one and for the total time in the shop. The law says ‘pay up.’ It happened again, the first Autozone cap was good. I buy from O’Riley a lot, too.

Over the decades the independent or small chain parts places have vanished. In any reasonable distance (for me) there is only the two parts houses named above and the dealerships.

April 22, 2011 at 12:34 am
(6) Dusty says:

To clarify about the battery in my previous comment: in this procedure the car’s main battery is only briefly taken out of the circuit. “Draining” or trying to fully discharge it would be very destructive to the battery and would create big problems.

Removing the battery from the circuit with the car shut down, then turning on things that can draw power, then turning the key to ‘start’ and letting it rest for a few moments allows at least my car and the other cars in my family that I have tried/needed, to clear the computer memory. Turn the key back ‘off’ and take it out of the ignition switch before reconnecting the battery. I think that the computer memory has a back-up power source that is a capacitive circuit intended to ‘keep alive’ the memory with a small voltage source (capacitor). The procedure bleeds this tiny amount of voltage to zero and the memory is lost. Reconnecting the car battery brings everything back to normal instantly except for the lost memory signal bits.

While the battery is disconnected, try (while wearing protective gloves; the white lead-compounds powders are severly toxic) cleaning the connectors and the battery terminals. Put a couple of drops of full-synthetic motor oil or other water-repelling oils like the newer gun oils on all the connector metal surfaces and drip a couple drops into the wire cable ends if that is easy to do. This will do a lot to prevent corrosion at the battery terminals for a long time. That corrosion resists electrical flow.

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