Check Engine Light

Septus

I've got a 2001 Mazda Protege with about 70,000 miles on it. I got my first ever check engine light several months ago. It was read as a random cylinder misfire, and my dad recommended that I not worry about it too much in the short term. Well I never went and got it officially checked out, and I got another light a couple days ago, which came up as the same code.

Now this morning the light was blinking for several seconds before staying on. Is a blinking light specifically an indicator that the problem is worse, or could the sensor creating just have toggled on and off or something? I can take my car back by an Auto-zone tonight, but if it just comes up as the same code as last time, I wonder if I can afford to wait until the weekend to take my car in.

bowen

Seems it could be a large number of things from a faulty EGR valve, to a catalytic converter problem, or a misfiring problem that is starting to cause damage. I'd get it checked out.

KMFurDM

Take it to a dealer or a good independent shop and get it taken care of. It could be the ignition system or fuel delivery system and it's worth getting it fixed ASAP.

Usagi

On some vehicles the number of blinks correlates with a specific problem in the engine. A quick google search suggests it may be the cylinder misfiring, or the O2 sensor or part of the catalytic converter. Is the car having any noticeable problems driving, or is the light just coming on for no reason?

Septus

When I was at Auto-zone I got a printout of some of the potential causes, I think one was a vacuum pump failure. I'll have to look at it again tonight.

The car isn't running any differently. I'm just trying to get a feeling for how urgent it is. It'd be pretty tough to take the car in before the weekend.

Balgair

If I were you, I'd just wait till the weekend. As long as you're sure you don't see/feel/hear/smell (taste?) anything wrong with the car. I'm not saying it's not urgent, but if it's not noticeable, I'm sure it can wait a few days.

On a side note, I once had a Subaru with a malfunctioning engine light that came on every couple weeks or so and indicated some completely inaccurate issue that was shown to not exist, on multiple occasions.

Oh, and I'm not liable if your engine explodes.

Smurph

In my experience if you have a misfire you generally know something is wrong. The car will run rough and vibrate when idling, stuff like that. And your gas mileage will go down. If your car is running fine I wouldn't spend money fixing something that you don't know is broken. Get it looked at, but don't fix anything just because an idiot light came on.

On the other hand if you do have a misfire, getting a regular old "tune up" will usually fix it for about $150 or so. Tune ups mainly mean changing your spark plugs and spark plug connectors. They will change a bunch of other stuff too like your air filter but bad spark plugs are generally what cause misfires.

Septus

I have, within the last 3 or 4 months maybe, started having the occasional situation where I'll be idling and the car will give a shudder. So my car is behaving differently, but not within the last day or two, as a result or cause of today's blinking light, nothing currently that makes me think it's an emergency that I have to get fixed ASAP.

Terrendos

Hold off for the weekend. You can last 4 days.

illig

A car will run forever with a CEL. Except for those times when it blows up.

No one can tell you over the internet if it'll be safe to drive for a few days.

LaPuzza

I know on my car (GTO), there's a combination of button presses at start-up that will show you the actual error codes. That way, you can see if it's a gas cap or something major. Check out a Mazda forum and see if there's a way to read the codes without special equipment.

Otherwise, treat it like pain in your arm with shortness of breath. If you'd see a doctor for that, go see your service shop. If you like to play the "it must be something I ate" card, wait til the weekend.

3cl1ps3

The thing with a CEL is it could be something minor like an O2 sensor (which isn't even necessary to get replaced, although your gas mileage will suffer), to something like a misifiring cylinder, which could end in the engine dying (or exploding).

Get it checked out, it can't hurt.

Suckafish

Have the spark plugs been changed recently? I've gone through check engine light -> misfires with my current car. One was because the spark plug was not in tight enough (minor) and one was oil slowly leaking into the cylinder (not so minor).

If you're comfortable enough doing so on your own, take the spark plug for the misfiring cylinder out and see if it looks abnormal.

http://www.gnttype.org/techarea/engine/plugs.html

Edit: forgot about the third misfire - a bad spark plug wire. This one was obvious when I took a look at the engine idling at night. There were sparks jumping from the wire to the engine.

3cl1ps3

Suckafish wrote: »

Have the spark plugs been changed recently? I've gone through check engine light -> misfires with my current car. One was because the spark plug was not in tight enough (minor) and one was oil slowly leaking into the cylinder (not so minor).

This would be the whole engine exploding thing that I was talking about.

eternalbl

Check engine lights turn on when a code is stored. They blink when a condition is currently happening. If you're driving and it starts flashing, it wouldn't be a bad idea to pull over and get it towed.

Anyone saying you shouldn't have this checked... well, if you have a misfire that means there's gasoline not getting burnt up in the combustion chamber, going down to your catalytic converter to be burnt off. If you leave it like this, the catalytic converter takes the brunt and those bastards aren't cheap. You can also foul your O2 sensor which isn't as cheap as the likely air filter, spark plugs, and ignition wires that it'll take to clear this up.