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2003 Mazda 2 - 1.25 gasoline - Misfire P0302


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rubencouto
New User

Sep 19, 2017, 6:37 AM

Post #1 of 6 (132 views)
2003 Mazda 2 - 1.25 gasoline - Misfire P0302 Sign In

Hello!

My 2003 Mazda 2 (1.25 liters, gasoline) is showing the P0302 error code. The cylinder 2 has been misfiring. The symptoms are:

- Check Engine Light starts to flash and then is on;
- Car hesitates during acceleration, specially going up;
- Engine runs rough and idles are also rough;
- Car has a notorious lack of power.

Other "peculiar" symptoms are:
- If I use the car throughout the day, it keeps getting better. That is, if I use it long enough the engine hesitation reduces and sometimes, at the end of the day, it shows NONE of the previous symptoms (even the check engine light doesn't come on).
- Another thing is that I have tried to simply turn it off and back on and on maybe two or three occasions, the above symptoms have disappeared (the engine hesitation disappears).

My first option was to change the spark plugs for some new ones. That didn't work.
Then, I checked the wires (from the spark plug to the coil) using a multimeter and the resistance is present and constant in all wires so I figure they must be ok.
After that I checked the fuel injectors. I swapped the number 1 with the number 2 to see if the misfire would move to cylinder number 1. However, the misfire is still in cylinder number 2.
I also tried to swap the first spark plug with the second (although they are all new), to see if anything changed, with no success.
I tested the ignition coil using a multimeter and it seems to be working fine (the thing is that I made these tests during the evening, when usually the misfire doesn't occur or is very rare, if I have used the car during the day).

What can you suggest that I should do next?

Thank you for your help!


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Sep 19, 2017, 9:06 AM

Post #2 of 6 (115 views)
Re: 2003 Mazda 2 - 1.25 gasoline - Misfire P0302 Sign In

That vehicle is not sold here in the states, so advice is limited.

First you need to actually see is if the coils' secondary is firing and creating enough energy.

Do you have spark from the wire on that cylinder. They make an adjustable spark tester. The spark should be able to jump a 3/4 inch gap.

Ohm checking coils can be inconclusive because you are checking them when they are non operational. The better way is testing the coil's output capability using a spark testing device. To check the primary side of the coil using a lab scope with an amp clamp is more conclusive.






Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Sep 19, 2017, 9:11 AM)


rubencouto
New User

Sep 19, 2017, 9:22 AM

Post #3 of 6 (98 views)
Re: 2003 Mazda 2 - 1.25 gasoline - Misfire P0302 Sign In

Hello!

First of all, thank you for replying!!

I don't have such a device to test the spark that comes out of the coil. But maybe I can see if I can get someone to lend me one. Is it possible to build one of these testers?

But, if the problem is in the ignition coil would you say that it would be consistent with the fact that the more I use the car the less engine hesitation (thus, the less misfire) I get?

I have no expertise in any of this (as you may imagine), but I find it puzzling that the engine works better with usage. Could it have anything to do with the temperature?

Thank you!


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Sep 19, 2017, 9:33 AM

Post #4 of 6 (92 views)
Re: 2003 Mazda 2 - 1.25 gasoline - Misfire P0302 Sign In

You can also use a 12 volt incandescent test light probe tool to check spark. Don't use an LED test light. Hold the probe inside the boot while someone starts the engine and slowly move the probe out of the boot and see if the spark is jumping to the probe's end. The test light has to be grounded or else if there is spark it will find its way through you, which is painful!

Temperature can affect the coil windings. Coil may fail when the windings get hot.

If you see you have no spark, you need to check to see if the coil's primary is functional. The coil primary needs positive battery supply and a triggered ground. The ground side is probably triggered by the engine computer, but don't have any service information.

12 volt incandescent test light is a invaluable tool for checking electrical circuits on vehicles. They are relatively cheap and easy to find.







Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Sep 19, 2017, 9:38 AM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Sep 19, 2017, 11:11 AM

Post #5 of 6 (76 views)
Re: 2003 Mazda 2 - 1.25 gasoline - Misfire P0302 Sign In

That spark tester costs about $3.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Sidom
Veteran / Moderator
Sidom profile image

Sep 20, 2017, 12:35 PM

Post #6 of 6 (50 views)
Re: 2003 Mazda 2 - 1.25 gasoline - Misfire P0302 Sign In

You want to follow the advise that HT & DS have already posted...

In addition to that you may to take a compression reading on all the cyls..

I'm not familiar with this model but if the comp test is good, you may want to see if the valves are adjustable, if they are, go ahead and adjust them...






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