Diagnosis help
 

Was just wondering if hopefully someone here could help me diagnose an issue that has recently happened...

The car seems to have lost only a little bit of power under full acceleration, and at WOT when in gear, after giong to redline, I am getting the CEL flashing at me. It only happens after running to redline at WOT in gear, and it flashes for a bit, then it goes away. The light doesnt stay on. Has anyone else experienced this? Can I have the car scanned and will they be able to diagnose the issue? It happened this afternoon, and I am hoping it is not a serious issue...

Any help is appreciated, and Thanks in advance.

Oh yeah, 2004 with 70k miles, 6 spd, in case that info is needed to diagnose. Thanks again.

misfire
run higher octane
change plugs/coils/wires

yes, you should get it scanned, but it was most likely just a misfire

Also, I noticed after the fact that I was having some hard starts after shutting the car off...

I am thinking you are possibly right on the misfire, but is there no reason to be concerned? Like what caused the misfire?

I just filled the car up with gas earlier in the day, and filled it with premium, as I always do... The plugs have less than 3k miles on them, and the coils and wires are not too old either. I will try to have it scanned tomorow.

Also worth pointing out cjkim, the problem is consistent under those conditions... After running to redline under load it would give me the flashing CEL.

If it is a misfire and a plug is fouled, would this be covered under the mazda extended warranty for our vehicles?

Anyone else?

High RPM + Flashing CEL = misfire. You need to change your coils. If you already changed your wires/spark plugs 3k or so ago, then start by only changing the ignition coils. Probably not covered under a warranty since it is a normal wear and tear part. Cost you about $120 for all four and about 10-20 minutes of your time to install.

Thanks, I will give that a try. Do I have to get the coils from mazda or can I get them from just about any parts store?

I don't know that the aftermarket is making them. You can go to a local Mazda dealer to get them but shop around if you have more than one available. Some shops markup their parts more than others. Or you can get them online from a place like Mazmart and have them shipped to you. Getting them local gives you instant gratification and you pay sales tax. Getting them online will be cheaper, but requires you to wait and pay for shipping.

mazmart and finishlineperformance have them for a good prce. I got mine from Mazda because I wanted them asap. It was like $130. If you buy them online you might be able to get them for like $100 or so after shipping.

Thanks guys, I will make some calls today and see what I can find. I ran the engine a bit earlier, didnt get the flashing CEL anymore, but it still feels like it is not 100%... It could just be a mental block though...

Are there any tests I can run to make sure it is the coils? Money is tight ATM, and I want to make sure before I go spending money. Thanks again.

Heres the test to see if the coils need to be replaced.

Warm the car up for 10-20 minutes. Then, rev engine to HIGH and see if you get a flashing CEL. If yes, you need to replace the coils. Im sure there is some techincal test but I dont know it. If you are worried that wont fix it, then buy them from Mazda, install them, then see rev your engine high and see if you get the flashing cel and see if the car feels like it is running better.

Best case scenario, it works great. Worst case scenario, you immediatly take them off, give them a quick wipe down(just incase they got slightly dirty) and return them to mazda if they dont fix the issue.

Loss of top end power, misfires, Hard starts when the engine is hot could also be a sign of loss of compression. If coils wires and plugs don't fix it, A compression test would be up next on my list of things to look at.

Well that isnt good news... I will try getting new coils either tomorow or wed and changing them out to see if that fixes the issue. I really hope that is all that it is.

After more driving around today, starting the motor (either hot or cold) is difficult, it doesnt want to start, and struggles once it starts firing, gives a lot of sputtering and is very slow starting. I am getting the flashing CEL after everytime I run to redline in second gear, first gear I get it sometimes, but nto consistently like second gear. Power loss is all around, not just top end, but bottom end as well. Also, the engine note seems to sound different to me, but I dont know if it actually does or if this is a psychological effect because I think something is wrong...

Thanks for the help JMC and Socket, I will start by trying the coils, and hope for the best... And now, I am off to find a how to haha :)

that's a terrible test and doesn't necessarily means coils are dead. all that means is a misfire.. which we already know he has
use a multimeter or pull your plugs and look for any that are fouled.

Low compression would be great news. You're still covered under warranty for it. A fresh, new engine at 70K miles. Sure you'll need to give the car up for a week but they'll give you a loaner, and then your car will be strong as the day you first bought it. You might even want to go to the dealer before doing the coils and see if they will compression check it for you for free.

I actually wondered about this after I made that poast... I am going to go to the dealership tomorow, and have been quoted at $35.xx for each coil, I will ask if they will run the compression test while I am there. Does the test take long for them to perform?

Any more info on the MM test? What exactly am I checking for? Voltage drop across the 4 coils?

Let me look for it..

edit.. found it
https://www.rx8club.com/showthread.p...t=coil+testing

Thanks for that, will try that tomorow if the dealership wont do a compression test for free. :)

Well, I called the dealership...

The compression test is NOT free if that is not the problem... Which I think sounds like horse shit, and I might just call in to mazda coroprate and check that out... Also, the test would require me leaving the car there for a few days, which also sounds fishy to me.

Also, as an update, my CEL came on as a solid earlier this morning lol. Guess its time to do something before it takes out my cat or anything else.

Well, four new ignition coils seems to have fixed the problem :) .

And man, that is an easy fix lol. The hardest part was driving across town to buy them.

I'm glad the coils fixed your misfire issue. Does the car feel normal again?

get the plugs pulled. good chance they were fouled if your coils were bad.