Thegamechanger

Ok I need some help I'm posting it here because it won't let me post in trouble shooting part I've searched this problem for 3 months before deciding to create an account and posting here. I'm getting getting an intermittent misfire in rotor 1 during wot in high rpm most of the time just over 7k but it is not always consistent there will be days where it won't happen at all and I'm driving like my foot is glued to the floor and then others it will happen most of the time in 3rd gear on a hard pull but then go away for the rest of the night. It only happens in rotor one. The things I have tried are new plugs/coils/wires, cleaned maf and ess reset Nvram everytime I try something new, check cat solid as a rock, installed oil catch can because there was oil in the accordion, seafoamed through service ports. I wouldn't think it would be fuel pump because it only happens in one rotor, and I haven't checked compression yet but I will be doing it monday, but I don't believe that is it because there are not hot starting issues and no power loss that I can see. Also my ssv is not getting stuck or anything tested it and it is smooth as butter. Any input would be greatly appreciated. Thanks

9krpmrx8

iTrader: (46)

I would test your ignition wiring from the coils to the ECU. What type of coils, plugs, etc. did you use? OEM, ebay, parts store stuff? You are sure you got the right plugs and put them in the right location?

jtizzle88

iTrader: (2)

How many miles do you have? If the rotors have an imbalance in compression of more than 20 psi then it can also throw a misfire trouble code. Check compression on the front and rear rotor and see if the difference is greater than 20 psi. I agree with 9K make sure you did not get knock off ignition replacement parts. FYI: These specs are in the Rx8 service manual

Thegamechanger

I started off with the plugs first I got the stock ngks that still didn't solve it and then purchased some duralast coils because I wasn't trying to wait in the mail for online oem ones plus from what I read on here they fail pretty often then soon after that I tried the wires because that was the only thing I didn't change and the old ones were in specs resistance wise. But if the durlast ones were the culprit wouldn't it happen on rotor 2 as well. As for compression I will be doing that monday in my day off

Thegamechanger

And I also triple checked wire placement. But as for compression I don't think it would be that it runs like a top when driving normally smooth idle great pick for an rx8 and it has 108k miles

9krpmrx8

iTrader: (46)

Try this:

https://www.rx8club.com/series-i-tec...manual-248429/

Thegamechanger

Ok thanks I'll try that in the morning tomorrow

Thegamechanger

I did that rotor and it seems fine both rotors reacted the same pulled the ignition and it stumbles and dies

Krod26

What condition were your coils in when you replaced them? Was there any white spots on the backs? Also (and I know you already mentioned this) but check the cables again, the routing is important, make sure you aren't crossing them over and they have their bracket clipped in. In some cases high current will pass through the insulation. And on a side note what condition is your battery, alternator, and belt in?

Thegamechanger

Krod I check the cables today and they were fine except one wasn't fully seated because the connect to the plug is kind of recessed it looks like a small manufacturing error but I did make sure it is properly seated this time and they are I the little bracket. As for the old coils they had small white marks on all of them and I tested them and they fall within Mazda spec. The battery does have a dated label and looks like it could be a year or 2 old and the alternator has the system just above 14 volts while on and the belts are fine no cracking or squicking. I thought that loose connection might have been the problem because it was on trailing rotor 1 but I reset the kam and nvram again and it happened again third gear but if this info helps I was monitoring the fuel trims and cat temp while driving and the cat never went above 920 degrees Celsius just to double check its not failing from the misfire but the ltft was at like hovers at 8.59 while idling and went down to 1.56 while slowly bringing it up to 8.5k idk if that helps but idk what what systems to monitor to figure out this problem

Thanks

9krpmrx8

iTrader: (46)

The white spots means nothing and the idea that they have anything to do with condition of the coils is a misunderstanding by man, Mazda mentions this in the Technical Service Bulletin.

Now, when you say your LTFT is almost positive 9%, is this while watching the live data or from a data log while the engine is warm? Ideally, your LTFT should not be more than + or - 3% from 0. I would check for vacuum leaks.

Can you verify what codes you are actually getting?

Thegamechanger

That's from watching it live. The specific code is p0301 but it always just a code pending sometimes it will trip a solid cel if I get a misfire twice withing the same ride. I'll check for a vacuum leak again.

Thegamechanger

Today I was watching the live data my ltft was at 14.xx around idle but is slowly coming down to the 7's this is all positive, I did reset my pcm again after I seated the spark plug wire properly. Also my maf reading maxed out at 184 g/sec wot at around 8500 rpm which is usually where the misfire is happneing could it be going bad?

9krpmrx8

iTrader: (46)

How does she start when hot? If you don't find any vacuum leaks then I would get the engine compression tested.

Thegamechanger

I'll try to get it tested today for compression but as far as starting it starts up perfect hot or col without any hesitation

Thegamechanger

Update: I think it was carbon buildup in the intake because I took it for a very hard run and the cel blinked a couple times and I kept pushing her and it hasn't been back for 4 days so we'll see

bishop1950

Ignition coils are the weak link here . They will fail at high temps . Where they are mounted is in a high heat area . You state it misfires at high rpm ... on rotor one !
As others have suggested check all wiring to leading and trailing plugs coils , Replace spark plug wires as they may test ok but fail under high load !!
This is one of those head scratch er things !!
If it keeps doing it ... I would change out some new coils on that rotor .. wire set also ...

Griff

Thegamechanger

Thanks for the suggestion but its been a week and a half and still no sign of the misfire so the only think of it being was a carbon issue most likely in the intake but idk for sure but I took it out for a really hard run and hasn't been back since thanks for everyone's suggestions I really appreciate it.

Thegamechanger

Hey guys my cell came back I thought it had gone away but it hasn't I've been watching the live data and my ltft is consistently around 10% positive but after sitting at idle for some time it might go up to about 13% but it does not decrease with raised idle or a higher load on the engine but tonight when I was messing with the engine I had the maf unplugged while running and it pulled up p0301 p0302 p1301 and p0200 . I can see why it would throw the misfire codes but why the p0200 it only shows with maf disconnected.

9krpmrx8

iTrader: (46)

You need to stop messing with stuff and have your car checked out by someone who can properly troubleshoot the problem.