Mordae

First off a quick thank you to the veterans of these forums. I’ve been lurking on the forums for about 5 years and owned my RX8 for about 3 years now. I’ve read hundreds of threads that have been very informative and helped from picking a car to rebuilding it. I wouldn’t be able to own this car without these forums.

I had my engine rebuilt by Rotary Resurrection (+1 to his many recommendations on this forum). The engine failed ultimately from a clogged cat, but I am pretty sure coils were the primary failure point. I bought the car cheap at borderline compression numbers, so this has been planned, and I’m a bit surprised it lasted 2.5 years in the condition it was. While I had the engine out, I took the opportunity to install a few aftermarket parts, which I’ll list below. The only really relevant one is the ignition, but for completeness:

Aftermarket Parts:

• BHR ignition (+new plugs)
• BHR midpipe
• BHR engine mounts
• ACT Flywheel (Mazda CW)
• Exedy stock replacement clutch

The main issue I’m having is a P0302 Cyl2 (rear rotor) misfire. It occurs at high load/rpm most often, but I occasionally get a blink at idle. I have not confirmed if the idle misfire is more likely immediately after a high load/rpm scenario. For example: sitting in the driveway, I can rev to 9k with no problem. Doing a second gear pull will cause a flashing light continuously about 80% of the time.
Obligatory link to the Misfire Thread in case anyone got here and hasn’t read it.

Steps I’ve taken:

• Tested the BHR ignition with
  this
  this
  tester
  
  • Checking the plugs, the cyl 2 ones I pulled had a bit of carbon, not much. I will replace them again when I solve the issue. Unfortunately, I didn't think to check the front rotor to compare.
• Cleaned fuel sock (was fairly dirty)

Steps I plan on taking:

• Confirm fuel injector wiring.
• Replace SSV actuator
• Check SSV Solenoid
• Replace fuel pump assembly

Symptoms: (ie every little thing I’ve noticed)

• P0302 Code - no jerking, etc
• Very Slighty rough idle – there is a “burp” about every 3 to 5 seconds. I have no idea if this is normal or not.
• SSV ticking – checked for vacuum response. Seems to start moving at less than -3.6 kPA. The way I read the manual this is out of spec.
• Whine/ tone coming from fuel injector area of engine bay. I haven’t diagnosed the source.
• Slight hiss coming from purge evap sol area (I have a purge evap code. Planning on replacing next time I remove UIM, but not positive the noise is related.)

Any recommendations on order for troubleshooting or something I have overlooked is welcome. This scenario is a bit different from most misfire posts I've read through because I have to also consider all the ways I could've fucked up the reinstall. I have ruled out ignition for now (maybe incorrectly). I also don't think its intake related as I've been over the system checking for leaks. My LFT is ~8 ~4-5. I'm trying to compromise cheap, easy, and most likely in determining order of attack. I'm running out of easy, so I'll be digging in a little deeper soon. The load dependence biases me toward fuel system, but only getting the P0302 means its likely only affecting cyl2. That said, I just found the SSV issue and am not sure if it is related yet.

UPDATE SOLVED:

Life has been hectic and money tight the past few months, but I finally got around to the car again. In this time, signs of alternator voltage issues cropped up and, sure enough, the regulator was bad. I replaced that alternator and some other bits (including purge valve) in the apartment parking lot. Sure enough, the misfire is gone and the only code is from me missing a cat! It seems the alternator was bad the whole time and wasn't driving the new BHR coils properly. Thanks again for the suggestions and willingness to help!

TLDR:
Misfire that presented under high load or dropped load situations was caused by a faulty alternator.

Loki

iTrader: (1)

Is that +8LTFT at idle?
One othet easy thing is to clean the MAF and clear the ESS profile (press brake 20times with key in 'on').

If you change the rotor 2 coils to rotor 1, does the misfire also move to rotor 1?

Mordae

Sorry for going MIA. I'm working on finishing my Master's so time is hard ot come by atm.

I cleaned the MAF when I put everything back together and I believe once since then. I also do the 20 stomp after every change I make.

The +8 LFT is erroneous. I must've remembered wrong. I've been monitoring it this week and it has ranged from 3.9-5.4 at idle depending on the day.

The coil switching is an excellent idea. And will be next on the hitlist. As soon as I get an opportunity I'm going to take off the UIM and check my handiwork under there, and I'll switch the coils while I have the accordion tube off.

Unfortunately, updates will probably be slow coming until I defend my thesis, but I will update as I get things done.

Thank you for the help and suggestions

Mordae

Solved update: see main post edit