bbyatv

My son and I have been crushing CEL codes on his 2005 RX-8 since we purchased it in October 2013. We have had and killed so many.

The last code we are getting is for a misfire that only occurs when the vehicle is in 6th gear at about 70-75 mph and about 4,200 - 4,500 rpm. It is throwing a P0301 with a P0171.

We do not get the misfire during other driving conditions.

We have done our research and read through the following thread (among many others).
https://www.rx8club.com/series-i-tec...t-here-222280/

Here is what we have done so far to address the misfire/lean codes.
-Replaced the coils with BHR coils and wires (all wires correctly run to the right plugs)
-Replaced the plugs with new NGK RE7C-L & RE9B-T
-Replaced the MAF (with an aftermarket unit)
-Replaced all of the fuel injectors with flow tested injectors
-Replaced the Secondary Shutter Valve (SSV)
-Replaced the fuel pump and added a fuel pressure gauge
-Replaced the 3 solenoid valves
-Checked the compression levels on both rotors (both in good shape)
-Checked for vacuum leaks carefully (none found)
-Reset NVRAM
-Always use premium gas

While we were doing these various projects, we were of course cleaning the carbon and other deposits from parts as they were removed and replaced.

We have not done any work on the eccentric shaft sensor (ESS) or the Cat.

I am thinking this issue might be related to the non-OE MAF. According to the video below the OE MAF is better than aftermarket units and using it can solve problems.


Any thoughts on going to the expensive OE MAF or other ideas/suggestions? (I know, we have already spent a ton of $, why not an OE MAF? Just not sure if it is really a fix as described in the video.)

Thanks,
Bruce

9krpmrx8

iTrader: (46)

Clean the ESS, then reset, then move on.

Also try troubleshooting VIA the FSM rather than just throwing parts at it.

Engine ----> Symptom troubleshooting

http://foxed.ca/rx7manual/2003mazdar..._S01_0016.html

bbyatv

Thanks for the feedback. As far as throwing parts at the issue, the only part that was thrown at it was the aftermarket MAF.

The coils, plugs, wires, and fuel injectors were original equipment and had over 70,000 miles on them. I am sure they were in need of replacing/cleaning and why not go with some quality stuff?

The SSV was a mess and throwing a persistent code. We likely could have cleaned it up, but the new SSV has an improved design with an increased opening and closing force as well a improved deposit resistance. Again, why not go with a better part while your already in there?

The fuel pump had fractured at the fuel line connection and had to be replaced as it was leaking fuel all over the top of the tank.

We replaced the solenoid valves because they were also original equipment, had gone bad and were throwing codes. I don't think we can R&R those guys.

So best I can tell, we are not throwing parts at a problem. Believe me, we do not have the $ to do something like that.

Also, the Engine ----> Symptom troubleshooting guide does not address a misfire that is only occurring at a certain engine/vehicle speed. The items that it does recommend have for the most part been addressed.

So that leaves the ESS. Can't hurt right?

Thanks,
Bruce

gwilliams6

Go with the OEM MAF, it works best in NA setups. .

Cameltoe

Certain engine-related sensors, OEM is best. Definitely try the OEM Air Flow Meter, and maybe even go OEM on the ignition coils.

My older Nissans built in the 2000s were very sensitive too. Engine sensors like cam and crank sensors and MAFs all needed to be OEM; a picky bastard it has. Good luck.

gwilliams6

Cameltoe, I agree OEM MAF sensor and O2 sensor are a must. But there are options for coils:

You have a number of options for coils:
- The Cheapest option: BWD/Intermotor coils from auto parts stores like Advance Auto. 4 coils, 4 plugs, and 4 wires can be had for around $190-220 total based on whatever promotion is running at the time, shipped to your door for free. They are considered to be the first coil revision and you should expect to need to replace them around 20,000 miles, 30,000 miles max. They often come with a "lifetime warranty" by the auto parts store, which could potentially be leveraged for perpetually new coils.

- The Best Upgrade: The BHR ignition coil upgrade can be had for around $500, which eliminates the need to continue replacing coils periodically, as well as deliverying a significantly stronger spark for minor mileage and power gains. It is a proven kit with top notch customer service supporting it. It includes the wires, you still need to add plugs ($80)

- The For-Sure OEM: Mazmart sells all 4 coils of the latest OEM coil revision (C) for around $250, (just the coils, you still need to add plugs and wires) Supported by top notch customer service. They will likely last longer than 30,000 miles, but we don't have much solid data on how long the latest coil revision will last.

- The Most Expensive option: Buying from a dealer will run you around $300+ for the coils, $500+ for coils, wires and plugs, and if you have them do the install, expect to get a bill for anywhere from $700 to $1,800. You may not get the latest coil revision. Yes, you are getting shafted if you take this option, so bring lube.

- The Highest Risk option: Ebay coils continue to pop up as counterfeit, mislabeled, dead on arrival, and have zero post-purchase support largely. They are the "cheapest" listed price, but when you add that $92 or whatever to the price of anything in the list above from having to do it over again, you can see that they are no longer the cheapest option. Do it right the first time. "Motor King" coils are popping up at an attractive price on Ebay, but are being proven as ineffective, to the point of being unable to get the engine fired. "Mazda" branded coils on ebay are almost always counterfeit. Check the seller's name though, since some of our vendors sell legitimate coils there. The price will be $200+ though. Anything sold as "Mazda OEM" under ~$26 per coil should really be considered as suspect and probably counterfeit.

Be wary of "LSx D585 coil upgrades", as not all D585 coils are created the same, and the standard generic D585 coil is not properly designed internally for the RX-8's ignition needs. They generally "work", but there are anomalies and performance issues that have to be solved, if they can be solved. Definitely NOT a plug and play option, even if it is advertised as "plug and play"

SakeBomb Garage IGN-1A Ignition Coil Kit
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