I have a 2004 with 127k that has a re-man engine that only has 10K on it and I have been having a backfire problem. If I put my foot into it my 2nd rotor registers a backfire above 6500. I have tried swapping my 1st and 2nd rotors coils/spark plugs and the problem is still in the second rotor. The coils have less that 25 k on them and my plugs and wires have 10k. When the CEL flashes I do not notice any difference in power, but I back off until it goes away. I have reset the ESPS and it still backfires above 6500 when i put my foot in it. I can sustain 6500+ if I do it gently but it does not like it when i do it quickly. Secondary fuel injector on rotor 2? Other ideas?

 

Hmmmm, have you checked to see if your cat is glowing red after driving for a while?

 

No, but my CAT went out before my last engine did. I got a new one and i know that smell. On a side note, F CARB, the only one that's legal in California is the Mazda one... Lame

 

I know your coils are not that old but I had stock coils fail after 15,000 miles so I suggest testing them.

Use the FSM or this

https://www.rx8club.com/series-i-do-yourself-forum-73/diy-testing-all-rx-8-coils-gm-ls2-yukon-coils-sparkplug-wires-222641/

 

I have been trying to justify upgrading my coils but if the oem coils were the issue the problem would have moved when i swapped the coils between the rotors.

 

Did you swap wires?

 

I don't think they will fit if i switch them. I bought a 8.5mm Magnecor set and at first i had no issues, but i did start to have problems. Before that i a had a MDS make your own for a 4 banger but that was not water tight. Do you think should try the MDS on rotor 2? As long as it does not rain... lol.

 

Where in cali are you? The cali guys are pretty cool, I am sure someone has an extra set of factory wires laying around. I had a couple of sets but I think I have given them all away already.

 

If it the wires i still don't understand why it would be a consistent problem. I would think it would be more random?

 

Hard to say man, but without eliminating the plugs, coils, wires it's hard to move on diagnosing the problem. I had a misfire issue just like this but it ended up being a bad coolant seal and I had to replace the motor. But with me I was able to eliminate ever other possible cause leading me to that conclusion.

 

Sounds like i should try my old wires and maybe buy a compression tester... The backfire could be because of the secondary fuel injector on the second rotor, right?I figure its a fuel/air problem... hopefully.

 

Well rotary engine compression testers are expensive. You can use a regular compression tester if you remove the check valve but it's still not easy. Fuel injector problems are rare, I doubt it's that.

 

I had the same problem right now, engine light stays on and start flashing after 5000 rpm, I had engine code saying second cylinder is misfire. Tomorrow I'm going to put 4 new coils and see if the engine light and misfire would go away. Also at the same time I had my engine flooded this morning too so two problem at the same time. Hope the new coil solve every problem. I got new NGK wires and plugs brand new waiting for the new coils too so they all ready to go on the engine tomorrow.

 

I tried a normal compression tester on the last motor and it didn't give me any useful information, plus this engine does only have 10k so I really hope its OK. It just seams odd the issue is repeatable and consistent. I think ill try my old wires later today.

 

So I tried my old wires and I still have the same problem. The coils, plugs, wires all seam to be ok. Anyone got any ideas?

 

Well i guess its time to do what the FSM says to do. I just need to get my OBD-2 from my buddy and ill start with the freeze frame data and move from there.

 

make sure you didnt crack the porclin on one of the plugs. i did this once and it was easy to figure out wich one.

hood open preferably shady or dark under hood, car running have someone give it some gas. i could see/hear the arc to the "block". do not touch it.

dont know if this helps but worth a shot

 

I don't think it is the plugs because when i swapped my coils from rotor 1 to rotor 2 i swapped the plugs also. The problem didn't change to the first rotor. The really funny thing about this is when i am stationary it revs all the way to fuel cut off just fine. It only when i am moving and whomping on it that i have the issue.

 

clean maf, ess, and air filter.idk

 

Of course you are not under load or using all the injectors. You will chase this problem until you properly diagnose it.

 

I will be getting my OBD-2 back tomorrow, i continue the troubleshooting then. I plan on following the FSM line by line... I was just hoping someone that had a similar issue and had some insight.

 

So I got my started. With new ngk spark plugs but the cel still on flashing for code p0320 or p0302 don't remember the code number but call for misfired cylinder 2. I think I need to replace cat and injectors or clean them up.