Series I or Series II (2009-2011)
?

 

Codes?

 

This is probably in this thread but its so long I thought I would post it and hope to be given forgiveness if it is one of the items covered. Another thing that can cause Engine misfires are the selenoids. One way to check is remove one of the (Probably brand new plugs you put it to try to get rid of this problem) Look to see if they are black which is an indication that your running too rich. Or too much fuel or not enough error. My car is a 2004 with a lot of miles but had gone through (previous owner) serious engine work like a rebuild or possibly a swap. As common as plugs, wires and coils are there are times that you can do all that and still have engine misfire.

So if all else fails or just to check before you start replacing everything else maybe take a look at a spark plug where you getting misfire codes from.

I got help fixing this from a southern gentleman who advised replacing all three instead of testing each one and only swapping out the bad ones. I failed to heed his advise and regretted it. *Getting at these parts is a little bit difficult so doing it twice wasn't my idea of fun.

 

Thanks for this thread. It has been very helpful.

 

wow, very comprehensive and helpful!!!! Great job.

 

Hi all. Bought my first RX8 in June 2017. I'm in love. It's a 2008. Had only 65,000 miles. Ran great until December. Started missing and running rough. Went to local Mazda rotary expert and that didn't go well. Ended up at dealer who questioned compression but fixed with new plugs wires and coils. Fast forward to Wednesday night this week and it ran great coming home from work on an easy drive. Woke up the next morning with a miss and the engine light on. AutoZone pulled a cylinder1 misfire. Since it doesn't have cylinders that didn't inspire confidence. So I talk to the dealer and they say I probably need a compression test. Problem is they want $295 and I see on the forum it should only be an hour of labor. It normally runs like a dream so it's hard for me to believe it has a compression problem. The computer seemed to even out the miss somewhat just in the trip to AutoZone. No idea how to find a non dealer mechanic locally. The most highly recommended guy only works on his own race cars now. I only run premium gas. It could use an oil change but I keep the oil topped off. Every few months it is low on coolant/water, but I had read on the forum about the evaporation through the overflow and reservoir so I assumed it was that since there is never a puddle or stain under the car and my engine compartment is dry. The oil doesn't show any signs of contamination. I don't really have the facility or tools for much DIY since I don't even have a jack!

 

The cylinder term still applies when using generic scan tools.
You need the code number.
If you have an Android device, get the Torque app and a Bluetooth OBD dongle, both for less than $30.
You can scan your own codes and monitor your systems to learn how to troubleshoot your own problems.
These cars run great with failing compression, until they don't.
Start it when it's cold, pay attention to how quickly it starts, run it until it's good and hot, shut it off, then re-start it.
If it doesn't start as quickly as when it's cold, then you can assume it's failing.
Mine is in the low 6 and high 5 range, still runs great, but takes an extra second or 2 to start when it's hot.
If you are physically able, and have a place to work on your 8, I highly suggest you start investing in at least a jack, a pair of jackstands, and some basic tools, unless you have hundreds, and even thousands of dollars to spend having other people work on your car.
They are high maintenance, but many of our common problems are easy fixes.
They're not hard to work on.

https://www.rx8club.com/series-i-tro...isfire-242088/

 

Have you ever performed a compression check on the car? You should have done it before purchase.

Unless you can find a local rotary shop or member that has a compression tester, just pay the $300.

If you want to DIY, you could buy a rotary compression tester and test it yourself, but you also need to buy tools.

That said, DIY is a good idea on this car. Even some dealerships can be clueless when it comes to this car.

As for coolant loss, I think it's a good idea to test the reservoir cap with a tool. Caps get old and they just can't hold pressure as well.

 

Cylinder 1 misfire means rotor 1. Misfires are not a symptom of low compression on their own, so leave that alone for now. Invest in your own OBD reader ($15) and get data. It could be your coils again, it happens. If not that, you could have weird airflow metering problems. But to diagnose that you need data.

 

Hi and thanks. The code was P0301. It's running great now and the engine light went off! It starts well cold or hot. I've never known a car to self-correct and the engine light to go off. Could it have been bad gas? Or something in the fuel? I had let it get really low before the previous fill up about a quarter of a tank before the engine light came on.

 

What is the difference between a solid CEL for a misfire and a flashing one?

And can the first mask the second?

I ask because about two months ago I started getting a solid CEL with two codes. The fist was PO301 and the second was PO301 pending. The car ran fine and it would stay cleared for 2- 5 days and then come back. I did a search and found a thread that spoke of changing the wires, so I did that. No change. I checked the coils. The bottoms were all good but the head on the first one seemed a bit loose so I pulled it off an found it was all burnt up. The rest were good so I replaced the coil and the misfire code for rotor 1 went went away.
But as soon as I took the car for a test run I started getting a flashing CEL every time I went over 4 grand, in gear, and after flashing for a while I would get a solid CEL. This time it's a po302 and a 302 pending. So I changed all the coils and all the plugs but nothing helped. Now I can drive as long as I take it real easy but as soon as I drive normal the CEL starts flashing again. If I take my foot of the gas it stops but if I don't catch it in time I get the solid CEL with the same two misfire codes.

I gutted my Cat over a year ago but ran it disconnected just to see if there was some obstruction in the exhaust. I did the peddle stomp, ran injector cleaner, cleaned the MAF and ESS and even put the original mazda wires back on but nothing changes.
A compression check came up good across the board and the car runs like a champ. I just keep getting this new code.

So I'm wondering if the new code isn't new and was just masked by the first code and what the difference is between the solid and flashing CEL's?

 

Can you get an OBD reader and check you fuel trim data on a warm idle?
It should be zero. If it's not, something is wrong with the MAF or thete is a vacuum leak.

Other, more invasive possibility is you have a poorly functioning injector, but since the 302 came up after you worked on the car, Im learning toward MAF/intake.

 

I do not have a reader that does data. I will try and find one.
Thanks.

 

The flashing CEL tells you that are having a misfiring currently, while the solid CEL gives you the code you can use to diagnose.

Actually, if the STFT, LTFT and their sum are within ±10%, it's all good.

Over +10% means you are running lean, and under -10% means you are running rich.

Get a Bluetooth OBD2 reader that can read live data. They are usually around 30 bucks.

Agreed that it could be the intake, especially if it's running lean. On some older cars, it's not uncommon to have the accordion tube dry and crack as they age, and sometimes the MAF is not inserted correctly or the threads get stripped, etc.

 

Well after finding out there was no compression problem I took the car on a 600 mile trip. It was almost all highway driving and after about 100 miles or so I noticed that I wasn't getting the flashing CEL when I brought the RPM's over 4 1/2 grand. So I erased the solid CEL for the 302 and it never came back.
I checked the oil when I got back and it is exactly in the middle between low and high. I'm wondering if it could have been on the high side before the trip and if that had something to do with it?

 

Unless it was drastically overfilled, I doubt that was the issue. Assuming you know these cars do use oil, the top line on the dip stick is the full mark & bottom line is add mark. Keeping the oil level at full will not result in a misfire.

You can however flood the intake with oil if you do not use a funnel when filling. If you simply add oil without a funnel, oil can run down the top vent then into the intake. If there is a lot, I suppose this could cause a misfire.

A healthy running Renesis will be able to run to redline without a misfire.

HTH
David

 

 

any oil in the intake? clean maf, ess and 20 brake stomp. history of car? mileage? mods? cat? transmission? video?

 

^Yes, more info needed.

Don't forget to double check the order of wires. Sometimes people hook them up wrong.

 

also make sure the wires are seated properly

do you get a flashing cel when you drive it?

 

 

 

 

 

get rid of the k&n intake. do you have a cat?