Strange 2.5T Engine misfire problem w/multiple choice answer game. Come play.
- Thread starter Tchman2016
- Start date
N7turbo
2023 CX-5 2.5T ... 2024 MX-5 RF GT
Just to be clear, I put the EPB on, car in drive. Let off the brake, idle increased. Depressed brake pedal, idle dropped.
Good question!... I'm going to check those again tomorrow, I had seen the short term showing -4 or -7 percent at one point but don't remember exactly both readings.
Yes that's exactly the scenario TY!
N7turbo
2023 CX-5 2.5T ... 2024 MX-5 RF GT
Oil analysis to check for potassium.
Ahh, to indicate the presence of coolant.
My last oil change was at 34,500 miles and I'm currently at 36,200 miles. Is that a long enough period to show results? The coolant reservoir also shows coolant below the low mark. Halfway between empty and low.
I'm wondering if a compression test of each cylinder would be in order here.
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Ok, here are some live data screenshots from a drive this evening I recorded.
The engine exhibits the exact same problem to the same degree as it did before I changed the plugs today. Like the plug change did nothing. I honestly now think it has nothing to do with ignition coils or plugs.
Now i'm thinking it's timing related. That would make more sense. Oil control valve possibly? Burnt exhaust valves? Faulty EGR valve? The engine literally sounds like its knocking when the idle is so slowed and I hear a tin aluminium metal sounding clinking noise (similar to the way the little tab on top of a soda can would sound if you break it off and put it inside the empty can and shook it) when I rev the rpms a little like something is broken or loose inside but it comes and goes. Really bizarre
Anyway, i'm considering removing the new plugs, putting back the old ones and taking it to the dealer. I don't want them to say something to the effect that they see new plugs and give me a headache or trying to blame something on me. This may be over my head.
What do you all think? Something is really wrong here and i'm just drained from it at this point. Thank you to each of you all for your help and insight.
The engine exhibits the exact same problem to the same degree as it did before I changed the plugs today. Like the plug change did nothing. I honestly now think it has nothing to do with ignition coils or plugs.
Now i'm thinking it's timing related. That would make more sense. Oil control valve possibly? Burnt exhaust valves? Faulty EGR valve? The engine literally sounds like its knocking when the idle is so slowed and I hear a tin aluminium metal sounding clinking noise (similar to the way the little tab on top of a soda can would sound if you break it off and put it inside the empty can and shook it) when I rev the rpms a little like something is broken or loose inside but it comes and goes. Really bizarre
Anyway, i'm considering removing the new plugs, putting back the old ones and taking it to the dealer. I don't want them to say something to the effect that they see new plugs and give me a headache or trying to blame something on me. This may be over my head.
What do you all think? Something is really wrong here and i'm just drained from it at this point. Thank you to each of you all for your help and insight.
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- 2017 CX3 AWD
1700 miles is a very short interval. It'd be great if your sample yields no potassium/sodium. If the values are high, then you can address the problem. Can you check under the rad cap too?
Here are my two recent results from Blackstone showing coolant in oil. This level is not enough to impact the oil's lubricating properties. No impact on engine's performance yet.
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- 2017 CX3 AWD
Your ambient temps are way up there. I didn't know that there are two values. Do you happen to have stats for intake temp? I recall intake temp is higher than ambient because it is in an enclosed space. Would an excessively high value lead to a poor mix?
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- NS, Canada
I had these issues on my 2018 Mazda6 Signature. it was a dead cylinder and required an engine replacement.
Someone else on the site also had the same issue on their cx5 with the same engine.
www.mazda6club.com
Someone else on the site also had the same issue on their cx5 with the same engine.
2018 Signature - MIL - Misfire cylinder#2
Howdy, Just thought I'd share the latest with my 6. Current mileage is 105,000kms. Condition has degraded drastically. Car is now sputtering bad when stopped in drive, feels like it's going to stall. Idling low at 500-600 rpm. I have a check engine light now and it's throwing Misfire in...
Maybe EGR valve is stuck open? Thish would reduce power, increase temps, and cause a crap idle.
OMG i'm going to throw up! That's the exact same issue i'm experiencing. I'm so sorry to hear this happened to you and that whole experience makes me sick to my stomach.I had these issues on my 2018 Mazda6 Signature. it was a dead cylinder and required an engine replacement.
Someone else on the site also had the same issue on their cx5 with the same engine.
2018 Signature - MIL - Misfire cylinder#2
Howdy, Just thought I'd share the latest with my 6. Current mileage is 105,000kms. Condition has degraded drastically. Car is now sputtering bad when stopped in drive, feels like it's going to stall. Idling low at 500-600 rpm. I have a check engine light now and it's throwing Misfire in...
I don't understand why there is no code thrown for ANY of the cylinders misfiring like that let alone no check engine light on.
Would a dead cylinder cause the other cylinders to misfire like that?
I guess I need to throw in the towel, put the other plugs back in and take it to the dealer.
Or should I leave the new plugs in and drive it around until a code in the PCM appears or put back the previous plugs and drive it around?
Would their scan tool show a misfire code that mine is not for some reason?
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- 2017 CX3 AWD
In the thread linked above, someone noted the MAF sensor as the culprit. You can explore that aspect yourself. If all your cylinders are misfiring, the cause is hopefully something other than a dead cylinder.
I learned recently that the scanning process is not absolutely precise/perfect. The hardware/software combo can lead to different results. See if you can find a different connector or app to check again. Auto parts stores don't always have time to run scans. There are still things that you can do before turning it over.
With an extended warranty contract, is the dealership still likely to decline service? You shouldn't have to worry about the new plugs.
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- 2017 CX3 AWD
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- Canada
You raaang?
I've actually been watching this thread to see what the solution was and to offer help where possible. Unfortunately I've never run into this problem, and I've never seen any other reports on the forum about this. I was planning to try checking idle RPMs in Drive to check for idle changes on and off the brakes, but it looks like that's already been tested and confirmed by others as normal (outside of the misfiring).
@Tchman2016 I'd check the fine print of your extended warranty to make sure you follow the process outlined in making a warranty claim. Sometimes there are disclaimers saying you need to have a diagnosis performed by "X" dealer before the claim can proceed, so it would be a waste to take it to "Y" shop, have it diagnosed there, and then try to file a claim and have it rejected just because you didn't go to the "X" dealer for diagnosis.
If it were me, I'd put the original plugs back in (in the same cylinders if possible) before taking it to the dealer for diagnosis. When they run through their troubleshooting, the plug condition would likely help them figure out the underlying cause.
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Also, on the topic of no codes thrown for a issue like this.. I'm reminded of the time my rear differential took a s*** and I also didn't get any stored codes. I had a Honda dealership (who did an unrelated collision repair) tell me that if there was a problem with the AWD system, I'd see a code. And then when I brought my car to a Mazda dealer, they said the same thing. Meanwhile I was driving around with FWD only, and pulled the rear diff drain plug to see chunks and shards of metal mixed with gray, silvery fluid coming out, and no freakin codes stored.
It doesn't help your situation, but this is definitely one of those things where there should absolutely be a code present to help you figure out what's wrong.
It doesn't help your situation, but this is definitely one of those things where there should absolutely be a code present to help you figure out what's wrong.
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- NS, Canada
I eventually started getting codes but it took several months. Codes usually happened in parking lots when I was backing in/out of a spot or other slow maneuvers.
Mazda and my dealer were helpful through the process.
I believe it was only a single cylinder misfiring. Not all of them.
Basically if car was in gear and I’d put the ebrake on and let off the foot brake so there was some load on the engine. You could feel it was running rough and idle would dip down below 500rpm.
Daily driving on the highway you’d never know..it was slow speeds or at a stop where it felt off.
