Misfire count

[Brahmajoe]

This is why i refuse to run anything less than 93 - on any of these newer high compression engines I run only 93 octaine - you can run 87 however from what i've seen on other cars you will see hire misfire counts and retarded timing, etc. I just run 93 (even though it hurts now) but I have not seen this at all on my end. Are you guys running 93 ?

87

Different tunes. ESS doesn't matter. It can't.
It does nothing until conditions are met then it shuts the engine off - and restarts it. 0 impact while running.

even with the drain from the aux battery?

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[ShadowsPapa]

87

even with the drain from the aux battery?

There is no "drain" from the aux battery. Once running the voltage is 14 or what your volt meter on the cluster says it is. Too much bad info out there from non-electricians.

 

[jebiruph]

I brought up ESS so the OP would know or to look at possible pending misfire codes if he ever gets the ESS disable message.

I can vouch for this. When I was having misfire issues, ESS disabling occurred before the misfire error codes.

 

[ShadowsPapa]

I can vouch for this. When I was having misfire issues, ESS disabling occurred before the misfire error codes.

It's pretty conservative but I see that as good. Even a suspected engine issue should disable it. Your findings would make sense.

 

[jwolfejt]

87

even with the drain from the aux battery?

11.2:1 compression and 87 octane - just saying. I know newer engines have more robust knock sensors and other features that help quell detonation - but I am going to stick with 93 here as I have not had nor seen this issue.

 

[ShadowsPapa]

Octane doesn't change misfires.
These may have a very high static compression ratio, but at below 2800 RPM much of that is bled off resulting in a lower compression pressure than what the dimensions would normally yield.
The longer intake runners also improve turbulence, decreasing chances of detonation.
The cooled EGR helps enable the higher compression ratio by reducing combustion temperatures when needed to control detonation. Cooling the gases in the chamber reduces pressure and temperature.

Spend the money if you desire - it's yours! ;-) It can't hurt anything.



Since I've been driving the 2020 more this week, the ESS started working fine again. It charged the batteries to above 12.44.
In fact, it was extremely well-behaved this week, the dealer was happy to get it and is already going through to sell it as a Jeep certified used vehicle.

When these are running, what you see on the screen as the voltage is what's there available to all systems. There's no drain on anything. The electronics have that 14 volts or whatever it is at that moment for anything needed.
If the cluster says 13 volts, then there's 13 volts for everything even if the batteries were at only 12.1 when the truck was started.

So I guess what I'm saying is this -
Misfires that are seen as excessive or problematic or beyond the dozen or two dozen every 20 minutes or so will cause ESS to not function. Minor misfires are normal and won't impact ESS operation - they are random, transient, and there's nothing else abnormal going on.
Abnormal misfires can cause ESS to not work.
ESS battery issues won't cause misfires. IF it's running and the charging system is kicking out over 12.x volts, it's got enough to run things.
The PCM will kick other errors if the voltage is too low - you'll know it.

This was mine in 10 minutes - 2 idling, 8 driving minutes, and ESS worked fine.
What's interesting is that the misfires were on

 

[Brojave22]

had a little misfire issues in the beginning of the fall, got the update from dealer, misfire stopped happening ( I heard it just allows the computer to record the misfires better). now every other start up, cold or from ESS the engine misfires and shakes. I shut it off and turn it back on and it clears itself. No check engine light, is it still recording the misfires? When i originally went to dealer they said there are no codes in the computer and they cant do anything unless it happens at the dealer

 

[Idlethunder]

My 22 JTR has very close to 2,000 trouble free miles on it since they did the cam/crank relearn just before Christmas. Before that, Jscan was showing at least 50 and up to several hundred misfires across all cylinders, with most on #s 4 and then 2, for any drive after a cold start. From delivery of the Jeep in March up until October, the vast majority of misfires were not noticeable without Jscan. Around the first of October that changed and I could easily feel and hear the engine running rough. These new misfires came after a hot or warm start. By that I mean I’d driven 25 miles or more and the engine was fully up to temp, then I’d park and go into a store for a few minutes and come back out and it was easy to tell the engine misfiring even without Jscan. Both types of misfires would cause the CEL to come on once or twice a week, and always when the misfire count shot up very quickly. Sometimes the light would flash and the truck would go into limp mode until I shut the engine off and let it sit for a minute. Before shutting the engine off, I could see code p0300. After restarting, the code was usually gone but it did store it a few times so my dealership had been able to see it. There were also 7 times during the 9 months between taking delivery and having the cam/crank relearn done that the Jeep died immediately after the CEL came on. When that happened, it took several minutes before I could start it again, but once it did, it was fine.

It has only been two months so far but none of the things mentioned above have happened since the dealership visit in December. I still use Jscan at least once a week and always for any drive over 100 miles just to keep an eye on it but the misfire count shown by the app has dropped drastically. Last Saturday I drove down to Fort Worth and back which was 366 miles round trip. Going down Jscan showed 35 misfires and coming back it recorded 29 across all cylinders. For me at least, the relearn that ShadowsPapa told me about seems to have fixed my engine problems.

 

[Hootbro]

had a little misfire issues in the beginning of the fall, got the update from dealer, misfire stopped happening ( I heard it just allows the computer to record the misfires better). now every other start up, cold or from ESS the engine misfires and shakes. I shut it off and turn it back on and it clears itself. No check engine light, is it still recording the misfires? When i originally went to dealer they said there are no codes in the computer and they cant do anything unless it happens at the dealer

The PCM still records the misfire count for each cylinder during that ignition run cycle but will dump that info after the next ignition cycle. Need a scan tool like Jscan or similar and you can see what the total per cylinder misfire count is in real time.

Depending on the PCM software algorithm and the actual misfire count parameters, it may have a pending code that needs a second ignition and similar misfire event to post the CEL with a hard misfire OBDII code. If the second ignition event does not meet the parameters for posting a hard CEL code, then it resets and starts over. So, your dealers is somewhat correct in that they have nothing actionable unless the CEL stays posted and hard misfire OBDII codes are present and then they have freeze frame data to go off of.

 

[ShadowsPapa]

had a little misfire issues in the beginning of the fall, got the update from dealer, misfire stopped happening ( I heard it just allows the computer to record the misfires better).

That's the internet scuttle - but not entirely accurate - and there are several TSBs and flashes out there so you'd have to say "which one".

A deep scan may show past misfires that didn't trigger the MIL or set an error. But it seems they often ignore some misfires, too.
I've found that "looking for codes" with software may show nothing but then a "deep scan" or analysis shows issues.

My wife's 2021 GC bucked like a bronc with a burr under the saddle - no light, nothing stored - it was "transient" so you had to do a deep scan to find the codes, non-permanent. A dealership I took it do found no stored codes. Luckily I had recorded the whole series of events in AlfaOBD, captured the misfires and gathered multiple freeze-frames and printed it all for them.
With that they found a TSB that was about misfires caused by SPARK PLUGS. They swapped out the spark plugs and it lived happily ever-after.
Misfires on my 2022 JT were caused by the cam/crank difference not being learned by the PCM. They forced a learn and gathered information and shortly after that a TSB was issued with the final fix. No misfires since.
Hootbro, as usual, has described it well....... you need to capture the events as they happen with a tool like JSCAN or AlfaOBD - there are other FREE software packages that can capture that type of data, too, if that's all you want to do. The software that came with my OBDII BT adapter is pretty nice in that respect. Can't make changes but is really good at catching data and getting freeze frames and such.
You have a transient misfire like my wife's GC had. So it's going to be tough for a dealership to catch. It may be a case of - if it only does it when you first start it - then you may have to leave it with them.
That's how my JT misfire worked - it ONLY did it when hot, parked for a while, then restarted while still warm. With the details, they duplicated the conditions and got it to misfire.

 

[Brojave22]

That's the internet scuttle - but not entirely accurate - and there are several TSBs and flashes out there so you'd have to say "which one".

A deep scan may show past misfires that didn't trigger the MIL or set an error. But it seems they often ignore some misfires, too.
I've found that "looking for codes" with software may show nothing but then a "deep scan" or analysis shows issues.

My wife's 2021 GC bucked like a bronc with a burr under the saddle - no light, nothing stored - it was "transient" so you had to do a deep scan to find the codes, non-permanent. A dealership I took it do found no stored codes. Luckily I had recorded the whole series of events in AlfaOBD, captured the misfires and gathered multiple freeze-frames and printed it all for them.
With that they found a TSB that was about misfires caused by SPARK PLUGS. They swapped out the spark plugs and it lived happily ever-after.
Misfires on my 2022 JT were caused by the cam/crank difference not being learned by the PCM. They forced a learn and gathered information and shortly after that a TSB was issued with the final fix. No misfires since.
Hootbro, as usual, has described it well....... you need to capture the events as they happen with a tool like JSCAN or AlfaOBD - there are other FREE software packages that can capture that type of data, too, if that's all you want to do. The software that came with my OBDII BT adapter is pretty nice in that respect. Can't make changes but is really good at catching data and getting freeze frames and such.
You have a transient misfire like my wife's GC had. So it's going to be tough for a dealership to catch. It may be a case of - if it only does it when you first start it - then you may have to leave it with them.
That's how my JT misfire worked - it ONLY did it when hot, parked for a while, then restarted while still warm. With the details, they duplicated the conditions and got it to misfire.

gotcha I have Jscan, I will plug it in and see if i can figure out how to capture it, thanks

 

[Brojave22]

That's the internet scuttle - but not entirely accurate - and there are several TSBs and flashes out there so you'd have to say "which one".

A deep scan may show past misfires that didn't trigger the MIL or set an error. But it seems they often ignore some misfires, too.
I've found that "looking for codes" with software may show nothing but then a "deep scan" or analysis shows issues.

My wife's 2021 GC bucked like a bronc with a burr under the saddle - no light, nothing stored - it was "transient" so you had to do a deep scan to find the codes, non-permanent. A dealership I took it do found no stored codes. Luckily I had recorded the whole series of events in AlfaOBD, captured the misfires and gathered multiple freeze-frames and printed it all for them.
With that they found a TSB that was about misfires caused by SPARK PLUGS. They swapped out the spark plugs and it lived happily ever-after.
Misfires on my 2022 JT were caused by the cam/crank difference not being learned by the PCM. They forced a learn and gathered information and shortly after that a TSB was issued with the final fix. No misfires since.
Hootbro, as usual, has described it well....... you need to capture the events as they happen with a tool like JSCAN or AlfaOBD - there are other FREE software packages that can capture that type of data, too, if that's all you want to do. The software that came with my OBDII BT adapter is pretty nice in that respect. Can't make changes but is really good at catching data and getting freeze frames and such.
You have a transient misfire like my wife's GC had. So it's going to be tough for a dealership to catch. It may be a case of - if it only does it when you first start it - then you may have to leave it with them.
That's how my JT misfire worked - it ONLY did it when hot, parked for a while, then restarted while still warm. With the details, they duplicated the conditions and got it to misfire.

I used the Jscan a few times, on initial start up and ride down the block ( a mile maybe), cylinder 5 has 35-40 misfires while the others have 1 or 2. then as I drive for longer cylinder 5 misfires stops and the others will be pretty even on misfires under 5 total for 10 miles or so. leaning towards spark plug issue? what do you think?

 

[Lost1wing]

Hard to tell. Do a compression test on it when it is cold and again when it it warm. Swap plugs when you put it back together. If you can't do that, just swap the plugs.

 

[Hootbro]

I used the Jscan a few times, on initial start up and ride down the block ( a mile maybe), cylinder 5 has 35-40 misfires while the others have 1 or 2. then as I drive for longer cylinder 5 misfires stops and the others will be pretty even on misfires under 5 total for 10 miles or so. leaning towards spark plug issue? what do you think?

On my third Gladiator and from what I have observed with Jscan and counting misfires, at least one cylinder like yours seems to have the same issue of a misfire count being double digit while the others are single digit.

I chased this rabbit on my 2020 that had a #4 cylinder high count misfire at a cold engine startup of like 25-35 and did the same thing of creeping up on my 36 mile work commute before leveling off. I swapped fuel injectors and coil positions and also all new spark plugs. Even did a compression and pressured coolant leak test with no issues noted. Changed the PCV also. Still would show that high cold start misfire count on #3. Only thing that would temporarily relieve it for a few days was a Seafoam intake cleaning.

My 2021 had the issue on #1 cylinder and my current 2022 has it on the #5 cylinder. At this point, unless I have a CEL for a misfire, I am not losing sleep over this.

I think that is part of the reason for some of the PCM update service bulletins and recalls has been Jeep playing with the misfire count margins to mask this quirk. Misfires due to actual mechanical wear like the lifters and cams is a separate issue.

 

[Brojave22]

On my third Gladiator and from what I have observed with Jscan and counting misfires, at least one cylinder like yours seems to have the same issue of a misfire count being double digit while the others are single digit.

I chased this rabbit on my 2020 that had a #4 cylinder high count misfire at a cold engine startup of like 25-35 and did the same thing of creeping up on my 36 mile work commute before leveling off. I swapped fuel injectors and coil positions and also all new spark plugs. Even did a compression and pressured coolant leak test with no issues noted. Changed the PCV also. Still would show that high cold start misfire count on #3. Only thing that would temporarily relieve it for a few days was a Seafoam intake cleaning.

My 2021 had the issue on #1 cylinder and my current 2022 has it on the #5 cylinder. At this point, unless I have a CEL for a misfire, I am not losing sleep over this.

I think that is part of the reason for some of the PCM update service bulletins and recalls has been Jeep playing with the misfire count margins to mask this quirk. Misfires due to actual mechanical wear like the lifters and cams is a separate issue.

Thanks for the info, I'm just anxious of being stuck on the beach or miles away from home, I have an oil change coming up, going to schedule a appt around then just wanted some info so the dealer doesn't just say can reproduce it sorry come back another time

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