Trying to gather info to find commonality on "misfires"

[Hootbro]

What is your current miles on the truck?

31800 Miles (51K KM)

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[stew7710]

H

You got the basic gist of it.

Right behind the throttle body on the 3.6L intake is a small right angle vacuum hose. At engine idle, remove the hose and with a piece of small hose attached to the intake nipple, just very slowly sip small amount of the Sea Foam being careful to not stall it. Turn off engine, then let soak 15-20 minutes and then take it for a rip down the road. You will fog the neighborhood for a few minutes though.

Have you tried the Seafoam in the oil treatment?

 

[Hootbro]

H



Have you tried the Seafoam in the oil treatment?

No, just intake and in the fuel.

I do 5K mile oil changes and an oil analysis ever 10K miles roughly. I do not want any oil treatment screwing with my oil analysis results.

 

[Jeyz]

This is strictly for information gathering - wondering if ANY of the misfire cases have something in common.
Not all misfires or rough running will be the same causes, but some MAY share the same cause.

Of the engines with the mystery misfire, the MIL (malfunction indicator light) coming on, uneven running (and this only applies to the 3.6 with non-ignition related misfires) - has anyone here had to add coolant to their truck AT ALL, ever? For example, mine was manufactured November 2019. It has never been low on coolant and coolant has never been added.
~ It should not be required under normal conditions in a vehicle this new. ~

If you have added coolant, how much was required? (no matter how little or how much)
Have you added it more than once?

At this point it's only about coolant, nothing else.

I posted on the thread about the engine noise (keys rattling) and just had the TSB done on my truck...after picking it up we heard the noise leaving the dealership, then I started to notice the smell of coolant over the next day or two, then took it back and they said it was a loose hose clamp they needed to tighten which shouldn't take but 15 minutes....6 hours later my truck was ready and it had a new water pump...before all this ever happened, i had noticed my coolant level was low and topped it off on several occasions but never smelt coolant (until after TSB was done)

 

[4S50]

i am adding about 4oz. of coolant every 5k miles and just developed a misfire at startup that is triggering a cel. 122k miles.

 

[ShadowsPapa]

i am adding about 4oz. of coolant every 5k miles and just developed a misfire at startup that is triggering a cel. 122k miles.

I'm at 17,500 miles and still at the level I marked it at back in July of 2022.
In other words, no coolant added in a year and a half and over 17,000 miles.
It's not normal for these to require regular additions of coolant. Some, yes, after time and miles, and it's going to be more frequently in really hot and high altitude climates and locations, but no way at the frequencies many are reporting. it's just not normal.
There's no place for it to go other than the air that's expelled if the cooling system exceeds about 16 psi - and that would take a heap of cycles to drop even a couple of ounces that way.

 

[Maximus Gladius]

i am adding about 4oz. of coolant every 5k miles and just developed a misfire at startup that is triggering a cel. 122k miles.

(21 JTR) My first engine was consuming 1 ounce/1000 kms. My oil analyses all showed “trace” amounts in the oil from the first oil change I did at 1000kms to the last one at 32k kms. Misfires then started at 16k kms. The engine had issues and I had it replaced.

43k kms on the second engine,…no coolant consumption or misfires. Oil analysis still showing iron levels are a bit too high for my liking but runs and sounds great.

I would suggest getting your oil analysis kit from blackstone labs and send in an oil sample to them or try Polaris labs and get a report on the condition of the wear metals and possible coolant consumption. Good data to show the dealership.

Others here have reported long wait times at Blackstone to get reports back. Try Polaris and see what there time line is like to get a report.

 

[ShadowsPapa]

(21 JTR) My first engine was consuming 1 ounce/1000 kms. My oil analyses all showed “trace” amounts in the oil from the first oil change I did at 1000kms to the last one at 32k kms. Misfires then started at 16k kms. The engine had issues and I had it replaced.

43k kms on the second engine,…no coolant consumption or misfires. Oil analysis still showing iron levels are a bit too high for my liking but runs and sounds great.

I would suggest getting your oil analysis kit from blackstone labs and send in an oil sample to them or try Polaris labs and get a report on the condition of the wear metals and possible coolant consumption. Good data to show the dealership.

Others here have reported long wait times at Blackstone to get reports back. Try Polaris and see what there time line is like to get a report.

If you can't see a visible leak or signs of an external leak, and there's no tell in the exhaust, about the only way to know if it's an internal issue is with oil samples - and perhaps even the sniff test of the cooling system (I believe someone here did that - a large "dropper" type device with a special fluid pulls air out of the cooling system and if there's traces of combustion gas in the cooling system, the solution changes color - we used to do that a lot, pretty common tool for our shop back then)
Frankly, if I was suspect of actual coolant consumption, I'd do both - oil sample and test for combustion gas in the cooling system.
You can often "borrow" such a tool at a parts store if you pay for the fluid used.
Or you can buy it and own it at many auto parts stores, NAPA is one that has them around here.
We used these back in the 70s.

My reasoning for using both test methods (sample and gas) is that you can have a leak that produces combustion gases in the cooling system but doesn't necessarily contaminate the oil to the point of sending off an alarm. Some "cracks" or head gasket defects can result in a "leak" where it requires hundreds of pounds of pressure to breach the defect, but the 16 psi of a cooling system doesn't force enough coolant into a chamber to be "tracked" into the oil. A crack around an exhaust valve seat can result in coolant making its way out of the engine, but not in any large quantity into the oil.

AND - you get instant results........ no waiting for a sample.
I still agree an oil sample is wise. There are many ways for coolant to leave a system through the engine.

Both are so easy it's silly to not get things tested.

I can also see some dealerships thumbing their noses at oil sample results - count on it. It's proof to you, me and most others, but they'll find some other explanation or excuse, show them the blue fluid turning yellow before their eyes, that's different - proof of a breach.
some dealers will listen to reason - and oil samples, some will balk.
Ran into that when I showed them a GPOP from FCA to dealers talking of 4xe transmission leaks. They kept insisting it wasn't for OUR Jeep and we had a "different transmission" and even though I showed them all of the comments from Wrangler 4xe forums - with the 4xe logo and the people clearly talking of their 4xe WRANGLER, they still said I was looking at the wrong transmission. (that's when I got rather pissy and insisted on talking to the boss in person)
So I have a feeling - around here an oil analysis would only convince me - not them.

 

[4S50]

i am adding about 4oz. of coolant every 5k miles and just developed a misfire at startup that is triggering a cel. 122k miles.

My start up misfire has went away since I started using a battery tender. I pulled the battery (I am only running one) and tested it and it returned fine, but when I start without keeping it on the battery tender for a couple of days I get a red alert on the dash that I am guessing is low voltage. The dash screen momentarily shows 13.3-13.5 volts then moves up to 14.5-6 as the alternator kicks in, I am guessing.
I have also been trying to figure out where my coolant is going as it appears unrelated to the misfire. I used a combustion gas checker and there was no detection of combustion gas in the coolant system. I have sent an oil sample out to Blackstone and am awaiting a response.
Any thoughts on what else I can look at?

 

[Maximus Gladius]

My start up misfire has went away since I started using a battery tender. I pulled the battery (I am only running one) and tested it and it returned fine, but when I start without keeping it on the battery tender for a couple of days I get a red alert on the dash that I am guessing is low voltage. The dash screen momentarily shows 13.3-13.5 volts then moves up to 14.5-6 as the alternator kicks in, I am guessing.
I have also been trying to figure out where my coolant is going as it appears unrelated to the misfire. I used a combustion gas checker and there was no detection of combustion gas in the coolant system. I have sent an oil sample out to Blackstone and am awaiting a response.
Any thoughts on what else I can look at?

Sounds like part of that is what I experienced on my first engine (21 JTR) I was consuming 1ounce/1k kms. The tech did that combustion gas test a couple of times, 2 different dealerships and non was detected but all my lab reports indicated “trace” glycol in the oil. 6 oil changes and analyses in 32k kms.

Chrysler wanted me to sign financial responsibility to investigate the internal leak but I had zero confidence the technicians would find anything and I didn’t know they knew how to tear down engines.

One thing led to another and my insurance company paid for a new engine

 

[Alpine Warthog]

45K miles, oil change a week ago. Started the Jeep after church and saw some pretty thick white smoke come out the pipe. Definitely some smell too.... I'm all, don't worry about it, you're being paranoid, its only at 45K miles and you're only looking for an excuse....
Popped the hood today, to check things out and Yup....Coolant is under an inch in the reservoir....

Called the dealership, asked if they could confirm the tech noted checking the coolant. They confirmed they had. I said, then I need to make an appointment, because I'm down to an inch of coolant in the rez and I'm seeing smoke..

On another note, I've been hearing a tick that comes and goes and it doesn't seem to matter if it's hot or cold. Sounds almost like a diesel some days.

Very glad I've got some warranty.....

 

[Banned]

May 2021 Build; Mojave 3.6, automatic
1,200 Miles

Not sure if mine is transmission programming related or engine related: During the first thousand miles, I have experienced a surging or slight 'bucking' sensation that seems like a misfire or the programming seems off.

Examples:
1. Sometimes simply rolling with no pedal input, at near idle RPMs through the neighborhood and there is a subtle bucking or pulsation like the transmission doesn't know what gear to be in.
2. Pulling through 3000-4500, partial throttle it feels like engine timing is fluctuating, something is misfiring or bad fuel type of pulsation sensations - not a smooth acceleration until higher RPMs.
3. 50% throttle, engine seems to struggle to rev, like it has constipation, gets to 4500 rpm and suddenly pops/snaps and comes alive - like something was constraining.

I've tried a different set of wheels and tires from an Overland, reducing unsprung weight by 125lbs. I think this may have amplified the sensations. I took it to the dealer, they thought the wheel tire setup may have been messing with the ECU but it's off by less than 1 mph when compared to Waze. They scanned for codes and did not find any. I put the Mojave stock wheels back on, drove 100 miles or so and its still randomly doing the issue.

Is there a data logging software that I could use to try and capture if its engine or transmission related?

Low Speed Surge or Lurch. Sounds almost like what mine are doing.

 

[4S50]

45K miles, oil change a week ago. Started the Jeep after church and saw some pretty thick white smoke come out the pipe. Definitely some smell too.... I'm all, don't worry about it, you're being paranoid, its only at 45K miles and you're only looking for an excuse....
Popped the hood today, to check things out and Yup....Coolant is under an inch in the reservoir....

Called the dealership, asked if they could confirm the tech noted checking the coolant. They confirmed they had. I said, then I need to make an appointment, because I'm down to an inch of coolant in the rez and I'm seeing smoke..

On another note, I've been hearing a tick that comes and goes and it doesn't seem to matter if it's hot or cold. Sounds almost like a diesel some days.

Very glad I've got some warranty.....

Sounds like what I am experiencing. Jeep dealers solution is to change the engine.

 

[Alpine Warthog]

Sounds like what I am experiencing. Jeep dealers solution is to change the engine.

Whoa.................. Thats a bit extreme. But hey, a new motor under warranty? Not the worse outcome I guess.

 

[4S50]

The tech diagnosed that coolant is getting in the combustion chamber. Rather than diagnose further and repair, the modern solution appears to be just throw it away and put in a new one.

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