Survey- For those with misfire issues

[mortuar]

Seriously, You mean they couldn't ask the tech even for what he remembered? That's almost laughable. When I do such work it sticks in my mind if there's a variation over 10% or not - and at least which cylinders had the lowest even if I can't recall if it was 145 or 147.
So they do a test and don't log it or write it down.

Just my gut, my opinion, my feeling, but your accounting of them doesn't give me great confidence............

I'm hoping the service advisor means he just forgot what he was told - I imagine the tech wrote it all down... right? I mean, I can't imagine they can escalate something like this without data. I'll keep everybody posted. D:

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[ShadowsPapa]

I hope you are right - and good luck, seriously.

 

[mortuar]

Welp, didn't receive a callback last night. Let's see what they say today after the leak down test. I'll try to get the compression numbers from them... again. lol

 

[mortuar]

I just received a text message with a video from the technician showing my truck running in the background. Tech states he drove the truck all day yesterday and left it overnight to check for a rough idle on a cold start, couldn't replicate. Said there is nothing they can do at this point because they can't get it to fire the check engine light again.

This is after the service advisor told me last night they did a compression check and moved on to a full leak down test.... I guess I'll have to pick it back up and drop it back off when the code fires again. Oye.

 

[ShadowsPapa]

I just received a text message with a video from the technician showing my truck running in the background. Tech states he drove the truck all day yesterday and left it overnight to check for a rough idle on a cold start, couldn't replicate. Said there is nothing they can do at this point because they can't get it to fire the check engine light again.

This is after the service advisor told me last night they did a compression check and moved on to a full leak down test.... I guess I'll have to pick it back up and drop it back off when the code fires again. Oye.

Seriously - they did a compression check AND a leak-down test and then decided nothing was wrong?
Apparently all cylinders were within 10% of each other? (modern engines this new should be closer than that, IMO) Anything even close to 10% difference high to low should have given them pause - and to spend the TIME (money for them) to do all that - and then nothing? Makes me wonder why they did both...... if they thought nothing was wrong. Weird.

I'd love to see the results of both tests.

 

[mortuar]

Seriously - they did a compression check AND a leak-down test and then decided nothing was wrong?
Apparently all cylinders were within 10% of each other? (modern engines this new should be closer than that, IMO) Anything even close to 10% difference high to low should have given them pause - and to spend the TIME (money for them) to do all that - and then nothing? Makes me wonder why they did both...... if they thought nothing was wrong. Weird.

I'd love to see the results of both tests.

I hear you. It makes no sense. I'm waiting for a callback from my service advisor as well so I can ask him for all of the data from both the compression and leak down test.

The last time I brought it in, they told me they drove it, and there wasn't a single mile extra on the truck. I honestly don't believe they are even paying attention enough for the rough idle - maybe not paying attention at all. It stumbles and shudders every morning when I start it and has been doing that for months now.

 

[ShadowsPapa]

I hear you. It makes no sense. I'm waiting for a callback from my service advisor as well so I can ask him for all of the data from both the compression and leak down test.

The last time I brought it in, they told me they drove it, and there wasn't a single mile extra on the truck. I honestly don't believe they are even paying attention enough for the rough idle - maybe not paying attention at all. It stumbles and shudders every morning when I start it and has been doing that for months now.

These engines being as smooth as they are normally at idle - I'd expect a person, like a MECHANIC, for example, should notice if it's less than perfect. Mine has a very smooth quiet idle at first start. If it wasn't for the slght exhaust note and the tach, I've even wondered - did I shut this thing off or not?
These are so smooth at idle normally you can even feel the pulses and belt shake of having the AC on if you pay attention.
Your situation just keeps getting weirder and weirder (if that's even a word)

 

[Gijohn96]

Seriously - they did a compression check AND a leak-down test and then decided nothing was wrong?
Apparently all cylinders were within 10% of each other? (modern engines this new should be closer than that, IMO) Anything even close to 10% difference high to low should have given them pause - and to spend the TIME (money for them) to do all that - and then nothing? Makes me wonder why they did both...... if they thought nothing was wrong. Weird.

I'd love to see the results of both tests.

That is exactly what they did with mine. Off by more than 10%, then they decided to put everything back together and install the second PCM flash. That is when the dealership pushed back on the FCA engineers who wanted the engine torn down again.

New engine should arrive in a couple weeks.

 

[ShadowsPapa]

That is exactly what they did with mine. Off by more than 10%, then they decided to put everything back together and install the second PCM flash. That is when the dealership pushed back on the FCA engineers who wanted the engine torn down again.

New engine should arrive in a couple weeks.

MAYBE these dealers need a subscription to PM HAHAHAHA as they obviously fail at engine diagnosis 101
Tell 'em to read this if it's not over their heads -
https://www.popularmechanics.com/cars/how-to/a8520/cars-101-how-to-do-a-compression-test-14912158/

Thank goodness I retired from that stuff and deal with my own shop work now. These guys would drive me nuttier than I already am.

 

[mortuar]

Heading to the dealer in just a little bit to pick it up. I told them to not start it, leave it wherever it is, and give me the keys when I get there to watch me start it. If it doesn't have a rough idle, I'll be amazed. It rough idles every morning I start it.

 

[dgulia]

Good luck and hope it’s all fixed and taken care off for you so you can enjoy it

 

[ShadowsPapa]

Heading to the dealer in just a little bit to pick it up. I told them to not start it, leave it wherever it is, and give me the keys when I get there to watch me start it. If it doesn't have a rough idle, I'll be amazed. It rough idles every morning I start it.

If that's the case your open loop programming is likely screwed up (or a sensor screwed up)

It runs on a default program (open loop) with no input from the O2 sensor until it can get readings and then closes the loop and runs off sensor input only. The O2 sensor has to warm up before it can provide feedback.
The PCM goes by MAP (Manifold Absolute Pressure sensor if equipped) to get barometric pressure, the temperature reading from the coolant temp sensor, and the ambient air temp sensor.
That's one of the things the PCM program is supposed to deal with.
But it also involves operation later - I noted the EGR programming and operation is impacted as well - indicating it is supposed to resolve warm engine operation, too.

The fact yours does it every cold start should be a clue for them. (unless they are clueless, that is)

 

[mortuar]

Just picked it up. Spoke with the service advisor and asked him if he got the compression readings from the tech. "Yeah, he said they were all 124 to 125, no issues. The leak down test showed no issues as well. We cleared the check engine lights and we can't get it to throw any codes again." So I tell them that's fine, it took like 200 miles for it to throw the code again, so I'll just drive it a ton the next few days and see if it throws it again. He also hands me a printout that shows the following from Chrysler/Jeep in regard to the 3.6L engine: "Compression should not be less than 689 kPa (100 psi) and not vary more than *25 percent* from cylinder to cylinder." Yep, Jeep/Chrysler is ok with a 25% variance in compression between cylinders.

Then I get the paperwork. It literally says, "no work done, no parts needed. Returned vehicle to customer." So I ask him why they didn't write up the check engine light being present, what the codes were, what the compression actually was per cylinder, that they actually performed a compression and leak down test. He told me it's because there was no CEL active and they would not be paid for that work - that it would be irrelevant to Chrysler/Jeep. I told them I brought it in with one active CEL code (P0300) and two pending (P0300 and P0304). He said it's irrelevant if they can't get it to throw the check engine light while it's in their possession. So, I ask him why they did the compression test followed by a leak down, and he said, "we just wanted to double check, but we're not getting paid for that work." He also kept saying, "our tech can't deviate from Jeep's playbook in regard to service, so we have done all we can at this point" which I totally understand... I just don't understand why they didn't take literally any notes about what was done.

There was nothing I could do to get the actual figures from the tech for the compression check - he said he didn't write them down. I'm wondering if a compression check/leak down test were even done, honestly. So, I take the service advisor to my truck, and we start it, and it has a very minor rough idle/stumble, but it's there. I let him sit in it. He tells me he can feel it, but that it's, "completely normal for all vehicles with auto start/stop." I told him this was a very mild rough start, but it didn't do this until like 6-7 months into ownership. He told me it's all totally normal. I asked him why it doesn't do this if I start it up after the engine is warmed up. He has no answer.

Is it possible for Jeep/Chrysler to deny this as an attempt to fix the issue if it came down to a lemon law situation? I can't think of any other reason to not be verbose in notes when you're dealing with misfires on a fairly new vehicle. I guess I'll just cross my fingers it doesn't throw anymore codes.

 

[ShadowsPapa]

100 is low IF the valves are opening fully - perhaps the intake valves are on low lift by default, lowering the compression test results. 25% is a wide variation, IMO. Maybe not on an engine with 70,000 miles, but on one with 10K or less?
These are also high compression engines compared to older engines. Used to be for say a 258 100 was low but acceptable if they were fairly even - then the compression ratio was only around 9:1 or less. These are what, 11:1 or close to that?
Keep DETAILED records - in case you need them, Obviously they won't. Wow.
I can begin to feel your frustration even clear up here.

 

[Robicon]

Did you ever submit your build information? I don't see it, but certainly could have overlooked it.

I thought I did but here it is just in case:

Build date: 100219
Mileage when it first occurred: ~2000km
How many times has it occurred: 3
What exact codes did it throw: P0300
Is the issue on going? N
If so, what has been done to try to solve the issue? Software update
Was the issue ever fully resolved? TBD (so far so good!)

3 days of driving it after the software update and still doing ok. No CEL, no ESS errors (knock on wood...)

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