2014 3.6 cyl 1 missing - JeepForum.com
 
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post #1 of 14 Old 09-29-2021, 04:11 PM Thread Starter
KeepOnTruckin
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2014 3.6 cyl 1 missing

Folks,


My 2014 WK2, 125k miles, 3.6, cylinder 1 has been skipping badly for about a month. The CEL has gone off on its own a couple of times, but has been mostly on.



My mechanic changed the spark plug and coil, then the fuel injector, and no change. (He did put the old parts back and didn't charge me for them.) He says the compression shows well within specs. He's stumped.


Anybody have any ideas? Thanks.


KoT

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post #2 of 14 Old 09-29-2021, 05:08 PM
ColdCase
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Was fuel pressure checked?

Anything that affects the speed of the crankshaft can cause the DTC, but you say you can hear/feel the misfire and it doesn't always set a DTC.

When a Misfire is detected for a particular cylinder, the PCM will shut down that cylinder's Injector Control circuit.

You could have a lazy/intermittent lifter. Does the misfire change with an oil change?

One could capture some live data and look at it to see whats going on.

Something in general could be off causing marginal operation, and cylinder 1 could be he weakest cylinder and a misfire shows up there first. So anything that causes poor performance, vacuum leak, pad sensors, bad VVT phasers... low oil pressure...

I just got lost in thought. It was unfamiliar territory;
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post #3 of 14 Old 09-29-2021, 08:25 PM
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I just finished a repair on a 15 Journey today that did not set a DTC but did run rough and also had valve train noise. The left bank exhaust cam had one of the lobes completely worn off and the lobe next to it starting to wear badly. A couple of other rockers throughout the engine had loose roller bearings.

If you cannot fix it with a hammer then it has to be an electrical problem.
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post #4 of 14 Old 09-29-2021, 09:41 PM Thread Starter
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Quote:
Originally Posted by ColdCase View Post
Was fuel pressure checked?

Anything that affects the speed of the crankshaft can cause the DTC, but you say you can hear/feel the misfire and it doesn't always set a DTC.

When a Misfire is detected for a particular cylinder, the PCM will shut down that cylinder's Injector Control circuit.

You could have a lazy/intermittent lifter. Does the misfire change with an oil change?

One could capture some live data and look at it to see whats going on.

Something in general could be off causing marginal operation, and cylinder 1 could be he weakest cylinder and a misfire shows up there first. So anything that causes poor performance, vacuum leak, pad sensors, bad VVT phasers... low oil pressure...

I had checked the codes with a cheapo reader. The first time it came on it was a p0301/cylinder 1 misfire. I reset it. It came back a week or so later. It had, of course, continued to run rough--most noticeable at idle and light acceleration. Frankly, I was surprised at how long it took to come back on, but by the time I got around to taking to a mechanic, it went off on its own, although it was still was running crappy.


So I brought it the mechanic, who checked it out with a fancy snap-on tool that looked like a big tablet. He shoed me what seemed to be a listing of what all six cylinders were doing. One screen I think he said said was showing mis-fires, and cyl. 1 was bouncing around the 100 range, with cyl. 3 bouncing around the low single digits, with the other cylinders I think showing mostly 0 or 1, maybe 2 occasionally.



I think he assumed it was going to be an easy fix, and seemed surprised that it wasn't. Is it time for a dealer?



Re: oil changes--I'm 2500 into my previous oil change, and the issue is fairly new. It runs fine when going steady on the highway, and the mileage on longer rides hasn't suffered. But it is pretty lousy around town.



Thanks.
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post #5 of 14 Old 09-29-2021, 10:36 PM
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Quote:
Originally Posted by Boojo35 View Post
I just finished a repair on a 15 Journey today that did not set a DTC but did run rough and also had valve train noise. The left bank exhaust cam had one of the lobes completely worn off and the lobe next to it starting to wear badly. A couple of other rockers throughout the engine had loose roller bearings.
I didn't want to go there, but that is a likely scenario. I forget, but wouldn't a compression test show some kind of anomaly?

I just got lost in thought. It was unfamiliar territory;
Current: 2011 Grand Cherokee Overland V8, 2009 Liberty Rocky Mt V6
Previous: 2000 Grand Cherokee Laredo I6, 1979 CJ7 I6 Quadratrac
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post #6 of 14 Old 09-30-2021, 06:09 AM
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Quote:
Originally Posted by ColdCase View Post
I didn't want to go there, but that is a likely scenario. I forget, but wouldn't a compression test show some kind of anomaly?
A static test may not, a dynamic test probably would but the only bank you can really dynamic test is the left bank. You have to remove the intake to pull the right bank plugs.

If you cannot fix it with a hammer then it has to be an electrical problem.
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post #7 of 14 Old 09-30-2021, 05:46 PM Thread Starter
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Quote:
Originally Posted by ColdCase View Post
I didn't want to go there, but that is a likely scenario. I forget, but wouldn't a compression test show some kind of anomaly?

So . . .



Any new thoughts? As my mechanic seems stumped, and I can't seem to find another one that I have faith in, am I on to a dealer, and hoping that they know what they're doing and don't gouge me too bad?


Thanks again.


KoT
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post #8 of 14 Old 09-30-2021, 07:56 PM
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A dealership is the place that will know the most about your vehicle.

If you cannot fix it with a hammer then it has to be an electrical problem.
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post #9 of 14 Old 10-01-2021, 08:12 AM
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Why not have your mechanic pull the valve covers and inspect the cams? One side is fairly easy to do, the other side (cylinders 1, 3, 5) a little more work but it will answer the questions about possible cam/rocker issues.
If the cams check out ok, have the mechanic swap the #1 coil and plug with another cylinder while the intake is still off. Then see if the DTC stays with cylinder 1 or if it moves the other cylinder. That will verify the new coil and plug are good or not.

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post #10 of 14 Old 10-01-2021, 11:23 AM
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[quote=Nejeep;41365461]Why not have your mechanic pull the valve covers and inspect the cams? One side is fairly easy to do, the other side (cylinders 1, 3, 5) a little more work but it will answer the questions about possible cam/rocker issues.
If the cams check out ok, have the mechanic swap the #1 coil and plug with another cylinder while the intake is still off. Then see if the DTC stays with cylinder 1 or if it moves the other cylinder. That will verify the new coil and plug are good or not.[/quote @ColdCase you're like the god of this forum it's fantastic every thread I just look for your reply and there's the answer how long have you been a chrysler tech?

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post #11 of 14 Old 10-03-2021, 11:57 AM
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Quote:
Originally Posted by ColdCase View Post
I didn't want to go there, but that is a likely scenario. I forget, but wouldn't a compression test show some kind of anomaly?

would not because the rocker(s) being bad and/or the cam lobes eroding would just not open the valves as much therefore you would still have a seal for the comp test AND leakdown test for that matter.

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post #12 of 14 Old 10-03-2021, 12:12 PM
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Yeah, that makes sense, thanks. I may have been thinking that valve guide/seat head defect early 3.6s had. So it may be pull the valve covers and inspect the cams time.

There are independent shop techs that are familiar enough with this common engine, and the cam/lifter issue is not all that rare in just about any engine now days. But a dealer may be best equipped to deal with it.

I just got lost in thought. It was unfamiliar territory;
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post #13 of 14 Old 10-04-2021, 08:50 AM
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Quote:
Originally Posted by RedTrex View Post
would not because the rocker(s) being bad and/or the cam lobes eroding would just not open the valves as much therefore you would still have a seal for the comp test AND leakdown test for that matter.
This is why I said a dynamic compression test earlier. It is done engine running and it shows flow issues. It really works. The down side is it really can only be done on the left bank of the 3.6L unless you can get a compression tester on the right and still have the intake plenum bolted on. I do not think you can.

If you cannot fix it with a hammer then it has to be an electrical problem.
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post #14 of 14 Old 10-18-2021, 05:52 AM Thread Starter
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Quote:
Originally Posted by KeepOnTruckin View Post
Folks,


My 2014 WK2, 125k miles, 3.6, cylinder 1 has been skipping badly for about a month. The CEL has gone off on its own a couple of times, but has been mostly on.



My mechanic changed the spark plug and coil, then the fuel injector, and no change. (He did put the old parts back and didn't charge me for them.) He says the compression shows well within specs. He's stumped.


Anybody have any ideas? Thanks.


KoT

Dealer found one of the rocker bearings was bad, and $1,100- all fixed. They changed all the rockers on that side while it was open. Said the cams were fine.


$225- for parts, small amount for "environmental" and the rest was labor.


The spent almost two hours at $125- per hour diagnosing what we already know, although they also reamed out the injector. On the other hand my mechanic only charged me $40- for it, and I can't blame them for needing to confirm.Could have been much worse, I suppose.

He had said before they opened it up that it was a camshaft issue about 1/3 of the time.
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