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-   -   Misfiring 2010 JKU (http://www.jeepforum.com/forum/f96/misfiring-2010-jku-1075110/)

Jos360 07-23-2010 05:33 PM

Misfiring 2010 JKU
 
I am posting this to ask if someone else has had the same problems. I don't really think I will find the solution as even the dealership has no clue..

The story:
I have a 2010 JKU, it has 10500 miles on it and I'm the first owner.
2 weeks ago, I was low on gas and noticed the engine starting to run rough. I thought: gas tank empty (although the gage wasn't THAT low...) so I fueled up. It still ran rough (5 cylinders) and the computer gave the P0300 & P0300 code (multiple cilinder misfire).

After about half a mile after fueling up, the car stalled and wouldn't fire up again (or only to about 200rpm and stalling again).

I got a tow to the dealership. They replaced 1 spark plug and the injector for cil.6. The car fired up again and ran good. Drove half a mile and the same problem again.

Now they got it as far as idling perfect and revving up in neutral too, but as soon as you put it in gear and start driving, cil.6 quits working.

Work done so far:
- compression test, everything was OK.
- replaced spark plug (old one was not broken)
- replaced fuel injector (old one was not broken or dirty)
- replaced wiring harness for fuel injectors (advised by Chrysler, these seem to rub against the intake manifold and can cause problems.
- replaced coils and plug leads
- reset the computer

Nothing helped so far. The dealer ordered a brand new ECU now, advised by Chrysler. It takes another week or so to come in so I'm not happy... The dealer has no clue if this will solve the problem, they are just guessing.

Do any of you guys have an idea or recognise this problem?

The only abuse I ever gave my Jeep is Silver Lake sand dunes, where I was about 1 week before the Jeep broke down. The dealer confirmed already that there was no sand in the fuel so that can't be the problem. For the rest I only use the car on-road.

ronjenx 07-23-2010 06:21 PM

There is a long list of possible causes for multiple cylinder misfire.

Ask the service rep if they are going through the step-by-step trouble shooting procedure. From the way you describe what they've done so far, they appear to be throwing parts at it.
A good troubleshooter should be able to flush out the problem.

Here is what the service manual says to check, Each item has specific tasks to verify the condition of the component.

NOTE: Anything that affects the speed of the crankshaft can cause a misfire DTC.

Visual inspection is first:

Turn the ignition off.
- Visually inspect the engine for any of the following conditions.
- Worn serpentine belt
- Binding Engine-Driven accessories: A/C Compressor, P/S Pump, Water pump.
- Misalignment of the Water pump, P/S Pump and A/C Compressor pulleys
- Corroded PCM power and ground circuits.
- Improper CKP, CMP, MAP, and TP Sensor mounting
- Poor connector/terminal to component connection. i.e., CKP sensor, Fuel Injector, Ignition coil, etc.
- Vacuum leaks
- Restricted Air Induction system or Exhaust system.
- Internal engine component failures.

Then, they should test the following items:

(F342) ASD RELAY OUTPUT CIRCUIT

INJECTOR CONTROL CIRCUIT

COIL CONTROL CIRCUIT

IGNITION WIRE

SPARK PLUG

IGNITION COIL

FUEL PUMP INLET STRAINER PLUGGED

RESTRICTED FUEL SUPPLY LINE

FUEL PUMP MODULE

FUEL PRESSURE LEAK DOWN

FUEL INJECTOR

ENGINE MECHANICAL (see below)

POWERTRAIN CONTROL MODULE (PCM)


"Engine Mechanical", mentioned above, includes:

Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications
VALVE SPRINGS - cannot be weak or broken

MacK 07-24-2010 01:13 AM

I had P0306, which is Cylinder 6 misfire. My engine was running rough. I replaced the wires and all 6 spark plugs and haven't had the issue since. I ordered these: MPG Plus Spark Plug Wires by Granatelli and Other Jeep Parts and Jeep Accessories by 4 Wheel Drive Hardware-RH1 with Autolites and I have been perfect ever since.

I even gained some MPG.

Jos360 07-24-2010 12:42 PM

Quote:

Originally Posted by ronjenx (Post 9839953)
There is a long list of possible causes for multiple cylinder misfire.

Ask the service rep if they are going through the step-by-step trouble shooting procedure. From the way you describe what they've done so far, they appear to be throwing parts at it.
A good troubleshooter should be able to flush out the problem.

Here is what the service manual says to check, Each item has specific tasks to verify the condition of the component.

NOTE: Anything that affects the speed of the crankshaft can cause a misfire DTC.

Visual inspection is first:

Turn the ignition off.
- Visually inspect the engine for any of the following conditions.
- Worn serpentine belt
- Binding Engine-Driven accessories: A/C Compressor, P/S Pump, Water pump.
- Misalignment of the Water pump, P/S Pump and A/C Compressor pulleys
- Corroded PCM power and ground circuits.
- Improper CKP, CMP, MAP, and TP Sensor mounting
- Poor connector/terminal to component connection. i.e., CKP sensor, Fuel Injector, Ignition coil, etc.
- Vacuum leaks
- Restricted Air Induction system or Exhaust system.
- Internal engine component failures.

Then, they should test the following items:

(F342) ASD RELAY OUTPUT CIRCUIT

INJECTOR CONTROL CIRCUIT

COIL CONTROL CIRCUIT

IGNITION WIRE

SPARK PLUG

IGNITION COIL

FUEL PUMP INLET STRAINER PLUGGED

RESTRICTED FUEL SUPPLY LINE

FUEL PUMP MODULE

FUEL PRESSURE LEAK DOWN

FUEL INJECTOR

ENGINE MECHANICAL (see below)

POWERTRAIN CONTROL MODULE (PCM)


"Engine Mechanical", mentioned above, includes:

Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications

VALVE SPRINGS - cannot be weak or broken

Thanks man! This helps, I'll print out this post and go over to the dealership. What you said is right, they have no clue what the problem is and they randomly are throwing parts at it. They pulled a JK off the lot and just started exchanging parts... Even though they ordered the ECU now, they still have no clue if that is the problem and if it will solve the problem...

ronjenx 07-24-2010 12:48 PM

Once you challenge their troubleshooting abilities, they may be hard to deal with. So, be as subtle about it as you can.

Lets us know what the say about what they've been doing, and why they weren't going by their own tech data.

kudah 07-24-2010 02:28 PM

they've pretty much gone through that list with the parts they have replaced. Now they are replacing the PCM which is the last thing on the list, and is a good possibility for your issue as the PCM drives both the injectors and the coil.

Jos360 07-27-2010 05:38 PM

Dealer expects to get the computer in tomorrow. We'll see if it's the actual problem...

Meanwhile i've been trying to reach Chrysler for any type of compensation for the 3-week loss of my car. After 2 weeks of calling daily I finally reached someone that can actually make an offer and they offered me the 4-day use of a PT-Cruiser.

Anyone has any better ideas how to file my complaints at Chrysler and how to get better compensation? I have been treated horribly by the customer service. No callbacks, empty promises, hangups on the phone etc etc.

MacK 07-27-2010 05:55 PM

Really? I called them regarding my top and they answer within 5 minutes, and always do their best to help :l

JeffinWesternWA 07-27-2010 06:10 PM

contact the district Zone manager, they typically visit each dealer monthly or so....info should be in owners manual, it used to be...

Jos360 07-27-2010 06:19 PM

@ThomasMack,

Yep, horrible. The person answering the phone at first is nice to speak to. But the case manager is the only one who can actually solve a problem with warranty or rental cars etc. I tried to talk to the case manager every day for 2 weeks and never heard her. They gave me specific times that they would call me back and never did (4 times) and the person answering the phone could never get an answer his/herself.
Until I became really mad at the phone, then immediately they gave me an answer (PT cruiser for 4 days) and said that was the final decision by the case manager, as if she had it on her screen but waited for me to get mad to tell me...
This is only 1 thing, I have more complaints about them...

@JeffinWesternWA
Thanks! That actually sounds like a very good idea! I'll try my best to get his phone number or name!!

AlBALUSHIOMAN 09-04-2011 01:00 AM

Hi there dear
I have the same problem on my 07 rubi

Untill now im not knowing how to fix it
I checked the most thinks that cause misfiring everything is ok

Any help

tavic 09-04-2011 09:48 AM

You could of had gotten some crap gas. Usually the crap floats on top for awhile and once it gets low enough it gets sucked up. Most folks don't think of the filter these days because it rated to be around 150k to be changed.

MacK 09-04-2011 10:06 AM

Read my post. My 07 did this and I replaced the spark plugs.

Jos360 09-04-2011 12:36 PM

Quote:

Originally Posted by tavic (Post 12122455)
You could of had gotten some crap gas. Usually the crap floats on top for awhile and once it gets low enough it gets sucked up. Most folks don't think of the filter these days because it rated to be around 150k to be changed.

Once the dealer replaced my ECU, the problem stopped for approx. 5k miles. Then it happened again.
I took out my fuel tank and fuel pump unit, cleaned the tank and the pump, filled up with fresh gas and some injector cleaner and it never happened again. I reckon that dirt in the fuel system ended up being the problem.


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