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Old 02-17-2017, 11:49 AM   #1
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Rough idle & check engine light

Did a search and couldn't find an exact match so here is my question.

Our '15 Willys started idling rough when we started it the other day. Felt like bad fuel idle to me although we were half way through a full tank. Ran fine at anything but idle.

Later the check engine light came on. So we looked in the manual and one of the causes was bad fuel and it might clear after a couple of normal driving runs. We put in dry gas and topped up with rec90 no ethanol fuel. Started to idle OK that day.

Today I started it up and no CEL. Should I bother to have the code read. I don't have an OBD but might be able to borrow one or take it to a dealer or auto shop.
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Old 02-17-2017, 12:08 PM   #2
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go buy one they are a dime a dozen now for $50. If you have a android phone you can get the torque app and a OBD2 bluetooth sensor and even have real time monitoring.

either leave it or if your nervous, go to the dealer as you are under warranty. They might charge you 50$ to read the code though.

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Old 02-17-2017, 12:31 PM   #3
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You can pull codes without a reader. I think the trick is to turn the key to the on position without starting it. You need to do it three times in rapid succession.

Then there are cheap ELM327 devices for ~$25. Get a WiFi one if you have an iPhone and the Bluetooth version works with other phones. You will need an app to pull the codes. Torque is like $5.
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Old 02-17-2017, 03:09 PM   #4
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Check with your dealer. There was/is and extended warranty on the left side cylinder heads. The valve guides work themselves loose and cause a mis/rough running. The factory fix is to replace the cylinder head.
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Old 02-17-2017, 03:56 PM   #5
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Hmmm $50 for a dealer to read a code and I can get an Bluetooth OBD2 reader for $12? Ordered one from Amazon. Thanks for the help. I should be able to use it on most of our vehicles.

Is the Torque app worth the tiny $5 price or is there a freebie that is useful?
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Old 02-17-2017, 05:45 PM   #6
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Quote:
Originally Posted by HD4Mark View Post
Hmmm $50 for a dealer to read a code and I can get an Bluetooth OBD2 reader for $12? Ordered one from Amazon. Thanks for the help. I should be able to use it on most of our vehicles.

Is the Torque app worth the tiny $5 price or is there a freebie that is useful?
get the torque pro...you can do live monitoring coolant temps/transmission temps/battery voltages, etc...
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Old 02-17-2017, 05:49 PM   #7
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Quote:
Originally Posted by nighowl2000 View Post

get the torque pro...you can do live monitoring coolant temps/transmission temps/battery voltages, etc...
Example of my setup

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Old 02-18-2017, 07:33 AM   #8
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get the torque pro...you can do live monitoring coolant temps/transmission temps/battery voltages, etc...
Looks way cool. Does it have to be set up differently every time if you use it on a second vehicle? It's really my wife's Jeep so it might be worth getting the app for her phone and also for mine.
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Old 02-18-2017, 03:03 PM   #9
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Looks way cool. Does it have to be set up differently every time if you use it on a second vehicle? It's really my wife's Jeep so it might be worth getting the app for her phone and also for mine.
No. You can have profiles. I have one for my JKU and one for my wifes commander.
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Old 02-21-2017, 07:03 AM   #10
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No. You can have profiles. I have one for my JKU and one for my wifes commander.
Excellent! The ELM 327 should be in the mailbox today.
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Old 02-21-2017, 01:45 PM   #11
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Got the ELM327 and set it up with the free OBD car doctor app. Getting torque next.

Error code was P300, engine misfire no specific cylinder(s). CEL light still out and no further problems. Was a breeze to set up. SO next will be to download Torque and play with that.

Does everyone just leave it installed under the dash or disconnect it?
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Old 02-21-2017, 02:23 PM   #12
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Quote:
Originally Posted by HD4Mark View Post
Got the ELM327 and set it up with the free OBD car doctor app. Getting torque next.

Error code was P300, engine misfire no specific cylinder(s). CEL light still out and no further problems. Was a breeze to set up. SO next will be to download Torque and play with that.

Does everyone just leave it installed under the dash or disconnect it?
I leave mine connected. No issues.

This is how you display transmission temp:

http://www.300cforums.com/forums/tec...ge=1&_k=3oykpn
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Old 02-21-2017, 05:26 PM   #13
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I leave it installed as well. My current JKU is an Auto trans, but my previous was a manual and I couldn't leave it in because my leg hit it every time I pushed the clutch in


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Old 02-21-2017, 05:59 PM   #14
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Get an extension cable for the obd port. Make sure its a flat one. They are like $10 bucks on amazon. I have a manual so i was always knocking the bluetooth adapter loose. With extension cable, now its wedged behind the dash and out of the way. Cant tell its there. I use the tourqe pro app and its awesome. I have a dash mounted 10" tablet. Here is what it looks like. I love how i can monitor everything thats going with the turbo.
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Old 02-22-2017, 09:11 AM   #15
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Ours is an automatic and after a few times in and out have not knocked it loose. I would have bought a standard but it's our RV tow vehicle and my wife's daily driver so I caved on the stick. She can drive one, just doesn't want to. I have to admit after driving standards for forty plus years they can be a PIA if you are stuck in traffic.

I mostly got started on this, with the help of everyone here, just to pull codes not so much for real time monitoring. It is cool though and I'm sure we will play with it.

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