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  #1  
Old 08-04-2019, 08:46 AM
DexMan DexMan is offline
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misfire cylinder 7 will not clear

I have a 2011 hybrid 7 with n63 engine. I have 102K miles. right around 101K miles I had a misfire cylinder 7 and the car was driving rough. I changed all 8 plugs and the 8 coils. The car is driving better now, but the check engine light has not went off. I tried clearing it with a CARLY OBD2 and it can not find it. AutoZone said the code is reading pending, confirmed and now permanent. I took the plug and ignition coil for cylinder 7 off and made sure it was seated it properly. The car run fine but the CEL will not turn off. What else should I check?
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  #2  
Old 08-04-2019, 06:55 PM
HerbP HerbP is offline
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Quote:
Originally Posted by DexMan View Post
I have a 2011 hybrid 7 with n63 engine. I have 102K miles. right around 101K miles I had a misfire cylinder 7 and the car was driving rough. I changed all 8 plugs and the 8 coils. The car is driving better now, but the check engine light has not went off. I tried clearing it with a CARLY OBD2 and it can not find it. AutoZone said the code is reading pending, confirmed and now permanent. I took the plug and ignition coil for cylinder 7 off and made sure it was seated it properly. The car run fine but the CEL will not turn off. What else should I check?
Have you tried moving the coil to the next cylinder to see if the problem might follow the coil? If the problem does not change after moving the coil, I would start looking at a dirty fuel injector? If you know someone with ISTA, you can drill down into the module to clear the fault. If the problem was repaired, the fault should clear without a problem. Other things to look at would be a bad ground wire on the COP that grounds to the top of the valve cover, & the wiring that goes to the COP. With excess heat under our hoods, the wiring gets brittle at times.
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Old 08-04-2019, 08:06 PM
DexMan DexMan is offline
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What is COP? What fuel injector cleaner would you recommend? Thank you for your assistance.
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Old 08-05-2019, 06:49 PM
HerbP HerbP is offline
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The COP is the coil pack. You can move the #7 coil to the #6 cylinder, to see if the problem follows the coil. The best fuel injector cleaner I have used is Techron in the black bottle. Shell puts it in their fuel as a supplement, but a bottle every 4 tanks is a good PM to follow.
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Old 08-06-2019, 07:14 PM
DexMan DexMan is offline
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thank you. I purchased 8 new ignition coils and installed them when the problem first started, so I haven't tried moving ignition coils. Do you still think I should switch 6 and 7? I put in a bottle of your recommended injection cleaner. I will update you in a few days to let you know the status. Thanks.
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Old 08-06-2019, 07:17 PM
BabyUnicornTaco BabyUnicornTaco is online now
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If you have a valve cover leak that is allowing oil to enter your spark plug tubes then your issue could be oil contaminating the spark plug on that cylinder. If you remove the ignition coil from 7 and look down the tube you might see some oil. Take a look.


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Old 08-06-2019, 07:49 PM
DexMan DexMan is offline
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good idea. When I checked the cylinder the second time (after noticing the code did not go away), I did notice the spark plug was a little black but that did not concern me. I didn't see any oil inside the tube. I will check it again this weekend. Something odd did happen, after I pulled the plug for observation a drop of gas got on me from somewhere. I don't know where the drop of gas came from, but I could not find a leak. could the drop of gas have come from the spark plug? Thank you for your assistance.
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Old 08-07-2019, 05:12 AM
BabyUnicornTaco BabyUnicornTaco is online now
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Quote:
Originally Posted by DexMan View Post
good idea. When I checked the cylinder the second time (after noticing the code did not go away), I did notice the spark plug was a little black but that did not concern me. I didn't see any oil inside the tube. I will check it again this weekend. Something odd did happen, after I pulled the plug for observation a drop of gas got on me from somewhere. I don't know where the drop of gas came from, but I could not find a leak. could the drop of gas have come from the spark plug? Thank you for your assistance.


If you have a misfire the fuel didnít all burn up.


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Old 08-07-2019, 06:40 PM
HerbP HerbP is offline
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IF you installed all 8 new coils & spark plugs, I would start looking at the fuel injector on the #7 cylinder. If you got gas on you near the coil, one of the o-rings on the fuel injector might be damaged. Has anyone removed the valve covers lately, & had to raise the fuel rail?
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Old 08-07-2019, 07:43 PM
DexMan DexMan is offline
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No, the valve covers have not been touched. Is fuel injector replacement a hard DIY? Thanks again.
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Old 08-08-2019, 01:01 PM
HerbP HerbP is offline
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No, the valve covers have not been touched. Is fuel injector replacement a hard DIY? Thanks again.
There are 2 o-rings on each fuel injector. I had one fall off when doing my valve covers on my 645, not knowing it fell off. It did not leak fuel, but it did suck air causing a misfire. You simply need to raise the fuel rail up, then you can pull the injectors & inspect them. While I had them out I would clean them with some type of cleaner like brake cleaner,, or WD-40 which I feel safer with.
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