Dodge Nitro Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
I have a 2008 nitro with the 3.7L. Cylinder #5 has a misfire and I figured out that the blue with yellow stripe wire in the connector for the coil has an issue. I've tested the resistance on both wires in the #1 and #3 cylinder connectors and they are all about 15.30. The brown wire in the #5 cylinder connector is also 15.30 but the blue with yellow stripe is 4.60. I tested the voltage of every coil connector wire and they all check out at about 14.37v while running but that one wire on #5 just makes my ohm meter go crazy. I looked at all the wires in the connectors under the fuse box and I looked at the wires going to the computer on the passenger fender but I can not find where that wire goes. Maybe someone can link me to a diagram as to where that wire leads to so I can investigate further. Maybe someone has seen this before and has a cure? Any help would be greatly appreciated.
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,459 Posts
Welcome to the forum TheLostNitro. When you have a chance, head over to the Newbie Section and say "Hi".
Tell us a little about yourself and your ride.
That way we can welcome you all proper like.

DB/YL goes to the PCM and is the coil control.
My guess is the coil is bad.
Have you tried swapping the # 5 coil pack with another cylinder?
If you do and the misfire follows, then the coil pack is bad.
 
  • Like
Reactions: Nitrogen

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,459 Posts
If you want to test the coil control, disconnect the plugin at the #5 coil.
Connect a test light to 12V and probe the DB/YL hole in the plug.
Make sure nothing is going to get caught in the fan!
Turn the engine over for 5 seconds or so, while watching the test light.
The light should blink brightly. If it does, the coil control is working.
 
  • Like
Reactions: Nitrogen

·
Registered
Joined
·
5 Posts
Discussion Starter #4
At first I thought the coil was bad because I put a new set of sparkplugs in and the miss was still there. I got a new coil but that did not help so I swapped it with another cylinder and still nothing. I swapped the sparkplugs also. I have tested it with a test light but nothing happens. While I was checking the resistance of all 6 wires on the driver side cylinders I checked with the coil connected and disconnected with the same results. Where is the pcm located? Does the blue/yellow wire go from the #5 cylinder coil plug straight to the pcm? Or does it splice into/change color somewhere on it's path to the pcm?
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,459 Posts
Did you run the coil control test above?
Disconnect the Neg(-) battery cable before you remove the PCM plugs!
Reconnect Neg(-) as needed for testing, then disconnect Neg(-) before reconnecting the PCM plugs.
PCM is inside RF fender.
Key off;
Do not probe the PCM harness connector holes! They bend easily and will no longer make contact.
Check Pin1 at the coil plug to ~ PCM connector 2(BL/OR), Pin 2 for continuity, short to ground or voltage. The wire is DB/YL all the way. I do not see any splices in the diagrams I have.

With the 3.7, only ZFR6F-11G plugs should be used, changed every 30K miles. OEM is NGK brand, and is what I use.
 
  • Like
Reactions: Nitrogen

·
Registered
Joined
·
5 Posts
Discussion Starter #6
I went with ngk plugs also. I found the wire in the orange plug you mentioned. It is the second one from the top right. I ohmed it out and it showed 00.0. I just went ahead and stripped some insulation back on the wire at the pcm plug and the same at the coil plug and ran a new wire but I left the old wire in tact. I did not cut it.. yet. It still misses on that cylinder. Nothing changed. I checked the voltage at the coil connector and it shows the same voltage as the other ones now. I pulled the plug out and it is wet. I have a new code p2314. I could have set that code myself because I unplugged the connector to the coil while it was running to see if it died down anymore but no change. I unplugged it when I first started diagnosing the misfire and it never set a code but now it is. I swapped the plug again and the coil again to see what happens but no change. My question now is, do I cut the factory wire? Would it even change anything by cutting the wire since I alread ran a new wire between them? I'm guessing that won't make it start firing. Maybe a new pcm?
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,459 Posts
You may have to clear the codes and try again. The PCM will kill power to the injector when a misfire is detected.
P2314 = Ignition coil E, secondary circuit - malfunction,. Possible causes; Wiring, ignition coil.
Yep, unplugging the coil wire could cause this.

Did the wire show a short to ground or B+?
Did you have the PCM C2 and the coil #5 plugs disconnected when you did the Ohm test?
Did you do the coil control test above?
PCM pins and plug look OK?
 

·
Registered
Joined
·
5 Posts
Discussion Starter #8
Yes I had both plugs disconnected before I did the ohm test.

Coil control test failed.
I cut the blue/yellow wire at both the pcm and coil connectors and left the new wire I ran between them and the coil control test passed.

The blue/yellow wire I cut had a short to ground. I tested it after I cut both sides.

All pcm pins look good in all 4 pcm plugs and the coil connector pins look good.

I cleared the codes and the cel went off and hasn't came back on. Yet, my spark plug is still wet and it still misses on that cylinder. I also swapped the plug and coil again.
You would think that if it was missing I would get a misfire code but I never got one since it started missing.

Is there anything else I can try?
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,459 Posts
Coil control passed with new wire. Yea! That is a good thing. At least that part is not a PCM issue. All else looks good as well(except the short to ground). Thanks for the info.

The questions now are;
Why was the old wire shorted to ground and where?
What else may have also melted/shorted?

If the PCM and TIPM were not getting accurate, or getting conflicting inputs, you may not get a misfire code, but would get a CEL saying something is wrong.
What codes did you clear?

Try a Neg battery disconnect for 10 minutes to reset the computers.

If I remember correctly you said you have 12V+ on the other #5 coil wire with the ignition in Run position, so...
It is possible the short may have fried the coil...

Test the spark plug/coil;
CAUTION, do this at your own risk! The remaining fuel and fuel vapor can catch fire!
Pull the fuel pump fuse, start the rig and run it till it dies. Try to start it more until it will not fire..
Pull the coil and plug, (put spare spark plug into head to seal off vapor.) Spark plug still in the coil and coil wires still plugged in, ground the spark plug and visually look for spark when cranking.
Stuck injector. Injector control. Rocker arm fell off/valves not opening.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #10
I done the coil/sparkplug test while it was running because I did not have a helper to turn the key for me.

The test passed.
The original coil was still good.

I read a post on this site about someone having a misfire but it turned out to be the rocker arms have fallen off. So I decided to check my rocker arms since I now know I have spark and since you also mentioned them.
As it turns out, both the intake and exhaust rockers fell off. One of them got stuck under the intake lobe and put deep scratches in the high spot of the lobe and the rocker arm roller was beat up and scratched pretty bad.
I sanded them a little bit with 600 grit but they still looked pretty bad so I just decided to put it back together anyway. I used my rocker arm tool to install them but I did not actually need to use the tool on the intake side because the valve was bent and would not fully close. I tried hitting it to see if it would pop up but after looking at it better I noticed it was bent really bad.

That kind of left me at a stand still. I'm more than capable of fixing it but it's not really worth it to me. I know this guy who has a boat that I might just trade it for.

I also found out the hard way where you should never touch one of these coils while testing for spark.

I really do appreciate you sticking with me to get this issue resolved. You have had very knowledgeable answers for every question I had. I suppose that's why you are a moderator. I couldn't have done it without your help. If I had a brick of gold I would give it to you.
 

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,459 Posts
Glad to assist. That is what this forum is all about. Nitro owners helping other Nitro owners.
Bummer you have a bent valve. These engines are 0 clearance, so it is possible the piston has a hole popped in the top as well. Won't know for sure till the head is off, as you know. If you decide to go that route...

My Mod status was/is based on recommendations from other staff members and the Admin team of the forum.

Sorry in the end is was not great news, but it's not a total loss either.
At the very least, other Nitro owners with similar symptoms will have something to reference and a few tests they can run.

No gold required, your complement and thanks is enough for me. :)

Oh, and yes, it can be a "Shocking" experience when testing a coil.
Been there, done that. :rolleyes:
Our Nitro likes to tow a boat!
 
  • Like
Reactions: Nitrogen

·
Khaki Nitro Nut
07Lifted,4X4,6sp-man,3.7L
Joined
·
30,459 Posts
Welcome to the forum Brunko. When you have a chance, head over to the Newbie Section and say "Hi".
Tell us a little about yourself and your ride.
That way we can welcome you all proper like.

Please do keep us posted.
 
1 - 13 of 13 Posts
Top