Found my electrical issue, need advice
Thread Starter
Burning Brakes
Joined: May 2007
Posts: 911
Likes: 27
From: Southern IL
Found my electrical issue, need advice
I got a "Charging Fault" about around the same time I noticed my passenger O2 wiring harness had been partially melted by the header due to a sloppy install. The rear sensor got the worst of it, but they are deleted in the PCM anyway.
I repositioned the O2 harness and didnt assume anything was wrong...because there were no codes thrown.
I noticed after the engine runs for 30 seconds, there is light smoke coming from my passenger header area, could never pin point exact where it was coming from. I just thought it was PAG oil that had leaked and had not yet burned off.
I decided to ohm out the rear O2 sensor connector just to make sure, and found 2 wires shorted both to each other and ground. I checked the drivers side as well, and it comfirmed the short.
Now my problem is...I have already removed the connector (which is the part that got melted) and the wires seem to be fine going into the main wire bundle, but the short still exists with the offending connector gone. I am wondering what my best option is from here.
Since this PCM has the rears deleted, would it save alot of trouble to just clip the rear O2s at the fusebox?
I repositioned the O2 harness and didnt assume anything was wrong...because there were no codes thrown.
I noticed after the engine runs for 30 seconds, there is light smoke coming from my passenger header area, could never pin point exact where it was coming from. I just thought it was PAG oil that had leaked and had not yet burned off.
I decided to ohm out the rear O2 sensor connector just to make sure, and found 2 wires shorted both to each other and ground. I checked the drivers side as well, and it comfirmed the short.
Now my problem is...I have already removed the connector (which is the part that got melted) and the wires seem to be fine going into the main wire bundle, but the short still exists with the offending connector gone. I am wondering what my best option is from here.
Since this PCM has the rears deleted, would it save alot of trouble to just clip the rear O2s at the fusebox?
Last edited by Vicarious.; Nov 13, 2011 at 09:35 PM.
Tech Contributor
Joined: Jan 2007
Posts: 19,393
Likes: 1,135
From: Dyer, IN
So evaluating two wires with a meter, you found them shorted? Which wires exactly? When you tested the resistance, did you pull fuse 15, and have PCM connector C1 disconnected?
Thread Starter
Burning Brakes
Joined: May 2007
Posts: 911
Likes: 27
From: Southern IL
I measured 2.2 ohms between what looks like the black & brown wires. It is damn near impossible to distinguish them by color in their old age. As you can see by the picture, i just crushed the melted plastic around the connector.
Tech Contributor
Joined: Jan 2007
Posts: 19,393
Likes: 1,135
From: Dyer, IN
Had fuse 15 pulled, not the pcm connector, which color is C1?
I measured 2.2 ohms between what looks like the black & brown wires. It is damn near impossible to distinguish them by color in their old age. As you can see by the picture, i just crushed the melted plastic around the connector.
I measured 2.2 ohms between what looks like the black & brown wires. It is damn near impossible to distinguish them by color in their old age. As you can see by the picture, i just crushed the melted plastic around the connector.
...and to answer your original questions........no, I do not thing cutting the wire at the fusebox is an acceptable fix .....just my opinion.
Last edited by lucky131969; Nov 13, 2011 at 10:54 PM.
Thread Starter
Burning Brakes
Joined: May 2007
Posts: 911
Likes: 27
From: Southern IL
Haha, I should have known the answer to that question already. Just had to ask to be sure.
I don't see any other heat damage further up, so digging through the harness could be interesting.
lucky131969, as always, thanks.
I don't see any other heat damage further up, so digging through the harness could be interesting.
lucky131969, as always, thanks.
I believe C1 is blue, but it takes another few seconds to just disconnect both. It's the only way to truly isolate all the O2 wiring, and know exactly what you've got. Personally, I would find the melted wiring. It can't be that hard to find, because it has to be in close proximity of the exhaust. If you can be certain of the wire colors, it will help. From the pic, it appears that you have a tan/white stripe, purple/white stripe. That would leave black and brown, with brown being the 12 volt feed for the heater circuit.
...and to answer your original questions........no, I do not thing cutting the wire at the fusebox is an acceptable fix .....just my opinion.
...and to answer your original questions........no, I do not thing cutting the wire at the fusebox is an acceptable fix .....just my opinion.
Tech Contributor
Joined: Jan 2007
Posts: 19,393
Likes: 1,135
From: Dyer, IN
Just checking, but you do have the other three O2 sensors unplugged, right?
Last edited by lucky131969; Nov 14, 2011 at 12:42 AM.
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Tech Contributor
Joined: Jan 2007
Posts: 19,393
Likes: 1,135
From: Dyer, IN
Yep, you need to have ALL the O2s disconnected(and fuse 15 removed)......or.....you will read through the other heater circuits, since all the brown wires are connected together at the load side of fuse 15.
With all O2s disconnected you should read very low ohms on the black wire(ref to ground), and open (or infinite ohms) on the brown wire, as well as open (or infinite ohms) between the black and brown wires.
With all O2s disconnected you should read very low ohms on the black wire(ref to ground), and open (or infinite ohms) on the brown wire, as well as open (or infinite ohms) between the black and brown wires.
Thread Starter
Burning Brakes
Joined: May 2007
Posts: 911
Likes: 27
From: Southern IL
bummer man...after I unplugged the fronts, the short has disappeared. This smoke coming from my passenger header area has got me worried really bad now.
There is no visable oil on the header, and it doesnt really even get hot enough by the time the smoke shows up.
The smoke is so light (and it doesn't look or smell like exhaust), it's impossible for me to narrow it down, and I cut the engine off at the first sight of smoke. I can't help but think that it's got to be an electrical fire or something, especially since I've got the newly accuired charging fault.
My A/C relay & fuse have both been pulled already so thats out of the question. This thing is mind boggling...back to the drawing board.
By the way, is there a precise tool that measures low DC amperage without breaking the circuit? I've got a good amp clamp, but it was designed for high current.
The only 2 active codes I pulled are for Outside Air sensor, and the other is for the A/C circuit unplugged. O2 sensors deleted.
There is no visable oil on the header, and it doesnt really even get hot enough by the time the smoke shows up.
The smoke is so light (and it doesn't look or smell like exhaust), it's impossible for me to narrow it down, and I cut the engine off at the first sight of smoke. I can't help but think that it's got to be an electrical fire or something, especially since I've got the newly accuired charging fault.
My A/C relay & fuse have both been pulled already so thats out of the question. This thing is mind boggling...back to the drawing board.
By the way, is there a precise tool that measures low DC amperage without breaking the circuit? I've got a good amp clamp, but it was designed for high current.
The only 2 active codes I pulled are for Outside Air sensor, and the other is for the A/C circuit unplugged. O2 sensors deleted.
Last edited by Vicarious.; Nov 14, 2011 at 03:11 AM.
Thread Starter
Burning Brakes
Joined: May 2007
Posts: 911
Likes: 27
From: Southern IL
Two questions that can help me narrow this down..
1. How safe is it to idle the engine with the front O2s disconnected? On top of that, my PCM & injectors were both altered significantly, and it has not had any chance to relearn the idle. I can't accomplish that I until I can prove I am not looking at a potential electrical fire.
2. Is there any reliable way to prove beyond a doubt that the smoke is coming from a small header leak rather than an electrical short?
1. How safe is it to idle the engine with the front O2s disconnected? On top of that, my PCM & injectors were both altered significantly, and it has not had any chance to relearn the idle. I can't accomplish that I until I can prove I am not looking at a potential electrical fire.
2. Is there any reliable way to prove beyond a doubt that the smoke is coming from a small header leak rather than an electrical short?
Tech Contributor
Joined: Jan 2007
Posts: 19,393
Likes: 1,135
From: Dyer, IN
It will run like crap. You will need to get under the car while it's running, to determine the origin of the smoke. If you really have concerns about a flame up, have a small fire extinguisher at the ready.