Jeffwilson34

Car has long tube headers and has the rear sensors unplugged.
I had some problems least month with faulty wiring.
I finally got it all fixed and running good. I started getting a P0151 code.
but it still ran good. It was a nice day today so I took a look.

Side note, the shop that installed the headers did a hack job on the harness to the sensors, when I complained the owner looked at it and fired the guy on the spot, they offered to fox it but it would be a few weeks before they could do it or he would give me a partial refund.
It was running good and the splices did look good so I took the money.

Back to today, I found I had not secured the O2 wires correctly and they were melted on the pipes. I removed the bad section and spliced new wires into it. It took a while to find the correct wires for the heater and signals. I thought I had it correct but it ran rough and misfired.
The heater wires to the sensor were both brown and I had been told that it did not matter which was used as hot or ground, Is this true?

I swapped the signal wires and it ran better but still gave me the 0151 after a while.

Could the sensor be damaged by having the wires reversed on the heater?

The wires look like 2 brown a violet and a lighter color maybe yellow.


The car runs best with the right sensor unplugged.

I have a OB2 Diagnostic program called scanpro XL and USB connector for my laptop
When I bought it I did not know they had no real guide as to how to set things up only a Q&A forum
I can look at the O2 Data but have no idea what it means.

Any tips on what type O2 sensor to get?

am I correct in the Violet is sensor high and the lighter color sensor low? and browns heater wires?
Probing the wires coming from the car harness with the ignition on gives me 12v on one brown the other is ground, the violet shows 3v the light 1v
When the car is running with the sensor unplugged I get some voltage from the violet

At the moment it is running fine with the sensor unplugged but the right bank is running rich and my gas mileage sucks.

Mickeyrx70

similar problem.....also interested in replies.

Dcollins3208

I got Bosch 15703 o2 sensors. Not good to cut into the wiring if you can avoid it, just buy the 15703s and get front o2 sensor extensions (if you don't have them already). I got the 15703s on ebay for about $26 each, I think Autozone has them for around $45. Most forum sponsors will have the o2 extensions

n8dogg

I'd recommend locating the shop manual and 02 sensor schematics. If the car ran fine before the shop messed up the harness, and ran like crap after, I imagine it is due to the wiring, not the 02 sensor(s).

Do you have the rear 02's crossed? If they are not, it will run like crap.

Simple solution, remove the rear 02 sensors all together. Cap the bungs. You'll get a check engine light, but the car should run fine. If it does not, then you have other issues. Make sure the 02 sensor harness wires are not exposed and shorted to each-other or ground. As long as it runs fine, have a tune performed and make sure they eliminate the rear 02 sensor codes etc...

Dcollins3208

I think he's referring to the front o2 sensors because his rears are unplugged, and p0151 is a bank 2 sensor 1(passenger's side front) o2 sensor code. But yes, do have the rear o2s tuned out, all they do is monitor the catalytic converters. As n8dogg said also, check for shorts, exposed wiring, etc. I still recommend trashing the o2s you have now since they have been cut into and purchase new ones with extensions. Front o2s are an integral part of how your car performs

warlock007

what are the switch point numbers when scanned?

if they are between 300-600 mostly, it is a indication that it is either bad or going bad.

Hows the spice work done, soldered or twisted?

I never had to use any extensions for my headers (Kooks) but I would think that extensions made for it would always be better than cutting.

Have you tried swapping the O2 sensors and seeing if the code follows?

Bill Curlee

Here is the schematic that you need for repair and troubleshooting. IMHO, the polarity of the heater wires does not matter but,, for consistency sake, i would follow the schematic.

You need to make SURE that you have proper heater voltage. Use a DC Volt meter and read the voltage on top of the fuse at the test points. You should see FULL BATTERY voltage when the ignition is ON.

After approx. 2-3min of ON time, CAREFULLY feel the base of the O2 Sensor. It should be HOT to the touch.

Find a way to DATA LOG the PCM.. Some higher quality Code Readers have Live Sensor Data and are able to show you the O2 Sensor output.

If the sensor is working correctly, it should fluctuate HIGH TO LOW,, LOW TO HIGH....., 100 millivolts to 900 millivolts. If it just hangs out at one voltage or doesn’t fluctuate to its full range, the sensor is most likely bad or weak. If you rev the engine, the sensor should peg HIGH and on engine coast down, it should swing LOW..

I use an ACTRON CP-9180 and it has LIVE SENSOR DATA and O2 sensor output info

Jeffwilson34

Part of my problem is I like to fix things myself when I can. If I do not know how to I research it and make notes before starting. My thinking is, I would rather learn how to do something hands on even if I mess up a time or 2 other than relying on someone else to do it for me. When I run into something I can not do or would be expensive if I screwed up I take it to someone who knows what they are doing.

The header install was a couple years ago. The rear O2s were tuned out years ago also and are capped off although before the tune I had simulators on them. On the car Harness they have a square plug and the front have a flat plug that has been spliced into the harness so I do not know what it had to begin with.
The problem started when (I) screwed up and let the wires hit the headers last month when fixing other problems.

If any wires crossed it was me not the shop.
I know by probing which 2 are the heater circuit on the car harness but an not positive about the actual O2,
I am not sure which of the other 2 are for signal high and low The wires I see that run back to the O2 looks to have 2 brown 1 violet/purple and one pink but till I can get under it and check I am not sure if they are just another splice. ! seems to be a dedicated ground and another seems to have some voltage coming from it when it is how even though it is not plugged up I am assuming that it somehow creates voltage from the heat and exhaust gas passing through the actual sensor part of it
The harness looks to have 1 black 1 brown 1 purple and one yellow or white

I tinkered with it more and got rid of the P0151 and the gas mileage is better but now I am getting a P0160 which is a bank 2 sensor 2 code which was turned off in the tune and has never been on before

I am not sure why but the original harness plug was replaced when the headers were installed I suspect he damaged it somehow and replaced it with one with a red white brown and black.
He spliced it into the harness pretty far back so I can only see about 1/4 inch of the original wire to be sure of the colors.

I do not have a garage or access to one at the moment. I have to jack the car up in a gravel driveway and crawl under it to get to the sensor.

I am going to buy a new plug and for the harness. I found one on an auction place that comes with the plug and pins, so you can crimp the OEM harness wires into the pins and put them in the correct spot.

I plan on buying a new sensor and harness extender.
I am not sure when I will be able to install it because of the weather.

At the moment it is running fine and the P0160 code does not seem to effect the running and mileage like the the P0151 did.

I have the wires together with twist wire nuts because I did not want to do any more long time splicing by soldering and shrink wrap till it was fixed. Now I am scarred to mess with anything.

I do have a set of simulators somewhere I used for the rear before they were turned off in the tune. I am going to look for them and see if installing them will remove the P0160.

I hate having any codes even though I have done everything I can think of to fix the torque management codes that will not go away.
They also light up the traction control light on the dash but do not seem to have any effect on the actual working of traction control.

I can not complain much though it has served me well for over 5 years and has over 300,000 miles that I put over 200,000 on myself.

The biggest problem I have had was the radiator letting coolant and transmission fluid mix which ended up with a rebuilt transmission and a dedicated transmission cooler bypassing the radiator.

Jeffwilson34

@ warlock007 I will have to hook the laptop up again and see if someone on the scanpro forum will tell me how to test the O2's there is a tab dedicated to O2 sensor diagnostics I just do not understand how to read it and there is no user manual for the program which is odd I thought considering the price of it.

@ Bill Curlee
I have 12V going to what I think is the heater wires but untill I can get under the car to remove the sensor I can not test and see if it is getting warm.

The only diagnostic tool I have is scanpro with a USB unit that plugs into the port under the dash and into my old laptop with the program on it. I am trying to find someone on their support forum to help me with reading the data.

Thanks to all for the help,

Jeffwilson34

I finally got the problem fixed. I hooked the wires where my best guess from the info I had. Then I soldered them at the splice, covered them with clear silicone sealant, heat shrink each wire then finally heat shrink the harness and routed it away from heat and secured it with zip ties all nice and neat.
I the harness which included the capped off rear plug near the plug wire while having problems. I am wondering if the EM field from the plug wire when it fired was messing with the sensor readings at the PCM. The plug wires are new but hold a EM meter near any plug wire while the engine is running and it goes crazy.

I took it to my private little test track and did a couple 1/4 mile runs the 1st was 11.7 ET 113MPH which is a bit slower than before I started having problems. I could get 11.2 to 11.3 and 120MPH +/- a few pretty constant That is using the Drag timer on the scanpro program It is pretty accurate when compared to what it shows when I go to Bristol drag-strip on their street-fight nights
On my 2nd run I snapped the belt which is just my dang luck. I had an old belt I had in the rear compartment I saved when I put a new one on. But the belt somehow grabbed the wires from the mass air flow and ripped them out of the plug.
I thought last friday was friday the 13th.

Jeffwilson34

I am attaching a pic of what the program looked like when I did a screen cap, can you tell anything from it. It is bank 2 bank 1 is almost the same.