O2 Sensor problem after FI LTH install
 

Yesterday I had Fast Intentions Long Tube Headers installed on my 2011 370Z. Everything went smoothly except for a CEL. The codes I am getting are p0051 (low voltage on the o2 heater) and p1168 (closed loop control function) on bank 2 sensor 1. The car is running really rough and I don't want to drive it until this issue is resolved. I don't see how the sensor could be bad, it unscrewed from the factory exhaust manifold very easily and the mechanic was very careful with it. It was never dropped or bumped into anything.

The mechanic warned me that extending the wires on the o2 sensor was a bad idea. Suggesting that I should extend the wires on the cars wiring harness instead. He said that the solder can screw up the resistance on the wires and cause all sorts of issues with AF readings. I told him to do exactly what the directions said and now I have this issue. My car only has 6,000 miles on it and everything was fine before the install. After some research I discovered that the 2011 370Z uses a different pre cat o2 sensor from the 09-10. I was thinking that could be the issue but the bank 1 sensor appears to be working fine. I have searched and was unable to find any members with the headers installed on a 2011.

After the light came on we pulled the sensor out and checked all the wiring and connectors. Everything looked fine. If anyone has any advice I would really appreciate it. I was going to call Tony in the morning, but I would really like to fix this tonight. It's cold, raining, and my only other way to work in the morning is my motorcycle.

I got your pm and replied to that for you.

We send out 8 high grade, high temp. color coded wires with the headers.

-4 Black
-2 Blue
-2 White

They are already cut specifically to length and the instructions state specifically to only lengthen (1) original wire at a time. This way there can be no mix ups or wire crossing. Now I am pretty sure that you bought the headers used so i do not know if you have everything you need with them.

I have over 90 sets installed between the 370Z and G37 coupe and this is the first time I have encountered this. From the 2 codes your car has thrown, I am almost certain the mechanic that lengthened them did something wrong. Even though the (sensor probe itself) on the 2011 is different, that will not effect the outcome. As long as the correct wires are soldered back together and the correct wire is used, you should not have any problems.

I will be in the shop @ 8 am PST. Give me a call whenever you like and I will help you the best that I can. I am sure it is something that can be corrected somewhat easily...

Thanks, Tony

No offense whatsover but I would be looking for a new mechanic to work on your ride. From the sounds of it I would look over my header bolts too.. Good luck and hope you get it running right.

I'd start with resetting the ECU but after that I would check the lengthened wires to make sure they are securely soldered and wrapped. Sounds like a simple signal issue. FYI you are always going to throw codes with LTHs. Get a tune to disable them if you don't want it (that is what I did).

This advice is not (entirely) correct. Good advice in the first part of what you wrote as far as inspecting the wires.

On the second part you are not correct. You should not throw any codes with our headers. When installed properly, there should be NO CEL light or codes.

Thanks, Tony

Scott,

Thanks for the call this morning. I am sure once the wires are taken apart and then soldered back together you should be fine. Since it is an issue only on one side, I am quite certain it is just an installation issue.

Call me back if you need anymore advice.

Lastly, I look forward to getting your exhaust out to you so you can enjoy it with our headers...

Thanks,

After another phone conversion with Tony I believe we have solved the problem. The mechanic used an impact to remove the demon bolts and the vibration destroyed 2 of my o2 sensors. :facepalm:

Thank you so much for all the help today. I can't wait for the catback to get here.

I will overnight those new wires out tomorrow. You live and you learn man. I had to learn the hard way a while back for the same thing. I ended up buying that customer a new sensor. As we all know, they are not cheap for this car!

Tony

So I assume the solution to this is to pull the O2 sensors before you start disassembly?

You do not need to pull the manifold sensors before you remove the stock cats. You just cannot use impact tools on the cat bolts. I never do for this reason.

When I install the headers I pull the sensors after I remove the cats. I find the front sensors easier to get to with the cats out of the way.

Thanks, Tony

This my friends in excellent customer service.

OP
GL solving your problem. Sorry you have to get new 02 sensors.

After 10k miles on my headers I just through the same codes listed below. Tony how should I go about fixing this issue?

That is not a good thing. Scott982 explained to me on the telephone that power tools were used during the removal of the stock cats. We determined the power tools destroyed the front O2 sensors from the vibration they created.

He purchased 2 new front O2 sensors and has not had any issues since!

Please do not hesitate to call me if you have any questions...

Thanks, Tony

How do you test for a bad sensor? Will there always be a cel light?

Most times more than not there will be a CEL light if you have a bad sensor.

To FI INC.

I'd like to say I like how you are showing passion and care towards your customers. Repped

We appreciate the positive words! In my book this is the only way it should be!

Thanks, Tony

I am taking the Z to my GT-R Master Tech (He is the tech who installed my headers and CBE) this evening and hopefully we can come to the bottom of this. I cleared the codes earlier this week with my PC as a test to see if they would come up again and they did infact after about 200 miles. I will update you with what we conclude today.

Thank you very much for the reponse Tony.

I have been debating which headers to go with. After reading this thread...Fast Intentions all the way. Customer service has sold me.

Tony,

Do you offer HFCs installation at your facility? I would feel much better having somebody at your facility installed them

Please keep me posted. Once you have a conclusion it will be better for you to call me directly. You will be able to get a hold of me right away...

Thanks, Tony

Pleased to hear it. If you have any questions at all or when you are ready to place an order, please do not hesitate to call me directly...

Thank you, Tony

Call me!

Good morning Tony,

After leaving my sweet Alorah(Z) at the dealership for the past 3 days I finally was able to pick her up yesterday evening. The day I dropped it off I had both codes thrown and as I said in my previous statement I erased these codes only to have them come back again. The Technician working on my car only used torque wrenchs on the installation he claimed as this was the first question I asked him. I told him what I had read on this forum and how there was only one other incident of this happening out of (I said over 100 units sold) since I do not know the exact number. The Service Rep begin to blame the codes on the headers and then continued to tell me I didn't do enough research before I bought this unit. I quickly proceeded to tell him I did months of research and kept my self very informed via the 370z community and even yourself Tony. I also noted that after 12k miles this is my first issue directly or indirectly related to the headers that I have encountered. I told the tech to re-check the wiring and individually test the O2 sensors and everything was working properly after those tests. The Tech told me he could not pinpoint the issue since he could not get the codes to appear again once he cleared them. After picking up the car yesterday I have already put 100+ miles on the vehicle and I have not seen the codes as of yet. However their entire story and reasoning/answers behind everything greatly displeased me. I felt like I was getting the run around. Long story short the dealer/tech could not resolve the issue and cleared the codes. Any suggestions Tony? (I have noticed the car is running smoothly once again after the codes were cleared as it was running a bit rough previously)

Bump for answers!

T.

Glad we were able to talk on the phone and troubleshoot the potential cause! My ideas would of just been too much to write here!

Keep me posted as to what you find out...

Thanks, Tony

I appreciate the time you took to reach out to me over the phone and give me some much needed direction! I will keep you informed on the outcome of the tests. And that's for sure, you'd have written a novel! Haha!

Thanks, Troy

Really interested to see if this was resolved.

Peppers,

First of all congrats on the headers and welcome to the FI family.:tup:

I too had issues but not because of the headers but only because of installer ignornace.

I kept throwing a misfire code and a cataletic code which in return meant the 02 sensors.

Many cleared codes later and lots of trouble shooting. Come to find out. The damn shop put the 02 sensors in the wrong place. The primary was put inside of the J bend and the post cat was put inside of the header where the primary should of went.:shakes head:

BTW check your MAFs also on the intakes. Mine were dirty.

Hope this helps and FYI Tony has the best customer service hands down:happydance:

To me, this was a pretty cut and dry mis-wiring of the O2 sensors.

I goofed up mine the first time (to my dismay, since they aren't cheap).

I would bet that this was resolved by correcting the wiring and replacing the sensors.

After our conversation, this was solved an I never heard of another issue from Peppers. Our last conversation was almost a year ago.

Thanks, Tony

Wow, +1 for great customer service! I just joined the FI family last night when my exhaust came in (bought it used from skorch)

Congrats! We are glad that you have our exhaust one way or another. If you have any questions regarding the exhaust please do not hesitate to ask.

Thank you, Tony

Hello Everyone,

I have recently bought a long-tube headers (used) for my 370z which was perfectly installed but I came a cross the O2 sensors issue. The original wires are very short and I need to extend the wires.

Does anyone knows where can I buy longer wires? or extension cable/wire?

I need to buy them online for international shipment.

Kind regards.

You need to contact us directly to order them. They are pre cut to length. We can supply you with just them or the entire header installation kit. The best way to contact us to place the order is directly thorough my email below.

Thank you, Tony

Sorry to resurrect an old thread but I have similar problems.

Just installed the LTH's two weekends ago. Initially there was no CEL and I drove the car about 40 miles without issue. Then the CEL came on and stayed on and would not stay cleared. Eventually, 40 more miles later, the car started idling rough and would die after a couple seconds on start up. I had it get it towed to the shop. Our initial feeling is that the O2 sensors were wired wrong and that I had crossed the two black wires on one/both of the O2 sensors. Not knowing which sensor was the mistake, two new O2 sensors were purchased and very carefully the wires were spliced one by one (new wire was used for the splice. We did not reuse the wire provided by FI).

However, the car is still throwing codes P0053, P0300, and P2096 on the passenger side O2 sensor. Also, the passenger air/fuel sensor is reading 5v when it should be low to mid 2v. Could it be possible that crossing the black wires on the O2 sensor would have caused a short in the ECU such that the 5v source signal is not even reaching the O2 sensor anymore but is shorted in the ECU?

So, any suggestions? We have been told to reinstall the FI supplied splice wires back into the O2 sensors and will give it a try tomorrow. We rewired the new O2 sensors with new wire so we think it is strange that this cause the problem since only the passenger side is throwing codes and not the driver side as well.

Just to come full circle with my problems in case anyone else screws up like me:

The black wires were crossed on the passenger O2 sensor that needed extended. This caused one of the pins in the PCM to burn out. Essentially, one black wire has 12V on it and the other has 5V. When the wires were switched, the 12V signal was to the 5V pin which caused the problem and burned out the pin in the PMC. This also explains why the other A/F sensors was reading a steady 5V on the scan tool.

The car ran for about 100 miles as the computer "adjusted" itself and eventually adjusted itself into car suicide. The only way to get it to run with the bad pin was to unplug the O2 sensors and run the car in a closed loop. I bought two new O2 sensors, a new PMC, and needed a flash from the dealer on the new PMC. The repairs cost more than the actual headers because 5 cents worth of wires were crossed. Moral of the story: take your time and read the damn instructions!

But oh my does the car sound excellent! Great quality product by FI!