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Old 07-25-2010, 09:05 PM   #1
flightwatch
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Default Need some help diagnosing an issue

After a nightmarish experience with a header install, and some really really bad advice from my tuner, my car is running like ass. After the header install, I realized that I didn't have an o2 extender. I called my tuner to ask his advice about what I could do. He told me that I didn't need to run any o2 sensors...I asked him 3 times, and he said just that 3 times. I didn't know any better at that time, but I do know now that I need the front o2 sensor. Well, my car has been running hella rich for the past couple of days...not to mention the ecu being in limp mode. I went to my mechanics house today where he made the o2 extender out of the rear o2 sensor wire, and we got the sensor in place. We reset the ecu and off I went. Now the ecu is supposedly reading off of the new found front o2 sensor, but my car is still majorly anemic. It just won't get up and go. It's also got some good pinging going on down low (-2500rpms) The only thing that I can think of is that the car is knocking and pulling all of the timing, but I'm not getting a cel at all...much less a knock code, and I'm quite positive that my tuner didn't disable that DTC.

I have a call into my tuner so that he can datalog/re-tune my car asap, but that won't happen until at least tomorrow.

What do you guys think? MAF sensor fouled due to my pig rich condition? I'm kinda a a loss. I'm almost to the point where I'm gonna throw my stock manifold back on, but if there is an underlying issue, then I want to get to the bottom of it.
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Old 07-25-2010, 11:33 PM   #2
Storm
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Reset the ECU first and foremost. You've confused the hell out of it by running the O2 sensors in free-air. It should've popped a code for both sensors actually....but either way, reset the ECU now that the sensors are in place. If it still runs like ass....ask your tuner what kind of wire he used to make the extender.....The sensors are operating in a range of 1v for narrowband and 5v for a wideband. A small voltage drop from the wrong wire type will lead the ECU to think the mixture is something other than what it is....and run poorly when trying to compensate.

You can't foul a MAF from running rich. It is metering airflow before any fuel is brought into the mix....think about how things are setup under the hood.
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Old 07-26-2010, 12:45 AM   #3
flightwatch
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Thanks for the tips...I did reset the ecu after reinstalling the front o2 sensor. My tuner actually turned off the DTC's for both o2 sensors hence why their is no cel. I will be having him turn on the front o2 DTC tomorrow morning. Since I'm only running the front o2 sensor, we used the rear o2 sensors wire to make the extender. The MAF sensor was a suggestion by a friend. It doesn't make sense to me, and it's highly unlikely that it would be fouled.

The car seems to be running much better now, but I am still going to have my tuner do some datalogging tomorrow. To me, it just seems to be having a hard time getting into open loop...even though the delays were tuned out.
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Old 07-26-2010, 04:44 AM   #4
flightwatch
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While driving home from work tonight, my cel comes on with the whole blinking cruise light. I am truly at a loss because I don't think it was knocking...she didn't pull any timing. The car was running good from what I could tell. I don't know what to think.
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Old 07-26-2010, 05:43 PM   #5
flightwatch
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I got the cel read, and it's the wonderful P2096 code. I'll have to chat with my tuner about it, but I don't see it as being a big issue.
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Old 07-26-2010, 06:37 PM   #6
jason95rip
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You need a new go-to guy for info! Anyone who thinks a car can properly run with no O2 sensors should not be allowed anywhere near the hood latch of a car.
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Old 07-27-2010, 03:05 PM   #7
flightwatch
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Question...Do I need to run the rear o2 sensor as well? It won't be hard to throw it in if I need to.
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Old 07-28-2010, 09:53 PM   #8
flightwatch
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Since I am talking to myself in this thread, I'll go ahead and ask myself if I know what type of wire I should get to make an extender for the rear o2...Well, I don't so I will try to ask this 1 more question before I give up on NASIOC.
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Old 07-28-2010, 10:16 PM   #9
motohippy
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I'll put in my .02, even tho I'm by no means an expert on engine management. AFAIK, the rear O2 sensor is there to check the efficency/effectiveness of the cat, and plays no role in engine management. However, its presence will make the ECU happier, unless it's been disabled somehow. If anyone knows better by all means correct me, learning is good.
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Old 07-28-2010, 10:40 PM   #10
flightwatch
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Thankyou Sir for your input...at least you are trying to help out. One nice thing about having an issue with your car is that you learn stuff from it.

On newer models, the rear o2 does more than make sure the cat is working. It also aids in the LTFT. I'm confusing my ecu because I am not running a rear o2. The ecu is getting the STFT from the front o2 and correcting the AFR on a second by second basis. Since I am not running a rear o2 right now, the ecu is reading atmospheric air instead of post-cat exhaust from the rear o2...hence the post catalyst fuel trim too lean (p2096) code. Since figuring this out, I am trying figure out what gauge wire I need to get so that I can extend the harness and get the rear o2 happy.
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Old 07-29-2010, 01:21 AM   #11
AWDWRXLOVER
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Quote:
Originally Posted by jason95rip View Post
You need a new go-to guy for info! Anyone who thinks a car can properly run with no O2 sensors should not be allowed anywhere near the hood latch of a car.

my car runs fine with out them...
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Old 06-20-2012, 02:46 AM   #12
Sleeper_RS
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^^^^^ yeah haha ok check ur AFR and tell me it runs fine lol
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Old 06-20-2012, 02:51 AM   #13
Sleeper_RS
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@ flight watch what year is ur car?
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