Can anyone confirm the O2 sensor used on Buick regals was narrow band? From what I can tell all the LNF?s ran wideband, but LHU may have used narrow (which is what I have).
Also, can anyone share a log of what O2 voltage should look like during cold start? I'm seeing 1.278v with the engine off regardless of if a sensor is connected or not. This makes me think the ECM is toast.
a 2011 buick regal will use a narrow band primary O2 sensor:
O2 sensors: 2011 regal turbo primary (upstream) O2: GM pn: 12616502, i expect this to be a narrow band sensor
O2 sensors: 2011 regal turbo downstream O2: GM pn: 12640115
I believe it was 2016 when they switched to the E80 controller that GM vehicles started using wide band sensors
the LNF is an outlier because it was a Bosch controller, bosch software, and bosch wideband O2 sensor.
I'll try to get a log for you on a stock turbo regal later today.
My guess is that you are still too lean, add another 30% to your MAF curve and try again. Or better off, you could buy a wideband O2 setup and we can stop guessing.
Thanks. I will definitely consider a wide band, but I shouldn't need one to get the damn thing to idle. I tested my original and replacement O2 sensors this weekend and both were bad. I've also noticed that the calibration has a 1.25v O2 readiness setting. This suggests the ECM uses 1.278v as a default until the O2 sensor is warm. Once warm the ECM will go into closed loop and start reading the O2 sensor. In my case that is zero because the sensors are dead.
I also figured out why fixing the wiring to the O2 sensor caused this change. With the connector on backwards the signal wire was connected to the heater, the other end of which was connected to sensor ground. This means the ECM was basically seeing a sensor wire connected to ground. I also confirmed that when I touch the signal wire (key on, engine off, and now O2 sensor connected) to ground the ECM does see this (O2 voltage drops to zero). I then tried connecting a few nearly dead 1.5v batteries across the signal circuit and the ECM did report a <1.5v reading. This convinces me that ECM is working. The only things I haven't confirmed are: 1) Does the ECM read the same voltage that I measure independently, and 2) why did the second O2 sensor fail? The first one I can test by measuring the voltage across the battery at the same time the ECM does, but I can't really prove the cause of the second. I'll just have to buy a new sensor and give it a go.
I'm also not sure why the heater circuit DTC was made. Maybe I didn't reset the DTC's properly when I changed the sensor, but when I read the resistance between the two bad sensors they are both reading 3.5ohms (approximately). This doesn't suggest a dead heater to me. Again, I'll just have to plug a new one in and see. Unfortunately I can't easily use the exact Regal part, but cause my harness is not setup for that.
All of that has absolutely nothing to do with the crazy cold start since that happens when it's in open loop. I agree this could be caused by a lean condition, but I'm not sure why. I guess I could just be on the limit of some table which is extrapolating some crazy numbers. Besides what I mentioned earlier about PCV being gone I also did finally connect the dots you laid out for me regarding intake manifold temperature. Currently my only source for air temperature is the MAF. I know this because when I disconnect the MAF I lose this signal. My manifold air temp is pegged at -10?C and my ambient air temp at 0?C. I don't think the ambient matters, but the manifold definitely could. In the mean time of trying to get that sensor hooked up I'm going to try modifying the calibration for it so the default is closer to ambient and see if that fixes anything.
If I can get the O2 reading and this additional sensor in place I have to believe it will change something. I've also added 15% more fuel as a happy middle ground between where I was and your suggestion. This should almost guarantee I can't determine what cal change results in whatever running change I see...this is what they tell you to do when troubleshooting...right...right?
In addition to all that I also changed my transmission to automatic which at least forced the vehicle speed to go to zero. I don't know what other issues that will generate, but at least it should remove any doubt I had about the ECM having odd targets because vehicle speed was pegged at 158mph. I had "no sensor" selected, but who knows.
I'm feeling more confident now, but the proof will be in the pudding. Thanks again for the continued support!
Not a real "cold" start. car had been sitting for 2 hours, about 2C ambient temp. stock 2013 regal.
Anyway, it gives you an idea of amount of airflow, throttle, map, spark, etc.
For some reason i couldn't add more signals... something didn't make sense... i expected to be able to add a LOT more signals, does anyone know why i couldn't see more signals to add???
meh, anyway.
Dude, thanks! You also have a 1.278v reading on the O2 sensor! This suggests my only issue with O2 is a dead sensor.
I talked to a friend that works at Denso that can get me the specification for the heater resistance on the Regal as well. If he confirms that it's a 3.5ohm sensor (or nearby) then I should be good. Based on the time it took for your sensor to turn on it seems that I should be good to go. Apparently my parts store sold me a dead sensor.
why don't you just disconnect the O2 sensors, the car must run then...in open loop but it must run...so at least you can figure out your MAF readings.
i lately also had an issue on my car when switching back from my big 100mm CAI to stock airbox, somehow some small debris fell into the MAF sensor, making it read faulti, car also was heavily oscillating then, double checked with a second MAF...was ok...blow out the first MAF...worked... what I want to say...maybe you MAF is also faulty.
The short answer to why I don't disconnect the O2 sensor is that it should work and the engine is only unstable while in open loop. So, they are really two separate issues. If I can get closed loop to work it should stabilize, but I'll still need to fix the open loop issue to avoid a crazy cold start.
What did the MAF signal look like when you were seeing instability? Did it look normal in the log?
I am using your layout . Thanks for that. I haven't started the car with it yet, but that will happen next.
TurboWood,
You could give this a try: turn off the MAF sensor and see what it does when it's forced in speed density.
To turn the MAF off, under Engine Diag >> Airflow >> Mass Airflow Sensor turn frequency fail low to 1 and frequency fail high to 2. then in the DTC's tab, turn P0103 to "MIL on First Error"
i'm recommending this to purpose fault out the MAF, which still keeping the temp sensor that's inside the sensor working, and i'm curious how the engine will run when forced in speed density (MAP).
I made a sensor mount for the pre-throttle pressure/temperature sensor. I also have the baro sensor. Next time I fire it up these will be in place and I will have a new O2 sensor. Let's hope that addresses some of this.
It Idles...sort of! Attached is the log file of the 3 minute idle. The new sensors seem to be working. Here are my observations:
1) O2 still not working which eventually causes the same CL fault. I'm at a loss here. I can only imagine that the sensor I have is not the right one. The heater circuit operated normally (visible in log) though which is a good step forward. Ideas?
2) Engine was running rich, I could see puffs of soot as the engine would lump along at certain points. I should be able to sort this out once closed loop works.
3) Engine fans did not turn on despite setting the ignition off limit to 50degrees. I guess this must not work in my configuration. I tested the fans manually and they work so something isn't being triggered to start them. I'll monitor this.
4) Many of the channels look very noisy to me, especially after the CL-fault is tripped. I'm not sure if I need to worry about this or not, just an observation.
So, it looks like I'm still stuck on an O2 issue. I'm at a loss here. I got a new sensor for this start, reset trouble codes before starting, and confirmed manually that the ECM sees a voltage when one is applied. I guess it's time to deep dive O2 sensors....ugghhh.
once you sort out the O2 sensor problem i think you're almost there.
My guess is that you have way too much airflow in the MAF transfer function, guessing 30% to 50% too much, or maybe even more.
personally i think this datafile looks much better than previous ones, but i might be biased. at least RPM is somewhat controlled now as opposed to other files showing 3000 RPM "idle".
Those oscillations aren't noise, they are control system oscillations. they'll settle down once you get the right air measurement.
I finally got the oxygen sensor part number out of AFI. As mentioned before I can?t use the factory regal sensor due to my harness so I needed a different one. I just received it and inspected the heater circuit resistance. It?s ~5.4ohms compared to 3.7 for the sensor I have been using. That is right in line with what my friend told me the regal sensor should be. Tomorrow we will find out if that solves all my issues. What a stupid reason to have this problem. I asked for the sensor p/n so many times...
I gave u the exact part number. If you want the part number for a different model year or car, just ask, I?ll get you those part numbers.
Don?t understand why the harness is dictating the sensor u can use, but if I were u I would have changed the harness to the exact wiring and connector as whatever regal your parts line up with. Was it a 2011?
I don?t think an oxygen sensor is A voltage device so all ur testing with a 1.5v battery probably doesn?t mean anything. I think the ECM provides a fixed current? I?ll have to read up on how o2 sensors work.
Also, since your o2 sensors don?t work, and you don?t seem to want to buy a wide and, just run open loop and guess? I guess?
With all the wiring changes you?ve been through, you may have damaged the ECM. They are very well internally protected, but they?re not indistructable.
To the question what now: what I would do is change the harness to match the wiring and connectors of the car that ur most similar to. If the right wiring and NEW CORRECT O2 sensor still don?t work, I might start looking for another ECM. They should be relatively cheap.
Thanks for the input. I really appreciate the thoughts and time. The harness was not designed by me so I?m relying on the company I bought it from to tell me what sensor it is designed for. The sensor I have now at least has the correct heater circuit resistance and is wired properly. I suppose there remains the possibility that the sensor circuit itself is different. I?ll try to figure out if that is the case. If you have any way to confirm if 12597878 is the same as the regal that would be awesome. It looks to be from 2005-2009 GM V6?s. At least that?s what eBay tells me.
I?m not an O2 expert, but I can tell you that I put a blow torch to a brand new 4-wire Bosch sensor (not a GM part, but by appearance was very similar to the sensor I was using) and read a positive voltage across the sensor. You can find many videos online of people doing the same. My understanding is this is how O2 sensors work. There is a current applied to the heater and it?s possible wide band sensors work that way, but I think O2 sensors generate voltage. I welcome any data you can find to the contrary!
Adding a wide band won?t solve my problem. It will tell me if the MAF is calibrated well, but it won?t allow the ECM to function which is the bigger issue at the moment. I imagine a wide band will be needed to tune WOT, but I?m not there yet.
I really haven?t been through that many wiring changes. I had the original sensor installed backwards which meant the heater was connected to the sensor circuit. After that everything has been correct on the wiring front.
I did reconfirm today that the ECM seed 0V when I put the sensor wire to ground. This still suggest to me the ECM is working. I might need to get a small voltage supply to see if the ECM sees the same voltage I apply.
I?m going to ask AFI for another ECM as well so I can run a test. I guess I?ll also put a blow torch to the newest sensor to see if it produces voltage. If it doesn?t then either it was fried immediately or you may be right that these sensors function differently.
Welp, I just tested the last two O2 sensors and they both generate the expected voltage when heated with a blow torch. I guess it?s time to test the ECM.
I made a video of me doing this test. I?ll post it later in case you are interested.
Just a quick update, I tweaked the MAF calibration and got the car to idle pretty well. I pulled almost 40% fuel to get this. The O2 issue still isn't solved because I've not been able to get another ECM! Hopefully that will be solved soon, but what a PITA.
Last log of reasonable idle is attached in case anyone is interested.
I decided to drive the car around in open loop. This actually worked better than I expected. I was able to drive it on the street well enough to complete my brake and light inspection. I've scheduled my appointment with the BAR (bureau of automotive repair) for the final check before having a street legal car.
I'm not giving up on the closed loop issue however. I bought a simple DC-DC voltage regulator that I'll use to see if the ECM really has an issue and determine if I have a ground issue.
For what it's worth, attached are the first logs from driving around.
Well, for some reason my ECM is reading almost exactly 1v lower than the input voltage (for O2). I apply 1v and get basically zero on the log. I apply 1.5v and get 0.5v on the log. Any ideas?
. Thanks for that. I haven't started the car with it yet, but that will happen next.
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