Trouble Code Definitions
Codes not adding up
- Thread starter abrad
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Don’t know what you mean by wide band sensor.
I will run all that data tonite when I get home, then post pictures of what is showing.
At this point, I’m just going claim senility, cause this is my first time dealing with this type of technical bs…
I will run all that data tonite when I get home, then post pictures of what is showing.
At this point, I’m just going claim senility, cause this is my first time dealing with this type of technical bs…
Ok, here’s the complete list, 4 screens worth.
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These 5 are the various ones (description upper left corner) running on the graph function. On the O2, sensor 1, you can see the negative numbers…
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I have the original MAF currently installed, as it’s the only one that will allow idle. At some point it will throw a P0171 code, that’s why I was thinking bad MAF…. I’ve cleaned it with electric parts cleaner, wiped it with a q-tip, and that damn code kept coming back! Used to have that problem on an old Toyota, if cleaning didn’t fix it, a new sensor did.
If the swing is between .1 and .9 it's a standard ZI O2 sensor. Wideband allow for a leaner fuel control and are different in the way they work.
Yeah, the flat IAT caught my eye , too. And, it is kind of low fro an under-hood temp. Was the engine fairly cold when that data was taken?
Can I assume that most previous data (859 rpm, 38kPA MAP, 32C IAT, 2.37 g/s MAF) were all taken at virtually the same time? If so, the MAF is low. I calculate it should be about 8 g/s.
When I calculate MAF I have to make some simplifying estimates, am working mostly in my head. Yes, I use a calculator for the actual math operations, but am stringing the equations and conversion factors mostly mentally. Point is, I may be making mistakes. If somebody who has actual data from properly-operating engines can post some typical data, it would be a good sanity-check for us.
In the meanwhile, every time I calculate MAF from your data, it comes up considerably different than the MAF reported by you. Since the MAF differences seem to change when you change MAF sensors, I have to be more suspicious of the sensors than anything else (wiring or PCM) in the MAF system. That "flatlined" IAT is also a hint. You need to try another MAF sensor. It is entirely possible that the first two replacements where bad. From now on, for any MAF sensor you try I would like to see concurrent rpm, MAP, IAT, and MAF readings. If you have to take your second MAF replacement back to get a third, put that second one back on and record data from it before returning it.
I noticed from the screen-shots that MAP is, indeed, in kPa, not gPa. You must prevent posting bogus data of any kind; it will cripple our efforts to help you. It may seem like a trivial typo, writing "p" instead of "k', but putting a decimal-point off one position, or typing a "1" instead of a "9", can send us way out in the weeds. My apologies if it sounds like I'm picking on you, but this long-distance diagnosis process is a prime example of "garbage in, garbage out"!
I also noticed that you were correct in reporting O2 readings as mA. That makes no sense, and I could find no explanation in the AL619 manual I found online. I, too, believe this is a NB sensor, and would like to ignore the O2 stuff until we are confident the MAF readings are reasonable. Do you still want details on the difference between NB and WB sensors?
Can I assume that most previous data (859 rpm, 38kPA MAP, 32C IAT, 2.37 g/s MAF) were all taken at virtually the same time? If so, the MAF is low. I calculate it should be about 8 g/s.
When I calculate MAF I have to make some simplifying estimates, am working mostly in my head. Yes, I use a calculator for the actual math operations, but am stringing the equations and conversion factors mostly mentally. Point is, I may be making mistakes. If somebody who has actual data from properly-operating engines can post some typical data, it would be a good sanity-check for us.
In the meanwhile, every time I calculate MAF from your data, it comes up considerably different than the MAF reported by you. Since the MAF differences seem to change when you change MAF sensors, I have to be more suspicious of the sensors than anything else (wiring or PCM) in the MAF system. That "flatlined" IAT is also a hint. You need to try another MAF sensor. It is entirely possible that the first two replacements where bad. From now on, for any MAF sensor you try I would like to see concurrent rpm, MAP, IAT, and MAF readings. If you have to take your second MAF replacement back to get a third, put that second one back on and record data from it before returning it.
I noticed from the screen-shots that MAP is, indeed, in kPa, not gPa. You must prevent posting bogus data of any kind; it will cripple our efforts to help you. It may seem like a trivial typo, writing "p" instead of "k', but putting a decimal-point off one position, or typing a "1" instead of a "9", can send us way out in the weeds. My apologies if it sounds like I'm picking on you, but this long-distance diagnosis process is a prime example of "garbage in, garbage out"!
I also noticed that you were correct in reporting O2 readings as mA. That makes no sense, and I could find no explanation in the AL619 manual I found online. I, too, believe this is a NB sensor, and would like to ignore the O2 stuff until we are confident the MAF readings are reasonable. Do you still want details on the difference between NB and WB sensors?
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Yes, each group of figures were taken at the same time. This latest group, with pictures, were taken on a cold engine. Sorry about the mis-typing. Damn phone likes to autocorrect like crazy, which has led to some interesting texts… especially when you using voice to text!
When I look up the upstream O2 on Rockauto, it shows a 4 pin setup. At some point, hopefully this weekend, I plan to crawl under and check the readings on the harness. I found a page that says the ohm resistance should be 10 to 40 Ω of resistance on pins 3 & 4. Does that sound correct?
When running the graph, I’ll do both MAF’s in sequence - old then replacement. Should the engine be warmed up first, or does that matter? Anything else for me to be checking while I’m at it.
Before you start the engine, while it is fully cold, read IAT, ECT, and trans fluid temperature. All three should be close to each other, and close to what the ambient temperature where the car has been sitting. Then do the same using the other MAF sensor. You do not have to fully swap the MAF sensors to do this, just unplug the harness and connect to the other sensor; but let the other sensor being tried sit on/near the engine for a few minutes to stabilize at the engine's ambient temp.
10-40 ohms for a NB heater sounds about right, although I think it would be close to the 10 ohm end of the range. I really don't know what the pin numbers are. I think they (NB sensors) are very standardized, so any info you found is likely correct.
I suggest you contact Autel and ask what that goofy "mA" (and negative values!) for O2 mean; but I don't think your problem is with the O2 stuff..
10-40 ohms for a NB heater sounds about right, although I think it would be close to the 10 ohm end of the range. I really don't know what the pin numbers are. I think they (NB sensors) are very standardized, so any info you found is likely correct.
I suggest you contact Autel and ask what that goofy "mA" (and negative values!) for O2 mean; but I don't think your problem is with the O2 stuff..
Looked up mA - supposedly means milli ampere, one thousandth of an amp!
Now, as requested -first phot is old sensor, second is the Cardone sensor
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Then, I switched over from metric to English.
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Well, the two MAF sensors are showing IAT values close to each other, but neither is close to the ECT. I would expect IAT and ECT to agree within +/- 5F, at worst. Had the car been sitting in sunshine previous to these readings? Sunshine will start raising the under-hood/intake temperature faster than the engine coolant. The IAT/ECT comparison is best done in the early morning, after everything has stabilized at the same temp for several hours.
If those 102/104F IAT readings are bogus, not accurate for what temp the MAFs are really, then we are back to suspecting wiring or the PCM.
Yes, I know "mA" means milliamps. What I don't have, is any clue about how those values Autel reports relate to AFR/lambda. NB sensors, which I think you have, are always reported as voltage, since they "toggle" from lean to rich at 450mV. WB sensors are reported in AFR or lambda; and usually have the 0-1V NB output synthesized for applications or scanners that can't handle WB data. Milliamps is a bizarre (useless?) way to report O2 sensor readings, so I would be curious what Autel thinks it means. However, I don't think your problem is with the O2 sensing, so probably not worth the bother to find out Autel means.
If those 102/104F IAT readings are bogus, not accurate for what temp the MAFs are really, then we are back to suspecting wiring or the PCM.
Yes, I know "mA" means milliamps. What I don't have, is any clue about how those values Autel reports relate to AFR/lambda. NB sensors, which I think you have, are always reported as voltage, since they "toggle" from lean to rich at 450mV. WB sensors are reported in AFR or lambda; and usually have the 0-1V NB output synthesized for applications or scanners that can't handle WB data. Milliamps is a bizarre (useless?) way to report O2 sensor readings, so I would be curious what Autel thinks it means. However, I don't think your problem is with the O2 sensing, so probably not worth the bother to find out Autel means.
That is not a valid output of any O2 sensor. They are all voltage signals.