2002CAMAROSSLS1T56

iTrader: (2)

I searched for hours, read for hours. A lot of people have this problem and no one has an answer.

I haven't read anyone actually describing the problem accurately, they typically just say the display seems to read high or low.

My problem is my gauge reads, well different from the hp tuners scanner.

The typical problems I've read are low voltage and bad grounds causing low voltage.

My gauge output reads high voltage. Theres a simple test they have you do where you disconnect the sensor and power it up. The gauge display will read 14.7 and the output voltage will be 2.35

Well my gauge reads 14.7 and the output voltage is 2.47
This is on the hp tuners scanner screen and a DVOM on the output wire.
Thats a difference of .5:1 AFR

Going by the voltage vs AFR chart provided with the gauge, it reads correct on hp tuners scanner I guess.
The voltages and AFR readings coincide consistantly according to their chart.

I don't understand a lot of things with this. I used the standard uncorrected formula of ([PID.2811]/.5)+10 and it's being read through the EGR pin on a 2002 camaro.

According to everything I know this formula should make the reading off since the voltage is higher.

I also pulled the sensor out and tested it with a rag dampened with brake cleaner and with hp tuners connected.
The gauge reads 10:1 at max rich but my scanner reads .14 volts and 10.27 at max rich.
There is no gauge reading at max lean but their chart says it should be 19.98 at 4.99 volts but I'm reading 19.02 at 4.51 volts.

Now I'm wondering why the voltage is high at max rich, but low at max lean.
And whats my AFR? the gauge reading or the hp tuners reading?

And more important, how do I correct this? I've read numerous posts on AEM's website where people have the same problem and send their gauge in only to get a gauge back that does the exact same thing.

Is there any way to correct this with a resistor and narrowing the range in hptuners down to read 11:1 to 17:1?
Right now my range is set from 10 to 20 with a 15 mid.
Would changing any of this help?

black98ws6ta

iTrader: (77)

I have the same problem with AEM wideband's/Hptuners. I have them in several cars and they never match AFR correctly. I was just getting to the point of looking into the problem.

2002CAMAROSSLS1T56

iTrader: (2)

Yea, I thought I'd throw this post up here and see if anyone knew anything about it. I do plan to call their tech support but going by what people have posted on their forum, and various other forums I'm most likely to get the runaround instead of a good old fashioned honest, truthful answer from the manufacturer. That answer would be, we don't know but thanks for your money.

Frost

iTrader: (45)

Logging through EGR further complicates things too... For anyone else reading and thinking of buying a tuning suite, buy the units with their OWN ANALOG INPUTS and run your widebands directly back to your cable for logging.

black98ws6ta

iTrader: (77)

Mine is the EIO version and it still varies. It may be the wideband, or it may be the default table hptuner supplies needs adjusting.

Frost

iTrader: (45)

It's still one less variable to work out.

The PCM uses it's own 5V supply for sensors and reference. Your wideband feed comes from the controller's own supply. You can see the potential for further complication here.

69LT1Bird

iTrader: (1)

Here is the formula I am using with my NGK AFX wideband
100*(([PID.2811]/.7143)+8.9-[SENS.121])/[SENS.121]

2002CAMAROSSLS1T56

iTrader: (2)

Ok then why can I read voltage right off the wide band output with a DVOM, then plug it in a second later and see the same exact voltage displayed as EGR voltage on my laptop screen?
I can also log a run with the gauge output unplugged and read zero output the whole time.

I don't understand your logic here, it was a dead pin once used as a 0to 5 volt voltage carrier for EGR position, EGR has a seperate 5v reference source. Now it's being used for a different gauge, it has the same function, to carry a 0 to 5 volt signal.
It's like taking a length of 16ga wire to carry 12 volts to a dome light, then taking it out and using it to carry 12 volts to a tag light. The wire doesn't "care".

Thats not even the problem, I'm getting higher voltage right out of the gauges output so if I did have HP Tuners EIO interface I'd have the exact same problem.

Nice plug for HP Tuners though.

Another "I don't know" played out as "you've got it connected wrong".

Sorry to be honest and speak what I feel, but your replies have no relevant information. Plus they have a hint of not understanding (as in ignoring the high voltage output, which would be a problem with EIO as well)

Maybe I missed it but you didn't seem to disagree much when this method of reading a wideband was posted on the HPTuners forum 3 years ago.

I'm looking for info, not you should have bought this or that and had the same problem and been able to make the same post about it.

2002CAMAROSSLS1T56

iTrader: (2)

That looks like a AFR percentage error PID to me.

Frost

iTrader: (45)

I pointed that out for the sake of others. I didn't even infer that it was your problem. I had a followup post but have fun with this...

sroach20

iTrader: (31)

http://www.hptuners.com/forum/showth...&highlight=plx
i did 9.9 to make mine match.

2002CAMAROSSLS1T56

iTrader: (2)

That attitude should reel in some customers huh.
A sponsor with a spiteful retort, always good for business.

2002CAMAROSSLS1T56

iTrader: (2)

The problem is the test procedure. They say to disconnect the sensor and the gauge will read 14.7 and the voltage will read 2.35, my voltage reads 2.47

I'm using this formula ([PID.2811]/.5)+10 and it reads correct when compared to their chart

I can change the formula to this ([PID.2811]/.5)+9.76 and it will read 14.7 at 2.47 volts, but it throws all the other numbers off.

69LT1Bird

iTrader: (1)

The 8.9 part of the equation is the thing that matters, like the person above, they did 9.9. The change I suggested was to point out that the NGK digital gauge was reading different than the egr input to the pcm on my setup and I used the formula to synchronize the actual dash mounted gauge that is connected directly to the wideband sensor and the 5v egr circuit thru the pcm.

2002CAMAROSSLS1T56

iTrader: (2)

The change in formula is fairly easy to figure out.
In my case I was reading 14.94 at 2.47 volts, so thats 2.47/.5= 4.94+ 10= 14.94
14.94 - 14.7 = .24
10 - .24 = 9.76

I guess thats the answer to the problem, I don't know.

2002CAMAROSSLS1T56

iTrader: (2)

No, thats not the answer either. Their supplied chart http://i12.photobucket.com/albums/a2...y/aemchart.jpg
is dead on correct with my voltage vs AFR numbers using the formula PID/.5+10

When I enter the corrected formula of PID/.5+9.76 the voltages are off. For example when I look up 2.34 volts, the chart says it should read 14.68 AFR. Now at 2.35 volts it reads 14.47 AFR.

What I don't understand is that the instructions tell you to calibrate their EMS by unplugging the sensor so the gauge reads 14.7 (and mine does) and the voltage reads 2.35 (mine reads 2.47)

So my hptuners scanner reads correct with the wrong voltage, and incorrect when using an offset voltage formula to correct it.

What the hell am I doing wrong?

The scans attached:
SensorTest is with the sensor out using a rag dampened with brake cleaner.
TEST is using the VCM controls to run the engine and manually adjust AFR.

69LT1Bird

iTrader: (1)

Did you do this procedure? It says the output is 2.35 and adjust the gain until that is what shown on the AEM gauge.

"When connecting to AEM’s EMS, make sure to verify that the O2 #1 Gain option is set
so the voltage from the O2 #1 Volts parameter matches the voltage input at the EMS
from the O2 sensor. An easy way to do this is to disconnect the UEGO sensor from the
UEGO gauge. When in this state, the UEGO gauge will output 2.35 volts. You can then
adjust the O2 #1 Gain until the O2 #1 Volts display in AEMPro reads 2.35 volts."

2002CAMAROSSLS1T56

iTrader: (2)

That procedure is for an adjustment on their EMS, not the gauge. The gauge has an adjustment just to switch from:
P0, P1 AEM Gauge default
P2 AFR Small Volt Range
P3 AFR Autronic Emulation
P4 AFR Nernst Emulation

So thats set correctly on my gauge, now if I had an EMS I could just adjust the gain to compensate using the chart for reference.
Sounds easy because the way we are doing it is by changing the calculation formula.

Anyway I just got off the phone with AEM and they basically said to ignore the voltage output reading and their reference chart, and to just set my math so the AFR on the gauge matches the AFR on the laptop (and it'll never be exact)
They said the gauge reads the sensor, and it will be accurate as long as the gauge is good.
The Analog Output voltage will vary depending on many factors, thats why their EMS has a gain adjustment, and we have a math formula. Just adjust it so the gauge reading matches the laptop reading, don't pay so much attention to voltage. And it should be good to go.

They also said to ground it better.

And their chart won't be as accurate using anything other than their equipment.

So when I get a chance I may mess with it some more. I'll probably just take the volt reading off the table display and ignore it.

2002CAMAROSSLS1T56

iTrader: (2)

It's about as close as it's going to get.
http://www.youtube.com/watch?v=5lvgoLaOZMU
Be sure to click on HQ.

jimmyblue

iTrader: (11)

To chase all of the errors out of the system will
take some work. There is at a minimum, a ground
offset voltage. This is variable with the heater
current in-the-moment, sourced and returned
through the WB unit and loading up the ground
path. Heater current varies opposite exhaust gas
temps and with thermal losses (outside air temp,
header construction and so on). A cookbook
correction factor is unlikely to be consistently
right.

One thing to try is, narrowing the AFR range for
the output span. Like, you don't want to run
leaner than 16 or richer than 12? Then make
0.0V be 12:1 (not 10:1) and 4.0V be 16:1
(not 20:1). You've just driven down any ground
and/or gain accuracy errors by 2.5X. You have to
sync up the WB and HPTuners PID for custom,
of course.

The downside would be, if you are operating with
mixtures presently outside this span, your "AFR
Error %" which a lot of the "easy way" table-tweak
methods count on, may be truncated and you may
end up taking multiple passes through the process
(like, you didn't see it was really 11:1 at WOT so
you only correct for 12:1 -> 12.8:1; next time you
see 12:1 again and correct; third time it's 12.2:1
and at least you're in sane range so the correction
is finally right, not a half-measure).

Your other option is hardware cobbling. Like build
a little, floating-bias instrumentation amplifier
board that communicates your WB output difference-
to-WB-ground, to an EIO difference-to-EIO-ground
signal. Cheap, doable (if you like soldering), need
a couple of 9V batteries to run it. Worth it? I dunno,
I built one, it does the job, but for a decimal point
or two I seldom bother pulling it out of the bag and
replacing the now-dead batteries.