Help with AEM 0300 set up math

[2000ss]

Hello 99 Camaro
I installed a Aem 30-0300 using the EGR port (blue55 and red41)
The gauge I assume is reading correctly but for the life of me cannot get the scanner to read the same or even close to the same as my WB.
The scanner is reading about a little more than double of what my WB is saying.

wb.png

error.png

wbs.png

wbx.png

[gtstorey]

How did you come up with that formula for AFR? The manual for that gauge gives AFR=(2.3750xV)+7.3125
https://images.carid.com/aem/custom-...ion-manual.pdf Page 10.

[2000ss]

How did you come up with that formula for AFR? The manual for that gauge gives AFR=(2.3750xV)+7.3125
https://images.carid.com/aem/custom-...ion-manual.pdf Page 10.

from one of the threads here on hptuners

when i try that formula it gives me -50 across the board in the scanner im going to try again


like this right
(2.3750*[2811.10])+7.3125

just noticed after i tried this time my egr volts in my scanner are showing 0v

[gtstorey]

Monitor your EGR pid. Your voltage would have to be -24v to get -50 from that formula.

[2000ss]

so i tried again with how i wrote the formula out and Screenshot 2023-04-20 150257.png
this is what i get now

i have the EGR sensor pid in my channels

[2000ss]

https://www.youtube.com/watch?v=SMEmvtgy2M0
i referenced this video do to him doing the same method as me and still no luck
i even grounded the brown wire to a straight to the battery still no luck

[gtstorey]

What is the egr voltage?

[Hondaeater]

Create another User math, Use the EQ ratio equation from manual pg 10. See if you get what's on gauge.
Do you get the same value even though not same as WB gauge, but EQUAL value like the analog output scaling table on page 10 .... WB EGR Lambda channel vs WB EGR AFR channel?
If not, which User Math is closer to gauge reading in the chart vs time?

[2000ss]

What is the egr voltage?

Still 0v

Create another User math, Use the EQ ratio equation from manual pg 10. See if you get what's on gauge.
Do you get the same value even though not same as WB gauge, but EQUAL value like the analog output scaling table on page 10 .... WB EGR Lambda channel vs WB EGR AFR channel?
If not, which User Math is closer to gauge reading in the chart vs time?

if i do it the way from page 10 it shows like 8.5 in the chart vs time ......WB EGR Lambda channel vs WB EGR AFR channel i didnt see this in the channel list

and either way i put it in the user math (2.3750*v) + 7.3125 or [2811.10]*2.3750+7.3125 both give me the same results

[2000ss]

so i connected it to the AC pressure switch red wire and grounded to the battery im getting closer now WB is reading 18.3 key on engine off and now scanner is reading about 17.23 xx.png

this is the math im using so far and i know my error math is way out of line also
xl.png

[Hondaeater]

I mis-typed, it's not a "channel" it's a chart vs time parameter but you need to make both user maths, 1 AFR and 1 for lambda. compare values reported in the chart. Return back to the page 10 of the manual in the analog output scaling table it's on page 10 it's to the right of the equations. So either match the WB gauge?

[gtstorey]

I don’t think this is a math problem, it’s a voltage problem. Check the output of the gauge/controller with a voltmeter.

[2000ss]

I mis-typed, it's not a "channel" it's a chart vs time parameter but you need to make both user maths, 1 AFR and 1 for lambda. compare values reported in the chart. Return back to the page 10 of the manual in the analog output scaling table it's on page 10 it's to the right of the equations. So either match the WB gauge?

now after i went to the muffler shop and had them install a permanent o2 bung instead of just the one on my longtubes the sensor and the scanner are very close maybe my cpu is just polling slower than my wide band is, i made a video to compare my gauge vs my scanner and its spot on and within +/- .1-6

I don’t think this is a math problem, it’s a voltage problem. Check the output of the gauge/controller with a voltmeter.

am i suppose to get constant 5v from the ac pressure switch ? red wire

[gtstorey]

am i suppose to get constant 5v from the ac pressure switch ? red wire

You should get 5v on a wire but I don't have a wiring diagram for your vehicle to say what color it should be. Don't hook the gauge output to the 5v wire. If it's a 3 wire AC pressure sensor, hook it to the other 2 wires (pressure sensor signal and low reference/ECM ground).

[2000ss]

so i looked it up for my car and it goes

14 RED/BLK A/C Refrigerant Pressure signal (A/C)
80 BLK Low Reference (A/C)
45 GRY 5 Volt Reference (A/C

so i should hook my ground to the low ref ground instead of straight to the batt

i already have the white wire going to the red signal wire

[gtstorey]

I’ve heard claims for using both the main ground and the low reference ground. I’m pretty sure the AEM instructions say to use the low ref ECM ground when available.

[Hondaeater]

i made a video to compare my gauge vs my scanner and its spot on and within +/- .1-6
I'm glad that's working out.Did you create both user maths?
1afr
1 lambda? I have had issues where lambda was spot on with gauge, but afr chart was off.

[gtstorey]

I’ve heard claims for using both the main ground and the low reference ground. I’m pretty sure the AEM instructions say to use the low ref ECM ground when available.

"the BROWN
wire must be connected to the negative of the analog input
of the logging device or ECU. If the logging device or ECU
does not have a differential analog input (both a dedicated
positive and negative terminal for the analog input) then
connect the BROWN wire to the shared signal ground. If
the device does not have a dedicated signal ground then
as a last course of action, connect it to the power ground
of the logging device."

[2000ss]

i made a video to compare my gauge vs my scanner and its spot on and within +/- .1-6
I'm glad that's working out.Did you create both user maths?
1afr
1 lambda? I have had issues where lambda was spot on with gauge, but afr chart was off.

not yet im going to try the math for lambda today last night i was stumped with it not working 100% correctly

so basically i would the same formula but just the math for lambda instead right ? (0.1621* [7101.10] + 0.4990 ... never used one of these so this is all new to me

"the BROWN
wire must be connected to the negative of the analog input
of the logging device or ECU. If the logging device or ECU
does not have a differential analog input (both a dedicated
positive and negative terminal for the analog input) then
connect the BROWN wire to the shared signal ground. If
the device does not have a dedicated signal ground then
as a last course of action, connect it to the power ground
of the logging device."

Nice ok i will swap it over to the low reference because its there so i might as well use it also see if that helps also

[gtstorey]

I'm not sure how the same voltage could give you more accurate readings on Lambda or AFR. The Lambda formula is the same as the AFR formula divided by 14.65.

(2.3750xV+7.3125)/14.65 = 2.3750/14.64xV+7.3215/14.65 = 0.1621xV+0.4990

However the error will appear smaller in Lambda.