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Just installed new headers (1 7/8 OBX) and wanted to log my wideband.
AEM wideband 30-4900 connected through a/c pressure sensor.
Tried to use this formula ([7101.10]/.5)+10 and got readings that differ from what I see on a WB device.
HP shows around 20, WB shows 13.-15.
AC pressure sensor voltage itself (WB output to PCM) stays at almost 5v level all the time, which means that formula is correct.
Does anybody have an idea what I'm doing wrong?
Guys,
I found where I did a mistake and want to share my experience to CF.
I believe this info will be useful for those who use AEM Failsafe device 30-4900.
As was mentioned in the first post I need to connect Analog Output 5v from a device to 2-pole switch (when connected through AC). In case of AEM it is white wire, that is going from the device. But brown wire (ground from device) should be connected too, other way you will get only 5v signal (see previous post). So connect a brown wire to reliable ground and you'll get proper signal.
Function for AEM Failsafe 30-4900 AFR (Gas) = (2.375 * Volts) + 7.3125
Just curious on the LC2 if you would still need to input a formula in HP tuners since it includes LM programmer where you can alter the programming of the Analog 2 which has the narrowband (1.1v for 14AFR and .1V for AFR15)? Thanks!
Yes, LC2 (just like LC1 or MTXL) has 2 analog outputs, both of which you can set any Lambda vs voltage table, among other settings. HPtuners is just going to see some sort of voltage coming in either way, regardless of what kind of wideband you're using.. you gotta let hptuners know what to make of this signal.
I wrote this a while back just for personal information. This is based on HP Tuners.
UPDATED
Reading a Wideband through the EGR or A/C Pressure Switch
EGR
• The EGR wire is located at Pin 55 on the Blue connector of the PCM (NOTE: on the 97-98 Corvettes this will be Pin 9 on the Blue connector).
• On vehicles that come with an EGR (Camaro's, etc.), there will be a Brown wire at Pin 55, it is designated “EGR Pintle Position Sensor Signal” in a pinout schematic.
• If your vehicle did not come equipped with an EGR (Corvette), there will not be a wire and the schematic will say "Not Used". Just add a wire to the PCM at Pin 55 (or 9), everything still works the same. I went to a junkyard and found a plug under the hood of a GM vehicle with the same type of ends as the PCM wires. Click here for instructions on how to gain access to your PCM.
• Connect the Wideband 02 wire with the 0-5v output to the EGR wire at Pin 55(or 9). This may be all you need to do with some widebands, some others require a ground. Check the wiring schematic for your specific unit.
A/C Pressure Switch
• There are 3 wires connected to the A/C Pressure sensor. The Red wire with Black stripe that is going to the PCM is the one we want to use. You can go to a junkyard and find another connector to plug into this so you can switch back and forth or you can buy a Maintain switch that, when you switch it one way it reads from the A/C sensor and when switched the other way, it reads from the Wideband O2 output wire. Either way will work fine, so that you can easily put it back to normal when you are done tuning.
HP Tuner Scanner
• Now that the wiring is done, you need to set it up in HP Tuners. You will need some information on your specific wideband that will be in the widebands paperwork. You will have to set up a formula to change the voltage (0-5v) into your AFR wideband reading. It will look like this:
VOLTS / (VOLTAGE RANGE/DEVICE RANGE) + (MINIMUM VALUE OF DEVICE READING) = AFR
VOLTS = the voltage that the wideband 02 sensor is putting out to the EGR wire
VOLTAGE RANGE = typically 5v (0-5v), some people use the narrowband 02 input (not recommended) which is 1v (0-1v)
DEVICE RANGE = the range your wideband is set to read. If the wideband is set to read from 10 – 20 AFR, then the range will be 10. If set to read from 8 – 22 AFR, the range will be 14, etc.
MINIMUM VALUE OF DEVICE READING = the lowest number that your wideband is set to read. In the above examples, it would be 10 for the first example, and 8 for the second.
I am using a PLX SM-AFR 250 that is set to read AFR from 10-20, so I will use it for my example. The formula will be:
VOLTS / (5/10) + 10 = AFR or,
(VOLTS / .5) + 10 = AFR
• Since HP Tuners Scanner will be using the EGR or AC Pressure switch to get its readings from, we need to add that into the formula. The PID for the EGR on LS1 based cars is PID.2811(EGR Position). Now the formula reads like this:
([PID.2811]/.5)+10 = AFR
• The formula for the A/C Pressure switch is the same, you will just have to change the PID to PID.7101.
([PID.7101]/.5)+10 = AFR
Custom PID
• Open Table Display in VCM Scanner
• Right click any blank line and choose Insert
• This will open the Insert PIDs display
• Here you will see PID List, AUX Input List and User Defined. Click the + next to User Defined to open the drop down list
• Double click Configure User Defined to open Configure User Defined Parameters
• Click on one of the numbers with <undefined> next to it
• For Name:, put the name of your choice, say, Air Fuel Ratio
• For Abbrv:, put AFR
• For Sensor:, open the drop down box and choose "None"
• For Units:, open the drop down box and choose ":1"
• Under Function:, insert your formula. For EGR it is ([PID.2811]/.5)+10
• If you are using the A/C Pressure switch, use the formula: ([PID.7101]/.5)+10
• That’s it, just click the Up Arrow to commit changes, then click the X at the top right to close the box and click the Save icon on the Histogram Configuration page.
• To make a custom PID for AFR % Error make your way back to the Configure User Defined parameters page. There will already be an Air Fuel Ratio Error PID. Open it and look at the information in the Function box.
• Copy this formula EXACTLY. It will look like this:
100*([SENS.120]-[SENS.121])/[SENS.121]
• Since SENS.120 is the AFR SENSOR we want to create a new Custom PID and substitute our new formula in place of SENS.120, then enter this into the Function box. Now it will look like this:
100*((([PID.2811]/.5)+10)-[SENS.121])/[SENS.121] or
100*((([PID.7101]/.5)+10)-[SENS.121])/[SENS.121] for the A/C Pressure switch. If you have trouble, double check all your parenthesis. It is best to copy/paste this formula.
• On this Custom PID, give it a name, use AFR%Error for the Abbrv, leave Sensor blank, and use % for Units.
• Now, you can change the information in your VE and MAF Histograms to use the custom PIDs that you just made.
• ATTENTION: In Editor (Engine/General), you have to enable EGR. Also, don’t forget that each of these below will have to be logged in Table Display:
- EGR Position, if your are using EGR Pinout 55 (or 9). Located: (PID List/Engine/Emissions/EGR Position (V))
- A/C Pressure, if you are using the A/C Pressure switch. Located: (PID List/System/AC/AC Pressure (V))
- AFR
- AFR % Error
- AFR Commanded
How do i wire in a dual wide band 1 in egr n the other into a/c ??
Guys,
I found where I did a mistake and want to share my experience to CF.
I believe this info will be useful for those who use AEM Failsafe device 30-4900.
As was mentioned in the first post I need to connect Analog Output 5v from a device to 2-pole switch (when connected through AC). In case of AEM it is white wire, that is going from the device. But brown wire (ground from device) should be connected too, other way you will get only 5v signal (see previous post). So connect a brown wire to reliable ground and you'll get proper signal.
Function for AEM Failsafe 30-4900 AFR (Gas) = (2.375 * Volts) + 7.3125
Hope this helps.
Vasiliy
Sorry to revive an old thread, but well if it's a 'sticky' I don't think I'm hurting the thread too much. I have the same issue of the constant 5V reading on HP tuners from the "AC pressure sensor" when wired up to my wideband, in my case it's an AEM X Series 30-0300. I used a 2 position toggle switch, and wired the "red wire with black stripes" from AC sensor harness to the white wire of AEM (+0-5V) and the brown wire (0-5V sensor ground) to a body ground by the BCM underneath the passenger footwell. If the toggle switch is switched for the AC sensor, my AC works perfect, but when switched to the wideband, it just reads constant 5V. I don't get it. Where do I wire the brown wire from the AEM X series wideband?
I have not done this yet but if you look closely you need to wire in the sensor ground to the ground of the AC pressure switch. The body ground and the sensor ground are 2 different grounds. That should be the reason for your constant 5 volts.
Finally got around to installing the wideband. FYI its the AEM 30-0300. The above info was extremely helpful in pointing me to the right direction but some of it is out of date due to upgraded software so I will give my way that i did it. This doesnt mean my way is the right way but its just the way I did it.
Mounting the sensor
I have the stock exhaust so I had a bung cut and welded into the H pipe on the drivers side before the pup cat. Plenty of room and ran the wire up the cavity where the wiring is for the windshield so its outside of the engine bay and away from heat and the steering column. Ran across the engine bay zip tying to the hood release cable.
Running the wiring
Pulled the panels from underneath the glove box, covering the BCM and fuse box and on the passenger side of the center console. There is a small wire bundle that comes into the cabin from the engine bay from behind the battery so that was also pulled. Not to be confused with the larger bundle behind the battery. The one I used is above that one. Pushed both wire bundles through the grommet so everything stays somewhat weather tight. I bought a cheap cup mount gauge holder that I am going to mount to the cup holder lid on the center console. Opened the ashtray lid and removed the ashtray and pulled the wires through to there.
Attaching the wires
Both wire bundles plug into the back of the gauge. The wires for the sensor were already connected and run through the engine bay so nothing more to do there. Now there are only 4 more wires to attach. Since the wires are run so close to the interior fuse box the red power lead was attached to a fused power tap and plugged into a empty fuse slot. The cover for the fuse box is open on the top so passing the wire thru the top is not big deal. There is a metal panel behind the glove box so I just attached a eyelet to the black ground wire and used a self tapping screw to attach it to this panel. The next 2 wires will need to be lengthened to attach to viable points. The brown sensor ground wire was attached to the ground for the AC pressure sensor, I will look into where the wire can be tapped into in the BCM at a later date so it will be one less wire into the engine bay. Lastly the white wire needs to be attached to either the AC pressure sensor or the ECM EGR input. I started to hook it into the AC pressure sensor but when I was done decided that it wasnt what i wanted. After jacking up the passenger side and removing the front wheel, the panel covering the ECM was removed. I pulled the blue connector from the ECM and opened up the guide in order to add a pin. As a side note, I have worked and rewired a few cars in the past and had some pinned connectors left over. They were not compatible with the current connector but with a slight modification it slid right in from the front. Reinstalled the guide, passed the new wire up into the battery area and reassembled all the removed parts. Connected this wire to the white wire and all was good. At this point I just turned the key to see if the gauge was working and low and behold it cycled. Takes a while for the gauge to register due to the sensor heating up but it does work.
HPT editor
At this point the above info is somewhat out of date so I will give examples of how I made it all work together using the current software. In the Editor you have to enable the EGR port. After starting the program click on "edit" then "navigator". When the box pops up you will click on "exhaust" then "gas recirculation" then "general" and finally "EGR enable". Change the box from disabled to enabled and close the boxes. Upload the new tune to the ECM and this part is complete.
HPT scanner
This part is a little more complicated in a way but after you figure it out its really easy. After opening the scanner without it connected to the car I started by adding a channel for the EGR pin. Even though it is now used for the wideband, you can use this to monitor the voltage being reported to the ECM. Right click on a empty slot and click on "add channel". Then click "engine" then "exhaust" then "gas recirculation" and finally double click "EGR sensor" and youre done. You can close the box.
Next I added a line in the chart to see the wideband value. This took a little trial and error but I was able to get it to work. Right click anywhere on the "chart vs time" area then click on "chart layout". Pick a group and position and single click on the area. Click "add series". Click on the parameter link and you will again see a drop down menu. Enter a "label" that you want to call this in the chart. Go to "maths" then "user defined" and finally "wideband". Click on that and the box will close and be selected. Adjust the limits according to the wideband paperwork. For me it was a low of 8.5 and a high of 18. Enable the reference line, pick a plot color and youre done with this section. Save the layout and close the box. One more step to go.
Now we just need to add in the math to make the sensor display properly. The formula should again be found in the paperwork that came with the wideband. From the main menu click on "tools" then "math parameters". a new window will pop up. With the new software they make setting up this part almost plug and play. Click on "user math1". Click on "new variable" on the right side and another box will open. Click on the "parameter" link and yet another box will open. Scroll down to "fx transforms" then "oxygen sensors" then " air fuel ratio". Click on your sensor then just click on "yes sounds good". Some boxes will close. Leave special functions to none and click OK. Under unit click on the appropriate air fuel ratio, in this case gasoline. In "expression" clear out anything in there and enter in the formula you got from the paperwork. In my case this is the formula.
(2.3750*[2811.10])+7.2125
You will notice the value in the [ ] represents the sensor being used. In this case the EGR sensor. If you are using the AC pressure sensor input then I believe you just change the 2811 to 7101 or whatever the sensor ID number is. Name, abbreviation and notes you can enter anything you want. Save the math parameters and youre done.
Save the whole scanner layout and you should be good to go.
Sorry for the lack of pictures. If there is enough interest I can take things apart and snap a few. Hopefully this will help someone in the future until the next software incarnation makes it obsolete.
04-10-2016, 01:59 AM
Need help
