| Re: TTS Datamster with Wideband questions |
Subject: Re: TTS Datamster with Wideband questions by Steve40th on 2011/4/20 16:30:19 Here is the write up from camaroz28.com "Since I have not seen or heard of any actual information on how to log WBO2 signal thru the stock PCM with Datamaster, I decided to share my knowledge and do a tutorial kind of writeup on this subject, the way I have made it to work. Please note, that I dont take any responsibility for this information, and this is applying to the Innovate LC-1 wideband setup, which has a linear, programmable 0-5V analog output. If you have a different WBO2 controller, you should check for these features, and you should recalculate the equation below with the relevant AFR vs Voltage figures. The purpose of this project is to log RPM and other relevant engine data with WBO2 signal at the same time, in the same program, so it would enable to plot a synchronized AFR vs. RPM table for WOT fueling calibration. There are different ways to log these parameters with so called aux boxes, but since I was too cheap to buy the extra (and way overpriced IMHO) rpm signal stuff, and didnt want to deal with too much extra cables and connections, I decided to give it try thru the stock PCM. So, heres a list of equipment you will need: - OBDI ALDL cable (from akmcables.com or moates.net) - Datamaster EE from TTS (a trial version can be downloaded at ttspowersystems.com) - WBO2 controller with programmable, linear 0-5V analog output. (your choice) - computer (obviously) We need to feed the 0-5V output of the WBO2 controller to a 0-5V analog input in the PCM. The best choice is the A/C pressure sensor, since it is not used for normal engine operation, and most of you have probably already deleted A/C. After you have wired in the wideband controller and it is fully working, hook up the wideband controller analog output signal wire and the analog output ground wire to the relevant A/C pressure sensor connectors. The unused sensor connector can be used for a really clean install. Now comes the tricky part. If you check it in Datamaster, the A/C pressure field will show PSI values which well need to convert to AFR. According to the datastream information for 94-95 LT1 F-cars, byte #30 is for A/D RESULT FROM A/C PRESSURE TRANSDUCER. This byte reports raw data called N which well need to convert first to Volts, then to AFR. Conversion function according to the datastream information is VOLTS = 5N/255, from which we get the integer VOLTS= 0.019608*N. Now, that weve got the conversion of raw data to volts, we need to figure out the relevant AFR values. The default analog output of the LC-1 is 0V=7.35 AFR and 5V=22.39 AFR. Since this is a linear output, we can easily calculate the relevant graph equation, which is AFR=3.008V+7.35. Note: if you have a different wideband controller with different Volts vs AFR relation, you need to calculate the correct linear equation! Replacing V with the integer above, we get AFR=(3.008*0.0196)*N + 7.35 which equals AFR=0.05896*N + 7.35 ; this function will convert raw data N to AFR. Now we need to program and display this information into Datamaster, for which well use the Custom Data feature. Click View > Custom Data. On the Custom Engine Data Display panel, double click on the first row - Check Variable Enabled box, this will enable to display our custom engine data - Byte Number: 30, this is the byte # in the PCM datastream responsible for A/C pressure raw data N - Information: Air / Fuel Ratio, or anything up to you - Variable Name: Wideband O2 - Units: AFR - Gain: 0.05896 ; this is the value from our function above to multiply with raw data N - Offset: 7.35 ; this is the offset value from our function above that is added to the Gain integer - Data Type: INT ; select this as this value is an integer - Display Format: 0.00, this will show values of up to 2 decimals Click OK, you are done! You are now able to see WBO2 AFR and RPM at the same time, with all other engine information. Use your favorite dyno tuning spreadsheets to determine new values for the PE tables. And Link: http://www.camaroz28.com/forums/showthread.php?t=535603 |
