$DA ECM DEFINITION FILE

Transcription

1 $DA ECM DEFINITION FILE OVERVIEW This document is intended to familiarize you with the features of C.A.T.S. Tuner Program. We do not attempt to provide instruction on engine tuning. The features provided are based on extensive experience tuning engines ranging from stock to extensively modified. We feel that we have provided the appropriate tuning functions to handle most conditions, including obtaining emissions certification. The following information describes the various switches, constants and calibration tables. SWITCH TABLE The following switch settings can be modified. VATS Diagnostic The VATS diagnostic mode may be shut off to prevent the VATS system from preventing fuel injection. CONSTANTS TABLE The following constant values can be edited with the Tuner program. Fuel Cutoff (Speed) Fuel Cutoff, 1st Gear (Eng. Speed) Fuel Cutoff, 2nd Gear (Eng. Speed) Fuel Cutoff, 3rd -> 6th Gear (Eng. Speed) Fuel Resume (Speed) Fuel Resume, 1st Gear (Eng. Speed) Fuel Resume, 2nd Gear (Eng. Speed) Fuel Resume, 3rd -> 6th Gear (Eng. Speed) Fuel off and resume values make up an engine and vehicle speed limiter. These values are hysteresis pairs. Fan 1 On, Low MPH Fan 1 On, High MPH Fan 2 On, Low MPH Fan 2 On, High MPH Fan operating point thresholds for fan 1 and fan 2, in degrees C. These values are hysteresis pairs. PAGE 1

2 Fan Low MPH Hysteresis Fan Low MPH Hysteresis The low and high speed hysteresis modify the fans trip points at very low speed and very high speed. Injector Flow Rate, #/Hr The injector flow rate is for a single injector, total fuel flow values may be obtained by multiplying the #/hr value by the number of injectors. This value should be changed if the fuel injectors are replaced with higher or lower flow rate injectors. Cylinder Volume ml/cylinder Cylinder volume is expressed in ml/cylinder. To obtain total displacement multiply by the number of cylinders. To calculate displacement in liters multiply ml x 100 To calculate displacement in cu in multiply ml x The following EGR enable qualifiers set up the operating window for EGR operation. The window uses %TPS, RPM, MPH and MAP. EGR Off, (%TPS) EGR On, (%TPS) EGR enable TPS hysteresis pair, low end of EGR enable. EGR Window, Low RPM Window, Off RPM EGR Window, Low RPM Window, On RPM EGR enable RPM hysteresis pair, low end of EGR enable. EGR Window, High RPM Window, Off RPM EGR Window, High RPM Window, On RPM EGR enable RPM hysteresis pair, high end of EGR enable EGR Window, Low MAP Window, Off MAP EGR Window, Low MAP Window, On MAP EGR enable MAP hysteresis pair, low end of EGR enable EGR WINDOW, High MAP Window, Off MAP EGR WINDOW, High MAP Window, Off MAP EGR enable MAP hysteresis pair, high end of EGR enable Main Spark Advance Vs RPM Vs Load The Main spark table is a function of manifold pressure and RPM. This table is used above idle and up to 4000 RPM. PAGE 2

3 Main Spark Advance Vs RPM Vs Load (Ext.) The extended spark table is a function of manifold pressure and RPM. This table is used above 4000 RPM. Closed TPS Spark Advance Vs RPM This table is used at or near idle RPM Max Knock Retard Vs. RPM Table of spark retard maximum limits that may be applied if knock is detected as a function of current engine RPM at or near wide open throttle, (WOT). Max Knock Retard Vs. MAP Table of spark retard maximum limits that may be applied if knock is detected as a function of current engine manifold pressure, (MAP), NOT AT (WOT). Volumetric Efficiency Vs. RPM Vs. Map This table is the main fuel table and is in us up to 2000 RPM. Values shown are volumetric efficiency Vs. RPM and manifold pressure, (MAP) Volumetric Efficiency Vs. RPM Vs. Map (Ext.) This table is the extension to the main fuel table. It is used from 2000 RPM and up. Values shown are volumetric efficiency Vs. RPM and manifold pressure, (MAP) TPS Threshold Vs. RPM For WOT Table of differential percent throttle position thresholds to enable wide open throttle conditions Vs. RPM. WOT %Change To AFR Vs. Coolant Temp. This table is percent change to Air Fuel Ratio used at or near wide open throttle (WOT) Vs coolant. The values from this table and the WOT %Change To AFR Vs. RPM are summed to arrive at the WOT Air Fuel ratio. Approximate air fuel ratios may be calculated using the method shown below. WOT %Change To AFR Vs. RPM This table is percent change to Air Fuel Ratio used at or near wide open throttle conditions Vs. RPM. AFR is based on 14.7:1. The values from this table and the WOT %Change To AFR Vs. Coolant Temperature are summed to arrive at the WOT Air Fuel ratio. Approximate air fuel ratios may be calculated by the following method: Assume: RPM = 2000 Therefore table value = PAGE 3

4 Coolant = 80 Deg c Therefore table value = 22.7 (1- ( )/100) * 14.7 = 12.2:1 AFR Open Loop %Change To AFR Vs. Coolant Temp. Open loop Air Fuel Ratio percent change vs. coolant temperature based on standard AFR of Approximate air fuel ratios may be calculated as shown below. Assume: Coolant = 80 Deg C therefore table value = 14.8 (1- (14.8)/100) * 14.7 = 12.5:1 AFR Target Idle RPM Vs. Coolant Temp. The ECM will attempt to maintain the RPM in this table, +/- 25 RPM when the vehicle is in drive. Idle RPM Adder Vs. Coolant Temp. This table contains an RPM value that is added to the target idle RPM when the vehicle is in Part/Neutral. PAGE 4

5 USEFUL INFORMATION AND REFERENCE MATERIAL MAP MAP stands for manifold air pressure, this measured in Kpa, (kilo Pascal) is a metric unit of force). Because fuel and spark are very dependent on this value it must be as accurate as possible, 1 Kpa = in hg. Traditionally we have used engine vacuum for this function, but vacuum is measured relative to local atmospheric pressure where as MAP is measured in absolute terms, (relative to absolute vacuum). The result is that we account for atmospheric changes in our measurement. To convert vacuum to Kpa subtract the vacuum value from local barometer (standard is in hg). For example in hg - 15 in hg = in hg MAP (or 51 Kpa MAP) Full load MAP is at or near 100 Kpa, (29.95 in hg), and idle is about Kpa, (9-12 in hg) Coolant Temperature Coolant temperature is measured by a separate more accurate sensor than the instrument panel sensor. Values are in degrees C, since that is the way the ECM/PCM uses them. %TPS This is the percentage of full throttle travel, some SCAN tools show this value as a voltage; a value from near zero to 4.9 VDC. To convert voltage to percent, divide observed voltage by 4.9. Some tables use differential %TPS as a scale. This is the TPS observed earlier, subtracted from the current value of TPS. Example: if you go from cruise to floor it the old value would be 20%, the WOT value is now the current value, say 99%, therefore the differential TPS is 79%. Volumetric Efficiency Fuel delivery is based on the amount of air consumed by the engine to maintain a 14.7:1 Air Fuel Ratio. One pound of fuel is required for every 14.7 pounds of air consumed. Speed density fuel systems use cylinder volume, RPM and temperature to estimate the air consumption of the engine. The volumetric efficiency tables correct the air estimates for a better match to the actual engine air consumption. The result is applied to the injector flow calibration to arrive at the required injector duty cycle for the correct amount of fuel to be delivered to the engine. These fuel predictions have a correction factor applied as a result of the O 2 sensor feed back information. The closer we can predict the correct fuel delivery, (small correction from O 2 ), the better the engine will perform, particularly transient conditions. Hysteresis Pairs Some of the constant values are hysteresis pairs. This technique is used to keep enables from bouncing in and out of a specific condition due to small variations. For example if something is supposed to happen when the TPS has reached 50%, we will set an enable threshold at 50% and a disable at 48%, this is a 2% hysteresis. PAGE 5