EFI Dictionary

GearHead-EFI members project EFI dictionary help needed!

Common fuel injection and tuning terms defined (beta version) here:
http://www.gearhead-efi.com/gm-ecm-p...ictionary.html

Ok, in response to the documentation thread, here is my beta version of a noobs guide of common terms.
My goal here was to to make basic definations of only the most common terms a noob will come across. I didnt want to go into too great of detail, as it was just a way to get the basic understanding of things. I remembered back to my noob days (not that long ago actually, and still a noob in many ways) and remembered how helpfull something like this would have been.
I have split it up into two sections. Fuel injection terms, and tuning terms. Ones marked with a * mean I either need a good laymans term defination, or I need more info added and/or current info checked for correctness.
Please feel free to post up any good terms I may have left out so I can add them up, and inform me of any mistakes so I can correct them.

First is injection terms:

Lbs/Hr. (Pounds per Hour) a term. Most commonly used as a measurement of the flow rate of fuel injectors.

ALDL. (Assembly Line Diagnostic Link) a electrical connector. This is the plug, usally mounted on the underside of the dash thats a direct connection to the ecm/pcm and is used to read trouble codes, and datalog. This is what you will connect your laptop to.

CEL. (Check Engine Light) a light bulb. Will light up when the ecm/pcm finds there is a problem and sets a trouble code.

CTS. (Coolant Tempature Sensor) a sensor. A variable resistance sensor that is installed in the engine somewhere it can take a reading of the engine coolant temp. Usally on the intake close to the thermostat. Its used to let the ecm/pcm know the temp so it knows if the engine is hot or cold. Cold engines require more fuel. Also, ecm/pcm's are set to go into closed loop at a specific temp.

*CCP. (Charcoal Cannister Purge) A valve that can be controlled by the ecm/pcm. For emmisions

DIS. (Distributorless Ignition System) A ignition system that does not use a distributor. Instead it uses coil packs and ignition timing is triggered from the crankshaft by a trigger wheel.

ECM. (Engine Control Module) the computer. This is the computer that controlls your fuel injection. It controlls the engine only.

*EGR. (Exhaust Gas Recirculation) a valve. A egr valve controlled by a fuel injection computer opens at programed times or parameters to allow exhaust gas into the combustion chamber. Works the same as it did on vehicles with a carb, only its controlled by the ecm/pcm instead of coolant temp operated vaccume valves.

EPROM. (Eraseable Programmable Read-only Memory) a chip. This is the chip inside the ecm/pcm that holds the binary file or "tune". This is the part you remove, and read with a chip burner. Normally replaced by a EEPROM when tuning. A EPROM needs a special UV eraser, and are not a good choice for repeated eraseing and reprogramming. Not much of the tuning software and harware still support these chips, however most can still read them.
EEPROM. (Electronicly Eraseable Programmable Read Only Memory) a chip. This is the chip most tuners use. Its eraseable by simply putting it into a chiper burner and selecting the correct settings for the specific chip with the required sofware. Can be reused many many times.

ESC. (Electronic Spark Control) a module. The ESC module is connected to the ecm and a knock sensor. It takes readings from the knock sensor, determines if there is a engine knock or not. If it detects a knock via the knock sensor, it sends a signal to the ecm/pcm to tell it to retard the spark advance untill the knock goes away.
KS. (Knock Sensor) a sensor. The knock sensor is used by the ESC to pick up engine knock (or spark knock)

EST. (Electronic Spark Timing) a module. Basicly its the ignition module. Its connected to the pickup module in the distributor, and to the ecm/pcm.

FPR. (Fuel Pressure Regulator) Regulates the fuel pressure to a set ammount. Some are fixed (only one pressure all the time) some are adjustable (can be adjusted by the user) and some are vaccume refrenced. A vaccume refrenced has low pressure when there is vaccume applied (low/light load, or idle), and higher pressure when there is no vaccume applied (heavy load, wide open throttle).

IAC. (Idle Air Control) a stepper motor/valve. The IAC is a "valve" of sorts that is controlled by the ecm/pcm. It has a passage on the throttle body that bypasses the throttle blades and allows air through. By controlling how far open or closed the IAC valve is, the ecm/pcm controlls the idle speed of the engine.

*IAT. (Intake Air Temperature) a sensor. The IAT sensor reads the tempature of the air coming into the intake. It is usally mounted in the air filter housing or air intake tube. (need better info on its actual use/purpose)
　
*MAF. (Mass Air Flow) a sensor. The MAF sensor reads the ammount of air coming into a engine. This is a alternative to a MAP sensor, as the ecm/pcm can read the actual ammount of air coming into the engine. Some injection systems use both MAF and MAP sensors.

MAP. (Manifold Absolute Pressure) a sensor. The MAP sensor reads the ammount of vaccume inside the intake manifold. The ammount of vaccume is used by the ecm/pcm to calculate the ammount of load that is on a engine. A map reading of around 20 KPa would mean low load, a reading of 100 KPa would be high load (wide open throttle) This is used to calculate the ammount of fuel that is needed, and also how much spark advance to give.

*MAT. (Manifold Air Temperature) a sensor. The MAT sensor reads the tempature of the air inside the intake manifold. As the name states, its mounted in the intake manifold instead of the air intake. (need better info on its actual use/purpose)

MPFI. (Multi Port Fuel Injection) a term. A type of fuel injection system where there is a seperate fuel injector for each cylinder of the engine. Can also be called PFI, Port Fuel Injection.

NB, or NB02. (Narrow Band O2 sensor) a sensor. Oxygen sensor thats limited to only a narrow band of readings. Can only detect the normal 14.7 to 1 air fuel ratio. It can only tell if the air fuel ratio is rich or lean. It however can not sense exactly HOW rich or lean the mixture is.

O2. (oxygen) a element. Normally, in the fuel injection world, O2 is used as a short way of saying oxygen sensor. Usally seen as "O2 sensor"

PCM. (Powertrain Control Module) a computer. This is a fuel injection computer, basicly exactly the same as a ECM, however the PCM controlls not only the fuel injection, but also controlls the shifting of the transmission. Hence the term "powertrain controll", controlling both engine and transmission.

TBI. (Throttle Body Injection) a term. A fuel injection system where the fuel injectors are located directly above the throttle blades.

*TCC. (Torque Converter Clutch) Locks the torque converter so there is no slip, this helps with fuel mileage.

TPS. (Throttle Position Sensor) a sensor. Senses the ammount the throttle is opened. Since engine load can change without throttle change, the ecm/pcm needs the tps to know if the throttle is being opened or closed, and by how much, and how quickly. Things such as Acceleration Enrichment can be based off the TPS readings.

VSS. (Vehicle Speed Sensor) a sensor. Sends pulses (pulse type and number of pulses varies depending on vss and ecm/pcm) to the engine computer so it knows how fast you are going. The ecm/pcm uses this info to know if you are speeding up, slowing down, or driving steady. On some injection systems this part is not "required" and the the system will still function. Just some features will not work. If your using a PCM with transmission controlls, a VSS is required.

WB, or WB02. (WideBand O2 sensor) a sensor. A wideand 02 sensor differs from a regular or "narrow band" in that is can sense the exact air/fuel ratio. A wideband sensor can not only tell you that your running rich or lean, but can tell you exactly HOW rich or lean you are running. They are very usefull for tuning injection systems, and could even be used to tune a carb. However a wideband controller is required to use a WB02, and then also some way to display and record the data from the controller. Its normall output in a 0-5 volt signal. Most common injection systems are not set up to use a WB.

WOT. (Wide Open Throttle)

Next is tuning terms:

AE. (Acceleration Enrichment) This is basicly like a accelerator pump in a carb. It gives a extra shot of fuel when you hit the gas.

AFR. (Air Fuel Ratio) The ratio of how much air and how much fuel are mixed together. The most common you will see is 14.7, this is whats usally reguared as the desired ratio. The larger the number, the leaner (less fuel) the mixture is, and the smaller the number, the richer (more fuel) the mixture is.

BIN. (Binary) Binary is a form of computer code formed of zeros and ones. Its is how the info is stored on the EPROM. Most commonly seen as a bin file. This is what you use your tuning software to view. It displays the bin file in a format you can understand.

BARO. (Barometric Pressure)

BLM. (Block Learn Multiplier) This is the ecm/pcm auto correcting the air fuel ratio. The computers are allowed to self adjust to a specific ammount. That way they can keep the correct air fuel ratio as things such as weather, altitude, and the fuel itself change.

*INT. (Integrator) (need a good defination)

BPW. (Base Pulse Width) This is basicly how quickly the the injectors are opening and closing. A small (or short) BPW, the injectors are opening and then closing really quickly, letting less fuel through. A larger (or longer) BPW holds the injectors open longer to allow more fuel through.

Closed Loop. This is when the computer is activly taking readings from all the sensors and uses the data to make constant adjustments and changes to keep the air fuel ratio correct. It adjusts fuel to keep the desired ratio and adjust for things such as changes in elevation and weather.

Open Loop. This is when the computer is running the engine based off preset programming. The computer is not actively making fuel adjustments. Open loop is usally when the engine is cold. The engine (and 02 sensor) must get to a specific temp before closed loop is allowed. Things such as failed sensors or trouble codes can force open loop.

DE. (Deceleration Enleanment) When you let off the gas pedal the ecm/pcm will reduce the ammount of fuel going into the engine, as you dont need as much fuel as you do during normal driving. Keeps you from running rich during deceleration.

DFCO. (Deceleration Fuel Cut Off) Reduces the injector BPW to zero, basicly shutting off all fuel to the engine during hard decel. Makes compression braking (using the enging to slow you down instead of the brakes) stronger. Fuel it turned back on if you hit the gas again, or the engine speed drops to a pre programed rpm.

*DRP. (Distributor Reference Pulse)
　
KPa. (KiloPascals) a unit of measurement. This is how vaccume is displayed in most all fuel injection tuning. 100 KPa would equil to wide open throttle, no vaccume, 20KPa would equil high vaccume during deceleration.

PE. (Power Enrichment) richens the air fuel ratio during times of hard acceleration for more power. Simmilar in function to a power valve in a carb.

*VE. (Volumetric Efficiency)

Wow really nice work there JeepsandGuns! :thumbsup:

For those who don't know JeepsandGuns volenteered (appointed) :laugh: To take on this project. We have an abbreviation acronym thread and he wanted to make a EFI dictionary out of it. What a great start!
http://www.gearhead-efi.com/Fuel-Inj...-Abbreviations

So this is a team effort, look them over and see how accurate and I will start adding them to above thread. We will also have a webpage built for thses to link off the BCC Find section of the website!

Quote:

---

Originally Posted by JeepsAndGuns

Ok, in response to the documentation thread, here is my beta version of a noobs guide of common terms.
My goal here was to to make basic definations of only the most common terms a noob will come across. I didnt want to go into too great of detail, as it was just a way to get the basic understanding of things. I remembered back to my noob days (not that long ago actually, and still a noob in many ways) and remembered how helpfull something like this would have been.
I have split it up into two sections. Fuel injection terms, and tuning terms. Ones marked with a * mean I either need a good laymans term defination, or I need more info added and/or current info checked for correctness.
Please feel free to post up any good terms I may have left out so I can add them up, and inform me of any mistakes so I can correct them.

First is injection terms:

Lbs/Hr. (Pounds per Hour) a term. Most commonly used as a measurement of the flow rate of fuel injectors.

ALDL. (Assembly Line Diagnostic Link) a electrical connector. This is the plug, usally mounted on the underside of the dash thats a direct connection to the ecm/pcm and is used to read trouble codes, and datalog. This is what you will connect your laptop to.

CEL. (Check Engine Light) a light bulb. Will light up when the ecm/pcm finds there is a problem and sets a trouble code.

CTS. (Coolant Tempature Sensor) a sensor. A variable resistance sensor that is installed in the engine somewhere it can take a reading of the engine coolant temp. Usally on the intake close to the thermostat. Its used to let the ecm/pcm know the temp so it knows if the engine is hot or cold. Cold engines require more fuel. Also, ecm/pcm's are set to go into closed loop at a specific temp.

*CCP. (Charcoal Cannister Purge) A valve that can be controlled by the ecm/pcm. For emmisions

DIS. (Distributorless Ignition System) A ignition system that does not use a distributor. Instead it uses coil packs and ignition timing is triggered from the crankshaft by a trigger wheel.

ECM. (Engine Control Module) the computer. This is the computer that controlls your fuel injection. It controlls the engine only.

*EGR. (Exhaust Gas Recirculation) a valve. A egr valve controlled by a fuel injection computer opens at programed times or parameters to allow exhaust gas into the combustion chamber. Works the same as it did on vehicles with a carb, only its controlled by the ecm/pcm instead of coolant temp operated vaccume valves.

EPROM. (Eraseable Programmable Read-only Memory) a chip. This is the chip inside the ecm/pcm that holds the binary file or "tune". This is the part you remove, and read with a chip burner. Normally replaced by a EEPROM when tuning. A EPROM needs a special UV eraser, and are not a good choice for repeated eraseing and reprogramming. Not much of the tuning software and harware still support these chips, however most can still read them.
EEPROM. (Electronicly Eraseable Programmable Read Only Memory) a chip. This is the chip most tuners use. Its eraseable by simply putting it into a chiper burner and selecting the correct settings for the specific chip with the required sofware. Can be reused many many times.

ESC. (Electronic Spark Control) a module. The ESC module is connected to the ecm and a knock sensor. It takes readings from the knock sensor, determines if there is a engine knock or not. If it detects a knock via the knock sensor, it sends a signal to the ecm/pcm to tell it to retard the spark advance untill the knock goes away.
KS. (Knock Sensor) a sensor. The knock sensor is used by the ESC to pick up engine knock (or spark knock)

EST. (Electronic Spark Timing) a module. Basicly its the ignition module. Its connected to the pickup module in the distributor, and to the ecm/pcm.

FPR. (Fuel Pressure Regulator) Regulates the fuel pressure to a set ammount. Some are fixed (only one pressure all the time) some are adjustable (can be adjusted by the user) and some are vaccume refrenced. A vaccume refrenced has low pressure when there is vaccume applied (low/light load, or idle), and higher pressure when there is no vaccume applied (heavy load, wide open throttle).

IAC. (Idle Air Control) a stepper motor/valve. The IAC is a "valve" of sorts that is controlled by the ecm/pcm. It has a passage on the throttle body that bypasses the throttle blades and allows air through. By controlling how far open or closed the IAC valve is, the ecm/pcm controlls the idle speed of the engine.

*IAT. (Intake Air Temperature) a sensor. The IAT sensor reads the tempature of the air coming into the intake. It is usally mounted in the air filter housing or air intake tube. (need better info on its actual use/purpose)
　
*MAF. (Mass Air Flow) a sensor. The MAF sensor reads the ammount of air coming into a engine. This is a alternative to a MAP sensor, as the ecm/pcm can read the actual ammount of air coming into the engine. Some injection systems use both MAF and MAP sensors.

MAP. (Manifold Absolute Pressure) a sensor. The MAP sensor reads the ammount of vaccume inside the intake manifold. The ammount of vaccume is used by the ecm/pcm to calculate the ammount of load that is on a engine. A map reading of around 20 KPa would mean low load, a reading of 100 KPa would be high load (wide open throttle) This is used to calculate the ammount of fuel that is needed, and also how much spark advance to give.

*MAT. (Manifold Air Temperature) a sensor. The MAT sensor reads the tempature of the air inside the intake manifold. As the name states, its mounted in the intake manifold instead of the air intake. (need better info on its actual use/purpose)

MPFI. (Multi Port Fuel Injection) a term. A type of fuel injection system where there is a seperate fuel injector for each cylinder of the engine. Can also be called PFI, Port Fuel Injection.

NB, or NB02. (Narrow Band O2 sensor) a sensor. Oxygen sensor thats limited to only a narrow band of readings. Can only detect the normal 14.7 to 1 air fuel ratio. It can only tell if the air fuel ratio is rich or lean. It however can not sense exactly HOW rich or lean the mixture is.

O2. (oxygen) a element. Normally, in the fuel injection world, O2 is used as a short way of saying oxygen sensor. Usally seen as "O2 sensor"

PCM. (Powertrain Control Module) a computer. This is a fuel injection computer, basicly exactly the same as a ECM, however the PCM controlls not only the fuel injection, but also controlls the shifting of the transmission. Hence the term "powertrain controll", controlling both engine and transmission.

TBI. (Throttle Body Injection) a term. A fuel injection system where the fuel injectors are located directly above the throttle blades.

*TCC. (Torque Converter Clutch) Locks the torque converter so there is no slip, this helps with fuel mileage.

TPS. (Throttle Position Sensor) a sensor. Senses the ammount the throttle is opened. Since engine load can change without throttle change, the ecm/pcm needs the tps to know if the throttle is being opened or closed, and by how much, and how quickly. Things such as Acceleration Enrichment can be based off the TPS readings.

VSS. (Vehicle Speed Sensor) a sensor. Sends pulses (pulse type and number of pulses varies depending on vss and ecm/pcm) to the engine computer so it knows how fast you are going. The ecm/pcm uses this info to know if you are speeding up, slowing down, or driving steady. On some injection systems this part is not "required" and the the system will still function. Just some features will not work. If your using a PCM with transmission controlls, a VSS is required.

WB, or WB02. (WideBand O2 sensor) a sensor. A wideand 02 sensor differs from a regular or "narrow band" in that is can sense the exact air/fuel ratio. A wideband sensor can not only tell you that your running rich or lean, but can tell you exactly HOW rich or lean you are running. They are very usefull for tuning injection systems, and could even be used to tune a carb. However a wideband controller is required to use a WB02, and then also some way to display and record the data from the controller. Its normall output in a 0-5 volt signal. Most common injection systems are not set up to use a WB.

WOT. (Wide Open Throttle)

---

I think you did a great job! :thumbsup:

I helped where you had "*" and I added a couple and changed format from like EST.(Electronic Sprak Timing) a module to... EST = Electronic Spark Timing. then discription. Also did a spell check. So it's good to go if you want?

Lbs/Hr = Pounds Per Hour a term. Most commonly used as a measurement of the flow rate of fuel injectors.

ALDL = Assembly Line Diagnostic Link. This is the plug, usually mounted on the underside of the dash that’s a direct connection to the ECM/PCM and is used to read trouble codes, and datalog. This is what you will connect your laptop to.

CEL = Check Engine Light. A light bulb in dash board. Will light up when the ECM/PCM finds there is a problem and sets a trouble code.

CTS = Coolant Temperature Sensor. A variable resistance sensor that is installed in the engine somewhere it can take a reading of the engine coolant temp. Usually on the intake close to the thermostat. It’s used to let the ECM/PCM know the temp so it knows if the engine is hot or cold. Cold engines require more fuel. Also, ECM/PCM's are set to go into closed loop at a specific temp.

CCP = Charcoal Canister Purge a valve that can be controlled by the ECM/PCM. For emissions it is used to collect hydrocarbons from raw fuel and vent back to gas tank so no hydrocarbons are released into atmosphere.

DIS = Distributor-less Ignition System An ignition system that does not use a distributor. Instead it uses coil packs and ignition timing is triggered from the crankshaft by a trigger wheel.

ECM = Engine Control Module. This is the computer that controls your fuel injection. It controls the engine only.

EGR = Exhaust Gas Recirculation. Allows a small amount of exhaust gas to enter intake to lower combustion chamber temperatures reducing NOX emissions. The EGR valve controlled by a fuel injection computer is controlled by a solenoid to open at programmed times or parameters to allow exhaust gas into the combustion chamber. Works the same as it did on vehicles with a carb, only its controlled by the ECM/PCM instead of coolant temp operated vacuum valves.

EPROM = Erasable Programmable Read-only Memory. This is the chip inside the ECM/PCM that holds the binary file or "tune". This is the part you remove, and read with a chip burner. Normally replaced by an EEPROM when tuning. An EPROM needs a special UV eraser, and is not a good choice for repeated erasing and reprogramming. Not much of the tuning software and hardware still support these chips, however most can still read them.

EEPROM = Electronically Erasable Programmable Read Only Memory. This is the chip most tuners use. It’s erasable by simply putting it into a chip burner and selecting the correct settings for the specific chip with the required software. Can be reused many times.

ESC = Electronic Spark Control. The ESC module is connected to the ecm and a knock sensor. It takes readings from the knock sensor, determines if there is an engine knock or not. If it detects a knock via the knock sensor, it sends a signal to the ECM/PCM to tell it to retard the spark advance until the knock goes away.

KS = Knock Sensor. The knock sensor is used by the ESC to pick up engine knock (or spark knock)

EST = Electronic Spark Timing. Basically it’s the ignition module. It’s connected to the pickup module in the distributor, and to the ECM/PCM to control timing by engine computer.

FPR = Fuel Pressure Regulator regulates the fuel pressure to a set amount. Some are fixed (only one pressure all the time) some are adjustable (can be adjusted by the user) and some are vacuum referenced. A vacuum referenced has low pressure when there is vacuum applied (low/light load, or idle), and higher pressure when there is no vacuum applied (heavy load, wide open throttle).

IAC = Idle Air Control is a stepper motor/valve. The IAC is a "valve" of sorts that is controlled by the ECM/PCM. It has a passage on the throttle body that bypasses the throttle blades and allows air through. By controlling how far open or closed the IAC valve is the ECM/PCM controls the idle speed of the engine.

IAT = Intake Air Temperature. The IAT sensor reads the temperature of the air coming into the intake. It is usually mounted in the air filter housing or air intake tube. It is another measurement used to calculate air density in fuel equation.

MAF = Mass Air Flow. The MAF sensor reads the amount of air coming into an engine. This is an alternative to a MAP sensor, as the ECM/PCM can read the actual amount of air coming into the engine instead of density of air measured in load. Some injection systems use both MAF and MAP sensors. Some use MAP sensor for Barometric reading during key on startup.

MAP = Manifold Absolute Pressure. The MAP sensor reads the amount of vacuum inside the intake manifold. The amount of vacuum is used by the ECM/PCM to calculate the amount of load that is on an engine. A map reading of around 20 KPa would mean low load, a reading of 100 KPa would be high load (wide open throttle) This is used to calculate the amount of fuel that is needed, and also how much spark advance to give.

MAT = Manifold Air Temperature. The MAT sensor reads the temperature of the air inside the intake manifold. As the name states, it’s mounted in the intake manifold instead of the air intake. It is another measurement of air density to calculate with fuel mixture.

MPFI = Multi Port Fuel Injection. A type of fuel injection system where there is a separate fuel injector for each cylinder of the engine. Can also be called PFI, Port Fuel Injection.

NB or NB02 = Narrow Band O2 sensor. Oxygen sensor that’s limited to only a narrow band of readings. Can only detect the normal 14.7 to 1 air fuel ratio. It can only tell if the air fuel ratio is rich or lean. It however can not sense exactly HOW rich or lean the mixture is.

O2 = Oxygen an element. Normally, in the fuel injection world, O2 is used as a short way of saying oxygen sensor. Usually seen as "O2 sensor"

PCM = Powertrain Control Module. This is a fuel injection computer, basically exactly the same as an ECM, however the PCM controls not only the fuel injection, but also controls the shifting of the transmission. Hence the term "powertrain control", controlling both engine and transmission.

SES = Service Engine Soon. Same as CEL = a light bulb. Will light up when the ECM/PCM finds there is a problem and sets a trouble code.

TBI - Throttle Body Injection. A fuel injection system where the fuel injectors are located directly above the throttle blades.

TCC = Torque Converter Clutch. Locks the torque converter so there is no slip, this helps with fuel mileage.

TPS = Throttle Position Sensor. Measures the amount the throttle is opened. Since engine load can change without throttle change, the ECM/PCM needs the TPS to know if the throttle is being opened or closed, and by how much, and how quickly. Things such as Acceleration Enrichment can be based off the TPS readings.

VSS = Vehicle Speed Sensor. Sends pulses (pulse type and number of pulses varies depending on vss and ECM/PCM) to the engine computer so it knows how fast you are going. The ECM/PCM uses this info to know if you are speeding up, slowing down, or driving steady. On some injection systems this part is not "required" and the system will still function. Just some features will not work. If you’re using a PCM with transmission controls, a VSS is required.

WB or WB02 = WideBand O2 sensor. A wideand 02 sensor differs from a regular or "narrow band" in that is can sense the exact air/fuel ratio. A wideband sensor can not only tell you that your running rich or lean, but can tell you exactly HOW rich or lean you are running. They are very useful for tuning injection systems, and could even be used to tune a carb. However a wideband controller is required to use a WB02, and then also some way to display and record the data from the controller. Its normal output in a 0-5 volt signal. Most common injection systems are not set up to use a WB.

WOT = Wide Open Throttle Mashing the skinny pedal causes AE and PE to be enabled in fueling.

Quote:

---

Originally Posted by JeepsAndGuns

Next is tuning terms:

AE. (Acceleration Enrichment) This is basicly like a accelerator pump in a carb. It gives a extra shot of fuel when you hit the gas.

AFR. (Air Fuel Ratio) The ratio of how much air and how much fuel are mixed together. The most common you will see is 14.7, this is whats usally reguared as the desired ratio. The larger the number, the leaner (less fuel) the mixture is, and the smaller the number, the richer (more fuel) the mixture is.

BIN. (Binary) Binary is a form of computer code formed of zeros and ones. Its is how the info is stored on the EPROM. Most commonly seen as a bin file. This is what you use your tuning software to view. It displays the bin file in a format you can understand.

BARO. (Barometric Pressure)

BLM. (Block Learn Multiplier) This is the ecm/pcm auto correcting the air fuel ratio. The computers are allowed to self adjust to a specific ammount. That way they can keep the correct air fuel ratio as things such as weather, altitude, and the fuel itself change.

*INT. (Integrator) (need a good defination)

BPW. (Base Pulse Width) This is basicly how quickly the the injectors are opening and closing. A small (or short) BPW, the injectors are opening and then closing really quickly, letting less fuel through. A larger (or longer) BPW holds the injectors open longer to allow more fuel through.

Closed Loop. This is when the computer is activly taking readings from all the sensors and uses the data to make constant adjustments and changes to keep the air fuel ratio correct. It adjusts fuel to keep the desired ratio and adjust for things such as changes in elevation and weather.

Open Loop. This is when the computer is running the engine based off preset programming. The computer is not actively making fuel adjustments. Open loop is usally when the engine is cold. The engine (and 02 sensor) must get to a specific temp before closed loop is allowed. Things such as failed sensors or trouble codes can force open loop.

DE. (Deceleration Enleanment) When you let off the gas pedal the ecm/pcm will reduce the ammount of fuel going into the engine, as you dont need as much fuel as you do during normal driving. Keeps you from running rich during deceleration.

DFCO. (Deceleration Fuel Cut Off) Reduces the injector BPW to zero, basicly shutting off all fuel to the engine during hard decel. Makes compression braking (using the enging to slow you down instead of the brakes) stronger. Fuel it turned back on if you hit the gas again, or the engine speed drops to a pre programed rpm.

*DRP. (Distributor Reference Pulse)
　
KPa. (KiloPascals) a unit of measurement. This is how vaccume is displayed in most all fuel injection tuning. 100 KPa would equil to wide open throttle, no vaccume, 20KPa would equil high vaccume during deceleration.

PE. (Power Enrichment) richens the air fuel ratio during times of hard acceleration for more power. Simmilar in function to a power valve in a carb.

*VE. (Volumetric Efficiency)

---

Same thing, helped with some, added a few...

AE = Acceleration Enrichment. This is basically like an accelerator pump in a carb. It gives an extra shot of fuel when you hit the gas.

AFR = Air Fuel Ratio. The ratio of how much air and how much fuel are mixed together. The most common you will see is 14.7; this is what’s usually regarded as the desired ratio. The larger the number, the leaner (less fuel) the mixture is, and the smaller the number, the richer (more fuel) the mixture is.

Asynchronous Fuel Mode = This is a temporary mode in which the injectors are commanded on longer for transient conditions. The accelerator pump shot is an asynchronous mode function in which extra milliseconds are added to the injector pulse width when the throttle position sensor rapidly
changes state.

BIN = Binary. Most commonly referred to as the file on chip. Binary is a form of computer code formed of zeros and ones. Its is how the info is stored on the EPROM. Most commonly seen as a bin file. This is what you use your tuning software to view. It displays the bin file in a format you can understand.

BARO = Barometric Pressure. Reading taken at key on before start of atmospheric pressure.

BLM = Block Learn Multiplier. Block Learn Mode term is long term fuel trim. BLM value tracks the Integrator but has a delay. If the Integrator increases so does the BLM, but the BLM lags behind the Integrator. The higher the Integrator climbs above 128, the faster the BLM rises. BLM value affects the VE table by adding fuel above 128 and subtracting fuel below 128

BPW = Base Pulse Width the pulse width commanded to injectors under steady state engine conditions.

BPC = Base Pulse Constant is a term that is calculated from the volume of one cylinder, the flow rate of one injector,
and a constant that converts the units to match other terms.

BVC = Battery Voltage Correction is a term that corrects the fuel delivery rate for different battery voltages. The injector response is enhanced at higher voltages and is a bit sluggish by comparison at lower voltages. This term is a correction to offset the change in injector response due to battery voltage fluctuations.

INT = The short term fuel trim value is called the Integrator The value of the integrator varies above and below 128 with 128 being no correction. For example, if the Integrator is 135, the ECM is adding fuel because the 02 sensor is reading a lean mixture. If the Integrator is 110, the ECM is removing fuel because the 02 sensor is reading a rich mixture. Anytime the system is not in closed loop, the Integrator will immediately return to a value of 128 and stay there.

BPW = Base Pulse Width. This is basically how quickly the injector are opening and closing. A small (or short) BPW, the injectors are opening and then closing really quickly, letting less fuel through. A larger (or longer) BPW holds the injectors open longer to allow more fuel through.

Closed Loop = This is when the computer is actively taking readings from O2 sensor and uses the data to make constant adjustments and changes to keep the air fuel ratio correct. It adjusts fuel to keep the desired ratio and adjust for things such as changes in elevation and weather.

Open Loop = This is when the computer is running the engine based off preset programming. The computer is not actively making fuel adjustments from O2 sensor. Open loop is usually when the engine is cold. The engine (and 02 sensor) must get to a specific temp before closed loop is allowed. Things such as failed sensors or trouble codes can force open loop.

DE = Deceleration Enleanment. When you let off the gas pedal the ecm/pcm will reduce the amount of fuel going into the engine, as you don’t need as much fuel as you do during normal driving. Keeps you from running rich during deceleration.

DFCO = Deceleration Fuel Cut Off. Reduces the injector BPW to zero, basically shutting off all fuel to the engine during hard decel. Makes compression braking (using the engine to slow you down instead of the brakes) stronger. Fuel it turned back on if you hit the gas again, or the engine speed drops to a pre programmed rpm.

DRP = Distributor Reference Pulse.

KPa = KiloPascals. A unit of measurement. This is how vacuum is displayed in most all fuel injection tuning. 100 KPa would equal to wide open throttle, no vacuum, 20KPa would equal high vacuums during deceleration.

PE = Power Enrichment. Richens the air fuel ratio during times of hard acceleration for more power. Similar in function to a power valves in a carb.

VE = Volumetric Efficiency is a term that corrects fueling for different engine efficiencies. An engine is basically an air pump and the better the pump; the more power it can generate. Some engines are better pumps than others at a given RPM and MAP condition are, so this term allows the equation to be calibrated for different engines. It is used in open or closed loop. If perfect will produce 14.7 to 1 AFR without other sensor adjustments. It is the most important thing to get that right first because all other adjustments like AE, PE, DFCO and lean cruise are based off that.

Add a definition of idle.

I thought that idle was when the car was stopped, but I found out that your car can be idling when you are driving down the road.

Car idle occurs when the Throttle Position Sensor is at zero. But why does this occur when driving down the road and I have my foot on the accerator?

Thanks for all he good work.

Robert

Write it up! :thumbsup:

Idle = (put stuff here)

I will add them as they come along. This is a work in progress that can always be added to or further defined. Everyone is welcome!

Thanks for getting this going JeepsandGuns! You are now a hero! :happy:
http://www.gearhead-efi.com/gm-ecm-p...ictionary.html

Nice job on cleaning things up and correcting mistakes!

As with everyone reading this, please keep suggestions coming!! If there is something you remember not understanding when you were a noob, post it up so we can add it.


Another one, we touched on a bit in one thread, is "delta". There are several parameters that have "delta" in them, I think a good defination of what that means would be helpfull. Seems I remember it refers to a "changing" reading or something like that.

Yeah what ever happened with Delta? I thought it was a change within a certain set of boundries?

There's a list of more simple terms here if anyone cares to expand on any, we will add them.
http://www.gearhead-efi.com/Fuel-Inj...-Abbreviations

Yea, I am still a little grey on the defination. Thats why I would prefer someone who has a much better understanding of it write a good easy to understand defination.

Can we get this put into the list. The difference among Pulse Width, Base Pulse Width, and Base Pulse Constant.

Pulse Width = time injectors are open
Base Pulse Width = a measure of time used in the ECM/PCM to calculate how long to open the injectors. Adders such as AE, PE, and injector voltage bias get added to the Base Pulse Width to arrive at the Pulse Width to be sent to the Injectors. Sometimes used to describe Pulse Width.
Base Pulse Constant = A constant derived from a ratio of injector flow rate to cylinder volume.

Sorry, just something that drives me crazy, using a time related term to describe a constant we set in the ECM.

Of course we can! :thumbsup:

I found a couple more I have too so since we have a TTT I'll wait a day to update in case we get more input!

Thanks for this, a first class job that brought me here through a search. Well done!

Delta usually means a difference in pressures measured across a known orifice. Can be used to caluate flow, like EGR differential pressure sensor on a diesel. Can also be just a pressure difference .

Hi All. Newby question, but I have searched with no joy.
Wanting a definition for % A SPARK.
Think I'm in the right place, it's a TunerPro thing, and I'm after a definition.
From what I'm seeing, it's related to knock and timing advance, but % of what, and what's the 'A'?
Please delete in inappropriate, or wrong place. Or just put in a definition, and delete my waffle.
Thanks in advance
G

Someone has likely abbreviated another word to get A. Which xdf are you using?

Cheers 1P2M, XDF is Aussie Holden LS1 12225074
I'm playing with it on stock LS1 prior to dropping in stroker Eaton M122 combo.
I've attached log showing %ASPARK changing with knock, as does timing, on a stock bin with PE AFR modded and added 2 degrees spark.
Off topic, but I'm also wondering how I have 12:1 AFR, but O2 sensors still read stochiometric.
Main bit of interest is in 3rd gear WOT run at 37 to 47 seconds. ADX: LS1 DSKW v1.02

Love this thread! Along with the abbreviations thread referenced here, it'll save noobs like me hours of random reading and googling. (Don't ask how I know) :-) I particularly liked the VE entry. I'll try to add what I can.

Delta: A mathematical term referring to the difference between two readings such as ambient air pressure vs manifold absolute pressure, or the reading between the first and second O2 sensor. Or the difference between coolant temperature at two points in the flow circuit. The quantitative value of the difference is used in calculations the ECM or PCM uses to optimize the setting of another component or calculation.