EFI Dictionary

[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)

[EagleMark]

Wow really nice work there JeepsandGuns!

For those who don't know JeepsandGuns volenteered (appointed) 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!

[EagleMark]

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.

[historystamp]

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

[EagleMark]

Write it up!

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!
http://www.gearhead-efi.com/gm-ecm-p...ictionary.html

[JeepsAndGuns]

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.

[EagleMark]

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

[JeepsAndGuns]

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.

[barn]

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 .