GearHead-EFI members project EFI dictionary help needed!
Common fuel injection and tuning terms defined (beta version) here:
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)