EFI Acronyms and Abbreviations

EFI Acronyms and Abbreviations
#/Hr - Pounds per Hour or PPH
ABS - Anti-lock Braking System
A/C - Air Conditioning
AE - Acceleration Enrichment
AFPR - Adjustable Fuel Pressure Regulator
AFR - Air Fuel Ratio
ATDC - After Top Dead Center
ALDL - Assembly Line Diagnostic Link
BARO - Barometric Pressure
BBL - Barrel
BCM - Body Control Module
BDC - Bottom Dead Center
BIN - Binary
BLM - Block Learn Multiplier
BSFC - Brake Specific Fuel Consumption
BPC - Base Pulse Constant
BPW - Base Pulse Width
BTDC - Before Top Dead Center
CAT - Catalytic Converter
CCI - Computer Controlled Ignition
CCP - Charcoal Cannister Purge
CDI - Capacitive Discharge Ignition
CEL - Check Engine Light
CFI - Cross-Fire Injection
CLT - Closed Loop Term
CNP - Coil Near Plug
CTS - Coolant Temperature Sensor
DC - Duty Cycle
DE - Deceleration Enleanment
DFCO - Decel Fuel Cut Off
DIS - Distributorless Ignition System
DRP - Distributor Reference Pulse

EAC Valve An abbreviation for Electric air control valve. This is the GM version of a diverter air gulp valve, providing three functions in a single valve
•the normal diverter valve function, i.e., it diverts air on rapid increase in manifold vacuum;
•it relieves pressure by diverting air to the air cleaner when the air injection system pressure exceeds a certain set level;
•being solenoid-controlled, it allows air to be diverted under any desired operating mode.

ECM - Engine Control Module
ECT - Engine Coolant Temperature
EGR - Exhaust Gas Recirculation
EGT - Exhaust Gas Temperature
EPROM - Eraseable Programmable Read-only Memory
ESC - Electronic Spark Control, knock detection & retard
EST - Electronic Spark Timing, SA control
FAR - Fuel Air Ratio
FPR - Fuel Pressure Regulator
Ft/Lb - Foot Pounds
GPS - Grams Per Second
Gms/Sec - Grams per Second
HEI - High Energy Ignition
HP - Horse Power
IAC - Idle Air Control
IAT - Intake Air Temperature
INT - Integrator
Km - KiloMeters
Km/L - Kilometers per Litre
KPa - KiloPascals
KPH - Kilometers Per Hour
LM - Launch Mode
LSA - Lobe Separation Angle
MAF - Mass Air Flow
MAP - Manifold Absolute Pressure
MAT - Manifold Air Temperature
MPG - Miles Per Gallon
MPH - Miles Per Hour
MPFI - Multi Port Fuel Injection
NB - Narrow Band O2 sensor
O2 - Oxygen Sensor
P/S - Power Steering
PCM - Powertrain Control Module
PCV - Positive Crankcase Ventilation
PE - Power Enrichment
PPH - Pounds Per Hour
PROM - Programmable Read-only Memory
PSI - Pounds per Square Inch
PW - Pulse Width
PWM - Pulse Width Modulation
RPM - Revolutions Per Minute
SA - Spark Advance
SD - Speed Density
SES - Service Engine Soon
TACH - Tachometer
TBI - Throttle Body Injection
TCC - Torque Converter Clutch
TCM - Transmission Control Module
TDC - Top Dead Center
TF - Throttle Follower
TPS - Throttle Position Sensor
TSA - total spark advance
VAC - Vacuum
VAFPR - Vacuum Adjusted Fuel Pressure Regulator
VATS - Vehicle Anti-theft System
VE - Volumetric Efficiency
VRFPR - Vacuum Referenced Fuel Pressure Regulator
VSS - Vehicle Speed Sensor
WB - Wide Band O2 sensor
WOT - Wide Open Throttle

This is great for a newb like me. Thanks!

There's a lot more when you get into OBDII stuff. This is all I knew off top of my head...

Thank you sir. I was contemplating making my own list to keep all of these straight.

If anyone knows one not listed just post them up and I will edit the list.

Lots of this stuff that is coming together here in the forums I will turn into HTML pages for future reference and the search engines find HTML pages easier than php or cgi or any kind of forum type data base driven information.

We have all summer though... I spend more time inside doing these projects in winter! Gives me something to do while staying warm!

Thanks for this great information.. Love this Site!!!

This section is a great help. I have a question about a couple of term... most I can guess, but a GM definition would be more exact

ENDMODEL END MODEL PART NUMBER
SIDERAIL SIDE RAIL NUMBER
M1BTPTRN MODULE 1 BIT PATTERN NUMBER : This is the calibration code for one of the processors (Tside)
GP6EM2P1 MODULE 2 (GMP6-E) PART NUMBER BYTE : This is the calibration code for the other (Eside)

If we know the definition, the page could be updated to show...

Thanks,
-Tom

Are you sure the "Bit Pattern Number" is the calibration code? It seems like another name for Mask ID to me.

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Originally Posted by 1project2many

Are you sure the "Bit Pattern Number" is the calibration code? It seems like another name for Mask ID to me.

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Nope... not sure at all. Many sources of info differ. Could you explain calibration code?? In my understanding (a bit of a fog at best) we have:

Software : Code base for all similar PCMs
Calibration : Application specific parameters and tables
EEPROM : Car specific

I am just guessing that the overall combination of Cal and S/W might be designated "bit pattern" by GM (?)

EEPROM (I am working on at the moment) has a number of entries. Here is a copy of my TSide EEPROM content. It is not too bad to work through as only a few of the 512 locations are used.
Attachment 14210

The code is interesting in that it permits download of the various segments which are flagged for programming by a main loop. There are also blocks which set ram locations. These *might* be SPIed over to Eside for programming in the EEPROM there(?). These are blocks in the $40 range.

This is what I think I am looking at:
Attachment 14211

The "EEPROM programmed" bit is interesting in that it can be written only to zero. I believe this was used by the factory such that the vin would be set only once so they could keep track of all the numbers.

I plan to share my disassembly of the EEPROM program / read over the OBDII shortly. It would be good if you could correct my terminology just so I don't create a bunch of confusion.


I wonder if these details could be shared in the acronyms and abbreviations section? Other terms I am searching for... TFT

-Tom

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Could you explain calibration code??

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I don't have an official definition for "Calibration Code." I'm simply noting that it seems strange that one processor's "calibration code" would be called a "Bit Pattern Number" while the other processor would use "Part Number." Not only are GM's own terms different between the processors but the format varies from other OBDII calibration listing format.

Quote:

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In my understanding (a bit of a fog at best) we have:
Software : Code base for all similar PCMs
Calibration : Application specific parameters and tables
EEPROM : Car specific

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This seems logical to me. The software in most GM OBDI vehicles is identified by a "Mask ID" which correlates to a bit pattern for the calibration data, the application specific parameters. The mask ID is not unique to specific software and in some cases the amateur tuning community has designated additional identifiers where two different programs use the same Mask ID. Based on this I was wondering if the "Bit Pattern" in the 8051 was roughly equivalent to the "Mask ID."

Hmmm... In TIS the LT1 powered vehicle calibrations appear to be listed a little differently than other OBDII flashable calibrations. For the LT1 vehicles the calibrations have a single part number. Under each part number there are two Calibration ID#'s and no Calibration Verification Numbers. An example is Cal Part No. 16230431 which includes Cal ID#'s 16230337 and 16230336. There is a bulletin available, 57-65-17A, which lists a number of "old calibration" and "new calibration" numbers. I cannot tell if the numbers refer to the "Part Number" or one of the two "Calibration ID's." If you are interested in viewing the bulletin and some GM calibration numbers you can use TIS with VIN 1g1bl52p2tr144830. Maybe having the ability to match numbers found in the 8051 with numbers in TIS or the service bulletin will be helpful?

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Here is a copy of my TSide EEPROM content.

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Interesting. The VIN stored in the EEPROM returns part number 16236231 calibration ID's 16236217 and 16246055. Unfortunately I have little additional information to offer.

Can anyone give a good description of "prime pulse". I have run across the term "second prime pulse" and would like to know about it.

Guessing this could be an initial injector squirt of fuel to get things going (?)

-Tom

It will be priming the engine with fuel.

1st prime pulse
2nd prime pulse

In Lt1s it dumps predefined pulse width of injector opening on the first and second low res pulses the pcm sense.
It is in batch mode firing. After that the fuel is calculated based on calibration`s crank VE table and is in sequencial mode of firing.

Quote:

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Originally Posted by kur4o

It will be priming the engine with fuel.

1st prime pulse
2nd prime pulse

In Lt1s it dumps predefined pulse width of injector opening on the first and second low res pulses the pcm sense.
It is in batch mode firing. After that the fuel is calculated based on calibration`s crank VE table and is in sequencial mode of firing.

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Thanks, that helps. About to post some analysis of the timer chip... switching threads.

-Tom

i have an 88 vet working off of an 89 bin and i keep seeing lv8 and there are no definitions for it. anyone know what this is::::