Sensors
Honda Distributor Operation and Function
A comprehensive overview of Honda distributor operation, function, and role in the ignition system across OBD0, OBD1, an...
OBD1 Honda P28 ECU Reference Guide
A hardware and software reference guide for the USDM and EDM OBD1 P28 SOHC VTEC ECU, the industry standard for custom Ho...
Electrical Load Detector (ELD) Operation
The Electrical Load Detector (ELD) monitors vehicle electrical consumption to allow the ECU to proactively adjust idle p...
Engine Coolant Temperature (ECT) Sensor Reference
Technical overview of the Engine Coolant Temperature (ECT) sensor in Honda engines, including its role in fueling, ignit...
Intake Air Temperature (IAT) Sensor Reference
Technical overview of the Intake Air Temperature (IAT) sensor and its critical role in air density calculations and fuel...
Cylinder Position (CYP) Sensor Operation and Diagnostics
An overview of the Cylinder Position (CYP) sensor function, location, and its critical role in sequential ignition timin...
Atmospheric Pressure (PA) Sensor Technical Reference
Technical guide to the Atmospheric Pressure (PA) sensor in Honda ECUs, explaining its role in altitude compensation and...
Real Time Programming (RTP) Hardware
An overview of Real Time Programming (RTP) hardware solutions for Honda ECU tuning, enabling on-the-fly calibration chan...
UberData Tuning Software Overview
Historical overview of the UberData tuning software, one of the original free platforms for Honda OBD1 ECU remapping.
Honda ECU Sensors
A comprehensive overview of the primary and optional sensors utilized by Honda ECUs to manage fuel injection, ignition t...
Vehicle Speed Sensor (VSS) Technical Reference
Technical overview of the Honda Vehicle Speed Sensor (VSS), including signal characteristics, diagnostic procedures, and...
Electronic Component Sourcing for ECU Repair
Guidance on sourcing electronic components for ECU modification and repair, highlighting the shift away from retail hobb...
P70 OBD1 ECU Technical Reference
Technical reference for the P70 OBD1 ECU, commonly found in 1992-1995 Honda Domani vehicles equipped with the SOHC VTEC...
1991 PM7 ECU Technical Reference
Technical reference for the 1991 PM7 ECU, including idle target configuration and sensor management.
Digital Multimeter Fundamentals
A comprehensive guide to using a digital multimeter for measuring voltage, current, and resistance in automotive electri...
Electronic Air Control Valve (EACV) Operation
A detailed technical overview of the Electronic Air Control Valve (EACV), also known as the Idle Air Control Valve (IACV...
Engine Revolutions Per Minute (RPM) Signal
An overview of how the Engine Control Unit (ECU) calculates Revolutions Per Minute (RPM) using the Crankshaft Position (...
Intake Air Bypass (IAB) System
An overview of the Intake Air Bypass (IAB) system, which optimizes engine performance by switching between long and shor...
Intake Air Temperature (IAT) Sensor Specifications
Technical specifications and resistance-to-voltage characteristics for the Honda Intake Air Temperature (IAT) sensor.
Modern Knock Detection Strategies for Honda ECUs
An overview of modern alternatives to the factory Honda knock detection system, focusing on advanced signal processing a...
OBD1 Civic and Integra ECU Reference
Technical reference for OBD1 Honda Civic and Acura Integra ECU pinouts, sensor configurations, and diagnostic specificat...
RS232 Serial Communication Protocol
An overview of RS232 serial communication protocols, including voltage levels and standard PC interface compatibility.
Technical Documentation and Resource Guidelines
A professional reminder to consult official technical documentation and service manuals before performing complex Honda...
Transistor-Transistor Logic (TTL) Reference
Transistor-Transistor Logic (TTL) utilizes 0/+5V signaling levels for native serial communication between microcontrolle...
Chipping OBD1 Small-Case ECUs
Step-by-step instructions for socketing and chipping small-case Honda OBD1 ECUs, commonly found in JDM and some European...
Guide to Honda ECU Hardware Modifications
A comprehensive index of hardware modifications for Honda OBD0 and OBD1 ECUs, including VTEC conversions, IAB additions,...
Oki 66K Assembly Language Routines for Honda ECUs
A technical reference collection of Oki 66K assembly language routines and code snippets for modifying Honda OBD1 and OB...
Adding IAB Control to an OBD1 P28 ECU
Hardware modification guide to add Intake Air Bypass (IAB) secondary runner controls to an OBD1 Honda P28 Civic ECU.
Automatic to Manual Transmission ECU Conversion
Convert an automatic transmission ECU to manual transmission operation by removing specific resistors and adding a jumpe...
Disabling VTEC VSS Check on P72 ECU
Technical guide for disabling the 25mph Vehicle Speed Sensor (VSS) requirement for VTEC engagement on the OBD1 P72 ECU.
DIY Technical Philosophy
An overview of the DIY philosophy and technical approach for Honda engine management and sensor diagnostics.
Dual Point Fuel Injection (DPFI) System Overview
An overview of the Dual Point Fuel Injection (DPFI) system used in early Honda engines, detailing its operational charac...
Dual-Point Fuel Injection (DPFI) Overview
An overview of the Dual-Point Fuel Injection (DPFI) system, its operational limitations, and its role in early Honda eng...
Engine Tuning Concepts and Reference
A comprehensive reference guide to essential engine tuning concepts, including sensor data, air-fuel ratios, and diagnos...
Factory Service Manuals (Helms)
A guide to utilizing factory service manuals, commonly known as Helms manuals, for accurate Honda wiring diagrams, mecha...
Honda and Acura Factory Service Manuals
Official source for Honda and Acura factory service manuals covering EF, EG, DA, and DC chassis platforms.
Honda ECU Rev Limiter Operation
A rev limiter prevents engine over-revving by restricting maximum RPM. Most Honda ECUs utilize a fuel-cut strategy to ac...
Honda PR3 ECU Reference Guide
Hardware and software reference guide for the OBD0 and OBD1 PR3 DOHC VTEC ECU used in B16A-equipped Integra and Civic mo...
Keihin Indiana Precision Technology (IPT)
Overview of Keihin Indiana Precision Technology (IPT) and their role in the manufacturing and design of Honda Engine Con...
MAX233 TTL to RS232 Level Translator
The Maxim MAX233 integrated circuit provides TTL to RS232 level translation for serial communication without requiring e...
NEC uPD7004C Analog-to-Digital Converter
Technical specifications, pinout mapping, and channel routing for the NEC uPD7004C Analog-to-Digital Converter (ADC) chi...
OBD0 Fuel Calculation Formula
Technical reference for the OBD0 fuel calculation formula, including pulsewidth derivation and variable definitions.
OBD0 Honda PW0 ECU Reference Guide
A comprehensive hardware and software reference guide for the JDM and European OBD0 PW0 DOHC VTEC ECU, including ROM add...
OBD1 8-Bit Ignition Advance Calculation
Technical reference for calculating ignition timing advance values in 8-bit OBD1 Honda ECUs using the standard conversio...
OBD1 ECU Address Latch Reference
Technical explanation of address latches (e.g., 74HC373) used in Honda OBD1 ECUs to interface the MCU with external EPRO...
OBD1 Honda P72 ECU Reference Guide
A comprehensive hardware and software reference guide for the OBD1 P72 Integra GS-R DOHC VTEC ECU, including RAM and ROM...
P28-G03 ECU Technical Reference
Technical reference for the P28-G03 ECU, an OBDII unit found in 1996+ European Honda del Sol SOHC VTEC models.
P29 OBD1 ECU Technical Reference
Technical reference for the P29 OBD1 ECU, commonly found in JDM Honda Domani and Civic 25th Anniversary models equipped...
P51 ECU Technical Reference
Technical reference for the P51 OBD1 ECU found in the 1992-1993 JDM Honda Ascot Innova 2.3L Si-Z (H23A).
P91 OBD1 ECU Reference
Technical reference for the P91 OBD1 ECU found in 1992-1995 JDM Honda Civic Coupe models equipped with the 1.6L SOHC VTE...
PG7 ECU Identification and Variants
Technical reference for the PG7 ECU, distinguishing between the 1986–1987 vacuum advance and 1988–1989 electronic advanc...
PK3 ECU Technical Reference
Technical overview of the PK3 ECU used in 1990-1991 Honda Prelude B20A DOHC non-VTEC engines.
PS9 ECU Technical Overview
Technical overview of the PS9 ECU, a 1990-1991 USDM Civic EX unit featuring integrated automatic transmission control ci...
PW1 ECU Technical Reference
Technical reference for the PW1 ECU, commonly found in D-series Honda applications such as the 1993 Concerto.
Real-Time Programmable ECU Boards
A reference guide to real-time programmable hardware boards compatible with Honda ECU systems, including the Easy-RTP v1...
Single Overhead Cam (SOHC) Engine Architecture
An overview of Single Overhead Cam (SOHC) engine architecture, detailing the function of the camshaft in controlling int...
Spark Advance Fundamentals
Spark Advance defines the angular rotation in degrees between the ignition event and the piston reaching Top Dead Center...
Top Dead Center (TDC) Sensor Technical Reference
Technical overview of the Honda Top Dead Center (TDC) sensor, including its location within the distributor and signal o...
VTEC Low Cam Profile
An overview of the VTEC Low Cam profile, which is optimized for fuel efficiency and idle stability during low-RPM operat...
Wabi-Sabi Aesthetic Philosophy
An overview of the wabi-sabi aesthetic philosophy and its influence on Japanese design principles and traditional beauty...