Why Do We Tune Honda / Acura vehicles with OEM ECUs?
- What vehicles and ECUs are covered
- What hardware is needed to tune these vehicles
- What software can we use with this hardware to tune these vehicles with
What vehicles and ECUs are covered
First, what vehicles are we able to tune with factory ECUs? The shear amount of options here is what leads us to these tuning solutions
Honda Civic 88-91 DPFI (Dual Point Fuel Injection)
- While the ECUs that come factory in these vehicles are not chippable/tunable...their stock wiring is close enough that we can use other ECUs with very easy wiring modifications. First, you will need to convert to MPFI (multi point fuel injection) and then decide if you want to tune with OBD0 or OBD1 ECUs. Once converted to MPFI, these vehicle can easily run an OBD1 ECU with an OBD0 to OBD1 ECU Conversion Harness making it even more versatile.
Honda Civic 88-91 MPFI (Multi Point Fuel Injection)
- The 88-89 MPFI ECUs (PM6-A080, is one example of the ECU code from these computers) for all intensive purposes are NOT chippable ECUs...they can however be equipped with a daughterboard that allows them to use a chip
- The 90-91 MPFI ECUs (PM6-A09, PS9-A09….examples) are equipped from the factory with a soldered in Eprom chip, that can be desoldered and removed and replaced with an eprom socket. From here these ECUs can be easily tuned with the proper equipment. Because these are already MPFI from the factory, these vehicle can easily run an OBD1 ECU with an OBD0 to OBD1 ECU Conversion Harness making it even more versatile.
Acura Integra (JDM XSi) 88-91
- This JDM Integra is equipped with the PR3 or PW0 ECU. You generally wont find this ECU in a stock US vehicle, but usually comes with the 1st Gen B16 swap bought from JDM Importers and swapped into the 88-91 Civics and Integra Chassis. These are equipped from the factory with a soldered in Eprom chip, that can be desoldered and removed and replaced with an eprom socket. From here these ECUs can be easily tuned with the proper equipment.
Acura Integra 90-91 (LS GS)
- The 90-91 MPFI ECUs (PR4-A01, PR4-A02, PR4-A10….examples) are equipped from the factory with a soldered in Eprom chip, that can be desoldered and removed and replaced with an eprom socket. From here these ECUs can be easily tuned with the proper equipment. Generally you want to stay away from the Auto ECUs but they should generally work the same in a manual chassis…I wouldn’t advise trying to use a chipped ECU in an Auto Application for tuning purposes. None of the editors out there were ever designed to be used with Auto Transmissions. Because these are already MPFI from the factory, these vehicle can easily run an OBD1 ECU with an OBD0 to OBD1 ECU Conversion Harness making it even more versatile.
Honda Civic 92-95 (DX, LX, CX, Si, Del Sol)
- Basically EVERY ECU from this generation of Civic is usable and chippable (do not use P07 ECUs). While there was no factory eprom in most of the ECUs found in these cars, Honda did provision a chip spot on the circuit board that can be used by soldering in the correct components. They also used a consistant circuit board design among the Non VTEC and VTEC Setups, which allows us to easily add the proper circuitry and a chip for controlling VTEC operation in a factory equipped ECU that wasn’t a VTEC model. These ECUs are extremely versatile and the most used. Look mostly for the following ECU codes in the US autos: P05, P06, P28, P09. These ECUs are easily converted to controll VTEC as well.
Acura Integra 92-93 (GSR)
- This was an odd model integra with a stroked B16 to 1.7L dubbed the 1.7 liter GSR motor. This is an OBD1 ECU equipped auto with only the code P61 on the side of the ECU. Basically, the P61 is a P28 ECU with a knock sensor board…this is the ONLY difference between the two ECUs. This ECU is chippable just like all OBD1 ECUs.
Acura Integra 92-93 (LS GS)
- This was the OBD1 B18A motor equipped Integra. The OBD1 ECU carries the same base code labeling as its OBD0 predecessor, this is an OBD1 PR4 ECU which is very similar to the P05 and P06 ECUs from the Civic. The only notable feature of some of these ECUs is that the Automatic version PR4 has EGR solenoid circuitry equipped on the ECU from the factory. Many people are now using this Pulse Width Solenoid modulation circuitry for boost control with editors like S300 and eCtune. This ECU is chippable just like all OBD1 ECUs and able to be converted to control VTEC function as well as IAB control.
Acura Integra 94-95 (GSR)
- This is the B18C1 motor equipped, high output VTEC 1.8L motor. This model comes with an OBD1 P72 ECU that has control for the GSR intake manifold secondary butterfly valves (IABs) and also has a knock sensor board equipped. This is probably one of the rarer and more expensive ECUs to source in the US. This ECU is chippable just like all OBD1 ECUs.
Acura Integra 94-95 (LS)
- This model is equipped with the OBD1 P75 ECU for the 1.8L non VTEC motor (B18b). This ECU is chippable just like all OBD1 ECUs and able to be converted to control VTEC function as well as IAB control.
Honda Civic 96-98 --- Acura Integra 96-99 --- Honda Accord 96-97
- This is an OBD2 equipped automobile, however, with a simple ECU Plug conversion harness (OBD2a to OBD1)…you can now run any OBD1 ECU in this vehicle. Always one item to pay attention to is that some OBD2 models come equipped with a 3 Wire IACV (Idle air control valve) and the OBD1 ECU can only control a 2 Wire IACV. Thus, you need to fit a 2 Wire IACV to the Vehicle and possibly play with a little wiring. Generally this is only a concern on vehicles that were equipped with an Auto Transmission but it is a point to note for OBD2 vehicles.
Honda Prelude 96-01
- This is an OBD2 equipped automobile, however, with a simple ECU Plug conversion harness (OBD2a to OBD1)…you can now run any OBD1 ECU in this vehicle. Always one item to pay attention to is that some OBD2 models come equipped with a 3 Wire IACV (Idle air control valve) and the OBD1 ECU can only control a 2 Wire IACV. Thus, you need to fit a 2 Wire IACV to the Vehicle and possibly play with a little wiring. Generally this is only a concern on vehicles that were equipped with an Auto Transmission but it is a point to note for OBD2 vehicles. Another point to note on these vehicles is that IAB control is reversed from OBD1, if you wish to retain IAB control, some further wiring and research may be necessary.
Honda Civic 99-00 --- Acura Integra 00-01 --- Honda Accord 98-02
- Again, this is an OBD2 equipped automobile, however, with a simple ECU Plug conversion harness (OBD2b to OBD1)…you can now run any OBD1 ECU in this vehicle. Always one item to pay attention to is that some OBD2 models come equipped with a 3 Wire IACV (Idle air control valve) and the OBD1 ECU can only control a 2 Wire IACV. Thus, you need to fit a 2 Wire IACV to the Vehicle and possibly play with a little wiring. Generally this is only a concern on vehicles that were equipped with an Auto Transmission but it is a point to note for OBD2 vehicles.
As you can see, this entire list is most of the Honda and Acura automobiles that are on the road today being tuned in a variety of ways. Because you can basically cover the entire gamut of makes and models with one ECU…this makes your ability as an engine management tuner much easier.
What hardware is needed to tune these vehicles
You only need three to four main pieces of hardware to tune these vehicles and ECUs. Of course you need a properly operating vehicle and a chipped ECU for your specific application to start.
- Here the ECU uses serial communication to output data. We intercept this data and convert it into a signal that a laptop computer can decipher. You can use either a Serial or USB datalogging (convertor) to accomplish this. A couple of this to note. The program running in the ECU must have datalogging added to it and you need to be running a datalogging program or an editor with built in datalogging that can read that particular datalogging protocol to actual read live data from the ECU. Just hooking up a datalogging cable between the ECU and a laptop computer and looking for data wont work. The ECU has to know what to send to the laptop and the laptop needs to know how to decipher the info it receives from the ECU.
Real Time Live Emulator
- An emulator is connected to the ECU in the same spot as the chip would go (in the same direction) and basically pretends it is a chip to the ECU. The other side of the emulator is connected to the laptop computer which can upload a program or changes to a program while the car is running. The emulator is an electronic buffer between the ECU and laptop so as not to upset the operation of the ECU while the car is running. This allows us to slip in changes on the fly and see how are changes make the car run differently as we make them. This isn’t a 100% critical component to tuning, but it sure makes the process faster. You can however continue to burn chips with changes made to them…but each time you do this you must shut down the car, remove the chip in the ECU and replace it with the newly burned chip and then repeat the process over and over which can become very tedious.
Wideband Oxygen Sensor
- Proper Air/Fuel ratio is one of, if not the most important part of tuning. To properly read your Air/Fuel ratio you need a WIDEband O2 sensor controller (kit) to do this. There are many of these affordable and readily available units on the market today.
This is the piece that controls all operations of the ECU tuning. You ALSO need to decide which software you are going to run on this laptop…I consider this pair of software and hardware one piece.
Point to note is that developments are in the works and have been made with some hardware and software out there that allow you to make real time changes (emulator) and datalog with one simple piece of hardware that either attached to the ECU or is installed inside of the ECU casing. Hondata came out first with the S300 unit which fits inside of the ECU case and is connected via one single USB cable to a laptop computer. Neptune RTP was released shortly after with the same premise as the S300 with different software and slightly different features. Shortly, there will be a piece of hardware released for the DIY genre of ECU Editors that accomplishes the same thing as S300 and Neptune RTP but on an open source level.
What software can we use with this hardware to tune these vehicles with?
This can be classified into two categories, Do It Yourself and Commercial Software.
Do It Yourself Software - OBD0
- This editor uses code created by some of the founders of the PGMFI.org website and allows for applications of mild boost setups, rev limits, launch control, boost cut and a few other minor features. I recommend it for low boost street setups that make less than 300 hp and need 450cc injectors or less for fueling. I also only recommend it for non VTEC setups as the limited VTEC control it does offers is basic at best. This program is FREE.
- This editor and most of the code for the PR3 and PW0 ECUs was created mostly by one guy, Ben Ogle and the name stands for Ben Ogle’s Rom Editor. There is good solid code for the OBD0 VTEC platform and he is continuing to work on bugs and add new features all the time with proper feedback from users. It also supports other code base like the NG60 Rom that TurboEdit uses. This program is FREE.
Do It Yourself Software - OBD1
- Currently still being designed and tested, my belief is that this will be the most comprehensive editor on the market. Where other software lack features from one to the next, this has every feature of every software currently on the market and more. There are just too many to list. Pricing for commercial dealers and DIYers has not been released as of yet.
Crome Engine Management (http://www.tunewithcrome.com)
- This has been on the market for a while now and been the major player sticking around to date for OBD1 ECU tunability. Many of the features were create by users and released publicly for free as this is a scriptable ROM editor which means that you have the ability to create your own features if you have some coding abilities. All of the available features you could possibly need to adjust as a user are in the FREE version available for download. The only feature you gain by purchasing a PRO license is the ability to datalog within the program itself instead of using an external datalogger. This is a very handy feature and well worth the PRO price tag.
- Uberdata was a pioneer in the Honda ECU Editor market, a couple of years back the designer abandon his project and left its pieces. Good enough for most setups and a great free tool to learn and tinker with, many people use it to this day and it is supported by its loyal users. From a commercial stand point, its probably not a great option.
Commercial Software - OBD1
Hondata - (http://www.hondata.com)
- This is Hondata’s “chip tuning” module that has been around for a while. See Hondata’s website for more info (http://www.hondata.com)
- This is Hondata’s newest All-in-one board that has full ability to datalog and emulate on the same piece of hardware. Other notable features are PWM Boost Control from the ECU and On-Board datalogging memory for when a laptop cannot be attached.
- RTP Board
- This is HR Tuning’s All-in-one tuning board that has on board datalogging and real time emulation. The software is complete and well tested with years of top notch tuners developing it. One main feature of Neptune is that it can be used on a Mac latop as there is software. This is the only OBD1 Editor that has native Mac support.
- Chip Tuning Dealers
- Dealers that are able to chip tune are hand picked and selected by HR Tuning. Customers pay a license fee to be tuned on Neptune to the dealer.
- Been around forever, but rarely seen…this item is still a player I guess so it should be mentioned as it does work. There is just no datalogging with this software so I don’t consider it a complete tuning software or nearly worth the price.
See our other write-ups for more specific applications. I hope this article helps shed some light on why Honda vehicles are so easily tuned and the variety and that the possibilities of different parts combinations and tuning variety are endless.
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