Basic Ecu Tuning [PDF]

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Basic’s "Chipping" an ECU means replacing the program running the ECU. Chipping is just slang. What we actually do is program (or "burn") a new bin file to the ROM to replace the program currently running the ECU. In order to chip an ECU, you will need the following:



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Soldering Iron - to solder chips in to the ECU Desoldering Tool - to remove chips/solder from an ECU. A Desoldering Iron, Desoldering Braid, or a Desoldering Station will also work. Read the Desoldering Tips. If you are uncomfortable doing this, or dont have access to the tools, some of the PGMFI members will sell you a ZIFSocketed ECU Rom Editor - to create new bin file to burn to the Chip Rom Burner - to a chip to replace the stock program ROM Library - To get some ready made bins Chips For ECUs - to burn the new Bin file to - the ATMEL AT29C256 seems to be the chip to get Parts For ECUs- is a fairly comprehensive list of the parts needed for ECUs.



Sounds pretty easy eh? Dave B. wrote a great Introduction To ECUChipping article that is an excellent place to start learning about chipping ECUs NOTE: OBD0 MPFI ECUs do not always have a ROM for you to replace. Don't despair, Chipping An8889 ECU is possible, too.



Introduction to ECU Chipping by David Blundell Please feel free to link to this article, but "mirroring" is highly discouraged, as you will not automatically receive updates.



How it all works With the move from carburetors to fuel injection, computers have assumed an important role in the proper functioning of an engine. The level of precise control possible with a ECU (Engine Control Unit computer for running an engine) can not only allow for greatly improved fuel economy, but can also allow for fine tuning of an engine to a degree that is arguably impossible with the best carburetors. Many ECUs, including those made by Honda, do data interpolation, allowing them to intelligently compensate for engine conditions that fall "between" known states, allowing for an almost continuously variable response to varying engine conditions. Additionally, the ECU can make small corrections to fuel/timing based on the state of various engine sensors. It is probably fairly fair to say that from the factory, most manufacturers tune for fuel economy, emissions and poor quality gasoline as opposed to power and race gas. Honda is no exception to these rules about tuning. Basis for this can be seen very clearly by comparing European/US fuel and timing maps to Japanese timing maps for the same engine. Japanese have gasoline that is on average a minimum of about 10 octane points greater than gas sold in the US. Comparing JDM and USDM/EDM timing curves generally show the JDM maps having several degrees more spark advance, reflecting the manufacturer's expectation of better quality gasoline. You have to wonder about how much 205 HP out a 1.8L (ITR) can be improved on within the constraints of pump gas. It wouldn't surprise anyone if another 5-10 peak HP and a considerable amount of lowmidrange torque could be squeezed out of an ITR by HOURS on a dyno, and some changes to the ECU



program. This goes to show that even on Honda's "performance" motors, very conservative assumptions are made about the quality of gasoline used. If you are willing to run high octane gasoline consistently, significant performance improvements can usually be found by tuning the car for the better quality gas. This does bring us to an important point. Tuning is best something done on a dyno that can simulate loads (such as a Dynapack or Mustang dyno). Dynojets are only useful for tuning a much narrow range of operating conditions, namely acceleration at wide open throttle through the rev reange. When a Dyno is not available, something to give an objective measure of how the car is responding is a good second choice. Wideband O2 meters and EGT probes can give you some idea of what is going on. Widebands generally provide more direct information about Air Fuel Ratio, but they are generally ineffective for timing adjustment. EGT probes tell how how the exhaust leaving a motor is, which can be used to infer a lot of information. If Air Fuel Ratio is left relatively constant, most changes in EGTs can be attributed to timing adjustment. Air Fuel Ratios will cause changes in EGTs so make sure you have your AFRs nailed reasonably close to your target before trying to use an EGT to tune your timing. This article in intended as a brief introduction, so enough of that. Don't despair if you don't have access to a dyno, however. Accelerometers (like the G-Spot) measure acceleration forces with fairly good (