How to reprogram a car's engine control module is part of a guide to car tuning.
The first part of this article is about basics.Before attempting to code, you need to be familiar with this information.
The car's electronics are like its brain.You have to keep your car in top shape for it to deliver its best performance.
This is the only way to make sure you get the best in both driving and handling.Modern day cars don't have manual controls.Computerized controls are used to guide and ensure engine performance.
The data pertaining to a physical intervention is recorded in the memory banks of your car's computer.
The optimum control conditions in which the engine should function are worked out by the computer.
In order to ensure an ideal drive, the engine needs to take a course of action that is shuffled through the data in the form of readings.The engine's control unit tells you how to do it.stored data is used to make accurate diagnosis on engine control.
Even though you have made modifications to your car, theECU still gets an input of the old data which is stored in it's memory.The old data is no longer credible as it relates to conditions before the modification.
The input data should relate to the situation after the modification of components and parts.The old data has to be erased from the memory and the new data should be mapped into theECU memory.This is the reason why your car's electronics need to be reset after a modification.
The data in your car's memory should be erased when you carry out the modification.The conditions that have come into existence should be fed in fresh data.The new data reflects the true conditions after the modification.
You should know how to reset theECU of your car.You have to let your car adapt to the new situation.Allow your computer to relearn.
The first thing to be done is to purge the old data.It is possible to adapt itself to new parts and perform post modification.The negative battery cable connection is needed to reset theECU.It's best to leave it in this disconnected state for as long as you can.Leaving it disconnected overnight is enough.
You have to connect back the cable after you disconnected it.Keep the car running until it warms up.It wouldn't take more than 10 minutes in the summer.Once you have done this, you are done with the reset.Shut off the engine.
There are a few points you should remember.One important point that you should remember is not to reset the engine control unit when using different fuels than you normally use.When using anything in your car that you normally don't use, the idea is not to reset theECU.The conditions that theECU would normally encounter should be prepared.The number of resets would be reduced.
If you are going to change the operating conditions on a long-term basis, then you should reset your electronics.It could be when you think of boosting octane.
It's necessary to reset theECU when you boost Octane because yourECU has a memory bank.
If you've been using lower octane, the response of the engine will correspond to the booster's performance.
Even though you have started using higher-octane fuel, theECU response will still correspond to lower octane.This is due to the fact that theECU has not been reset.Even though higher octane is being used, the data in theECU memory still matches that of lower.You can't derive the benefits of boosting the octane due to the mismatch.When you fill up a full tank, you should reset yourECU periodically in order to make sure that the adjustments for the octane in the memory are in line with the actual use of the car.
You can modify the resetting of yourECU so that it can adapt to seasonal changes.You could reset theECU to adapt to the variables that affect performance.
Your car performs the best when it's in a good condition.This can be used in your car at no cost.
The task of timing the spark was done by a mechanical distributor.
The timing would advance if the RPM was greater.It seemed to work well despite being clunky and mechanical.
For the most effective power, you would need to vary the timing to a greater degree than a fixed ratio advance curve.
Control over fuel delivery and spark timing was given by the electronic ignition system.You had a perfect spark timing only in a limited band.
A map of variables was entered into the program and the preset timing would be read from a table.
It is possible to achieve the maximum power output throughout the rev range by controlling the air temperature, engine load, and fuel delivery rates.
The manufacturer can fine tune economy at popular road speeds of 30mph, 56mph and 70mph where most cars spend a lot of time.Some manufacturers in the cheat software scandal created code to detect test conditions and run super lean to pass emissions limits.
If the throttle is wide open, it's possible to advance the timing if you want to improve the economy.
They don't want people to break down, suffer premature parts failure or get a reputation for uneconomical cars so they build in a wide margin of tolerance.Different countries use different grades of fuel and have different degrees of extreme weather conditions, all these factors add to the fudge that has to be done to keep all the cars working well across the globe.
Each car that leaves the production line is unique, some achieve less power than others, depending on how well the components are made and put together.They don't put each car through a unique assessment and instead use a standard one map that fits all philosophy.
It's a fact that manufacturers use the remap to produce different power versions of the same engine and get lower insurance cover ratings and better fuel consumption.When you add in the fact that the average TorqueCars reader will be adding better performing components to the car, you have a really strong case for a remap.
The possibility of user neglect is one of the things that the manufacturer builds in to their map equation.There are items that struggle like dirty plugs, bad leads, and partially blocked injectors.The list continues.
A remap is a good idea for anyone who has added performance parts to their engine.If your car has an electronically controlled fuel injection, there are massive power gains on offer and a remap is a good idea.
What are the hidden costs?Sometimes decreasing the service interval by half is necessary to keep the car serviced more frequently.If the map was designed to make you fill up with high quality fuel and even high octane fuel, you must be prepared to replace components that fail due to the extra work they are doing.
When an engine is revved up to produce more power, you are also creating stress and strain, which will cause air flow sensors to fail.After a remap is done, there are usually weak spots in the engine.At this point, the weaknesses will manifest themselves clearly.You will find that the clutch lasts a shorter time if you don't take care of the components.
If you don't have a turbo there's very little to be gained by a remap alone - perhaps only a few BHP so TorqueCars' recommendation is to modify everything else first.
Because of this, a remap will often introduce boost from lower down the rev range and this will cause the engine to run hotter and faster.If you don't let the engine cool down a little before shutting it down, the oil will degrade and you will have an expensive repair on your hands.A timer will help with this problem and keep the engine running.
Reliability and cost of running the car are affected by the amount of power you choose.Many people go for an off the shelf remap which is on offer all over the country and costs around $600.
This is better than the manufacturers map in that it uses tighter parameters, but it is still a one size fits all.If you have done extensive engine work and changed major components like the waste gate, then a custom remap is the best option.
It is now possible to have a few maps stored which you can choose from.It is normal to have a valet mode to stop the boy racers at the garage from ruining your pride and joy on the "test run" to bed.When cruising on long journeys, there is an economy option to give very frugal fuel consumption.
You have the'sport' or 'power' modes, which give lots of power, and often require high octane fuel.If you want to get the best of both worlds, you should get a switchable remap - it may cost a little more at the beginning, but it will be worth it in the long run.
Some maps use the cruise control to choose a map, other companies offer handheld flash devices which allow you to chose a range of maps and upload these.It takes about 3 minutes to flash a car through the port, so it's not an on the fly option.
After running an economy map through the weekly commute, most people will go for a performance map at the weekend or a race map for track days.
If you want to fool the car into thinking the air is cooler than it is, you should not confuse a remap with the little boxes you can buy for $60.If it was easy to get more power from a car, the manufacturers would already have done that.
I remember that some cars are not easy to remap, like the Rover and ToyotaECU's.The manufacturer has a key to the engine.SomeECU's are not reprogrammable.What can you do?Is there an alternative?It's good to know that they are called "pinch back" or " aftermarket"ECUs.
The engine sensor inputs and outputs are connected to the existingECU.All work differently and apply some or all of the following combinations.
Air temp, engine speed, crank position, and other sensor readings will be adjusted by some in order to force a more aggressive timing.Some people will actually perform their own calculations and take over some aspects of engine management.
Some will take the standard output and modify the signals sent to change timing and learn to guess the next output a split second before it is needed using the baseECU map.
New tuning boxes give extra power or economy by altering readings.
The functions associated with the car'sECU can be taken over by the AftermarketECU.They are able to cope with a wide variety of additional factors, such as water/methanol injection.
Knock protection is not included in some aftermarket and piggy backECUs.If this is the case, set your timing conservatively and use high octane fuel.
Don't chip too early, there is no point in getting a new ECU program early in your engine build up and then later upgrade to bigger lift and duration cams, larger injectors, bigger fuel pump, etc.These parts render your new program obsolete and useless.The power gains from the chip are eliminated.If you later plan on going for bigger and better things, please don't reprogram your chip just after I/h/c/e.It's supposed to be one of your last modifications and not your first to prevent the need for multiple chip reprogramms after each addition of a new modification.Why do you see so many chips on eBay?Other enthusiasts made the mistake of buying a chip too early that wasn't programmed correctly for their engine package.It probably made their engine run too rich, or it made little power for them.They are trying to recover money that was lost from an incompatible chip.There are programmers who take advantage of import enthusiasts who don't understand the difference between a pre-programmed, mail-order chip versus a chip tuning and programmed on your car at a dyno.They are selling them because of the attractiveness of convenience for people who don't have a local programmer, the hype ofhp gains from magazine articles or ads, and a lower cost compared to other significanthp gain modifications, like cams or an intake manifolds.
Your other CEL error codes are also activated by the ECU.When you get a new chip, the program's commands of the ignition map and fuel map are changed in response to a change in air flow.Both are indicators of the engine's load.For a given air flow and rpm, the amount of fuel delivery is changed compared to the stock program.The CEL warning codes can be removed and the VTEC point, redline, and speed limiter points can also be moved.What do these commands look like?An example of a 3dimensional table of program commands is the Manifold Absolute Pressure or MAP.
The 3-D fuel map has Intake Manifold Pressure, RPM, and Fuel Values instead of spark Advance.
Fuel values for the injector duty cycle in the table cells, as well as RPM down the Y axis to far left, are included.
I call them "one-size-fits-all" because a program that will fit as many different engine combinations as possible is the best guess a programmer can make.You get in the no gain or 5% disappointment gain ballpark with these.You won't get a lot of gains with these chips.Save money.
You want to make a lot of power gains.Do you mean 13-15% or at least 7 whp?
If you want to get a true custom chip, you should use a wideband exhaust O2 sensor and Air:Fuel Ratio meter.If you are serious about getting the most out of a computer program upgrade for a street/race setup, this is the only way to go.If you received your chip by mail, please be aware that you did not get the most out of it.The only correct way to reprogram is on the dyno.Which one do you go to?If you are lucky like me and have a couple of local programmers with Honda experience near your town, your local programmer will go with you to the dyno and work his experience in tuning on the laptop and EEPROM burner.If you don't have a local race shop that does programming, you should get together with some friends and invest in a Hondata Stage 4 or P200 system.You can use elapsed times between known rpm points to tune your car.It has a chip burner, chips, instructions, and tech support.Investing in a wide band O2 sensor is a good idea.It takes the guess and disappointment out of the upgrade.If you want to do it on your own, an AEM EMS is worth looking into, since it has base programs and laptop emulation.This is an investment for serious people.
If neither of these appeal to you and you insist on getting a mail order chip knowing that it won't be the best program, then stick to the known programmers (PM me if you want recommendations from people I've known who do a decent "best guess" chip).Most people who buy a mail order chip have a piggyback tuning box that can be used to tune the fuel delivery on the dyno with a wideband O2 sensor.
A wideband universal exhaust gas oxygen sensors (called an UEGO that you can get from a race shop) are required to measure air:fuel ratio at eachrpm.Even if you are experienced at partial and wide open throttle fuel tuning, you will need at least 3-4 hours to tune these.
The Motec M4 is one of the systems to consider.Compare processor speed, available baseline programs, sensor compatibility, and a good track record for tech support/customer service, not just whether they have one or not.
The only way to get more power is to increase the flow of air through the engine.Chips can't do this.They can't make a big difference in power output.At the expense of lowering the factory safety factors for detonation and emissions, chip reprogrammers can richen the mixture slightly at full throttle and advance the ignition timing slightly.The maximum gain would be on the order of 5% and could be as little as zero.Performance chips for naturally aspirated engines have shown minimal or no gains in acceleration in most independent tests.
Raising the boost pressure can increase power in some cases.You risk engine damage if the factory detonation limits are reduced again.If your engine does not have a knock sensor, you are asking for trouble.
The chip companies are doing "custom" chips.What does this involve?If your engine has the same mechanical mod as the motor on their dyno that the chip is being developed for, this is a technically sound modification.The chip won't work for your engine if it's different.Under certain conditions, a chip made for an engine slightly different from yours will be incorrect.Poor driveability and performance can be the result.
The best way to reprogram your computer is to program it on the car's dyno, rather than buying a "best guess" chip that will fit as many different engine packages as possible.
The only way to get good results on a modified engine with different mod from the base engine is to take your vehicle to the tuners facility and get a true custom chip burnt for your engine.This must be done on a dyno and then tested on the road for driveabilty faults which often don't show up.This will cost more.
Here is some good advice when buying a pre-programmed, "mail order" performance chip from SDS' website that I have found to be true.
If you want to buy, do acceleration testing with a stopwatch, Vericom or GTech Pro.If you want to compare to afterwards, you need an objective measure of performance as your baseline.
Get the chip maker to guarantee the performance gain in writing, and make him understand that if he doesn't get it, you will return it to him.If emission compliance is a concern, ask if their chip will pass the test and get it in writing.
Don't go to companies that are bad.Some people in the chip industry don't know what they are doing.Talk to people who have used a certain chip and see if they are satisfied.
You should test your car to make sure you got what you paid for.It's a good idea to get good advice when buying aftermarket devices.A performance gain is advertised.
If it doesn't do what it's advertised to do, you'll get hosed and have some chips costing hundreds of dollars.This is something that you shouldn't think about.
Be careful.Some unscrupulous programmers will promise to sell you a "Mugen" like chip but in reality, all they have done is moved the redline higher and removed the CEL warnings.If you plan on mail orders, the advice is to stick to known programmers.
If the chips don't sound good to you, the alternative is a stand alone engine management system.You can tune your engine yourself.This can be either good or bad.The same thing applies to the mail order chips.
If you don't have a good understanding of the system, engines and tuning, you should not buy one of these.
You will have to program all of the values to make the engine start, warm up, cruise, accelerate and run at full power.This can involve entering hundreds of points in most cases and you will need either a dyno or a long deserted road to properly tune such a system.The systems are a nightmare for the lay person.
If you want your engine to run properly, you have to enter the correct values for the chip that you buy and the one that's in your program.
The main advantage of stand alone systems is that they can be quickly changed if a mod is done or not quite right, whereas the factory type chip must be changed or sent back to be redone.
Don't bother with the factoryECU or chips if you are considering a strictly race situation.You won't get the kind of power required with these because they were not designed for performance use.There is a need for a system that can be programmed.
Make sure the system does what you want it to do.You can't expect a 400hp, 4 cylinder street car to have factory driveability, fuel economy, emission compliance, a smooth idling or long life on pump fuel.No one will talk to you if you do.There are no factory cars like this in your neighborhood.
It can be difficult to remove the factory system and install a stand alone system.What skills will you need to install the system?Are you able to handle it or do you know someone who can?
If emission legality is a concern, find out if their system is legal and if it will likely pass in your area when properly programmed.Many systems are not legal for street use and many manufacturers can't control the programming.
Find out how easy it is to program the unit.If it's hard to use, don't buy it or find a place where you can have it fixed.
Don't blame the system maker if your system is too lean and you melt your engine.You are probably asking the system to do something that it wasn't designed for if the engine runs like that.This is your problem right now.
Follow the instructions.Listen.It will save you a lot of time.The people who design and build this stuff know a lot more about it than you do.
If you sell the present car and buy a faster one, you will be happier in the end.
Data and program information can be found in small chips called ROMs.The chips are 1.5 inches by 0.6 inches.We need to replace the factory data with our own if we want to change the program information.There are different types of chip that can be used.
Once programmed, roms cannot be re-used.There are Atmel AT 27C256 ROMs.The final tune for an engine is not going to be altered.
The only difference between the two is that the EPROM has a window which allows it to be erased and reused.It is suitable for the final tune.
EEPROMs can be erased and re-programmed very quickly.Atmel AT29C252.The advantage of EEPROM is that it can be programmed in 20 seconds.When tuning a car, EEPROMs are the most suitable for use, but can also be used as the final tune.
An epam is a device which acts like an mp3 player.A laptop or PC can be plugged into the box of electronics.The tuning information in theECU can be changed quickly without the need to swap ROMs.
There are two types of emulators, normal and real-time.While the information in the ROM is updated, normal EPROM emulators will shut theECU down.You can change information while the engine is running.
There is a part number on the side of the car's electronics.e.g.The part number has three components.
Honda's part number is 37820 Three characters, which is related to the model of car/engine.Three characters are the revision of the ECU.A00.
The same characters may be used by different generationECUs.e.g.There is a difference between a P72 I and P 72 II ECU.
The PM5 is for the all makes of the Integra, Civic/CRX, SOHC, and ZC.There are 97+ US Acura 1.6EL PCT and 98+ JDM ITR / CTR PCX.S2000
Honda'sECUs have a software revision number inside of them.The main processor has a two or three digit number stamped on it.A letter and number code can be used in Accord and PreludeECUs.
Make sure you match the injector impedance if you are replacing it with a new one.The bigger injectors tend to be less accurate with their fueling at low durations because they take a finite amount of time to open and close.
How quickly it can open and close depends on the mechanics of the injector.You can't tell the difference between stock and larger injectors when you reprogram the ECU for the larger ones.The size of the stock injectors has been increased by up to 4 times.
The assumption is that you aren't re-calibrating theECU to the new size.The bigger injector will over- fuel if you don't.The ECU will use closed loopo peration to reduce the duration of the injection.Close to the increase in size from stock to 310cc injectors is the limit of the long term closed loop adjustment.
Some people prefer to push the limits of the current injector they have by cranking up the FP and running at near or over 80% duty cycle, instead of buying a proper size injector to get more peakhp.The ECU fuel map calibrations for the program are no longer applicable if you exceed a 20% increase from the maximum FP spec.Extra high FP has other disadvantages.
If you push FP or run high CR or boost, then you will need an upgrade to the fuel pump, and if you exceed 310cc/min, you'll need a re-program.
There is a brief introduction to how to tune a sample car map file.
This is only an introduction to tuning.There are many online forums on how to modify map files.
The stockECU load can be downloaded from the vehicle.The application and operating system code for theECU is depicted in this image.The car runs on it's own.Constants and Maps can be found above the code area.The figure is below.
In the Inspector window you can see "Float 250", which is highlighted in the hex dump window.
250, 500, 0,0, 9, 800, 1200, 1600, 2000, 2400, 2800, 3000, 5000, 6000 and 6400.
The values 200 and 500 are not based on the magnitudes, they are more likely to be used in a map or table.
The numbers in red are the RPM values, the green are Mass Air Flow and the yellow is the fuel injector pulse width.
You can find this table by looking for ascending RPM values, ascending MAP values and many fuel injector pulse values.This is a hypothetical map.
We don't know if the start of a fuel map or a timing map is the result of the ascending RPM numbers or if it is a map to control oil injection.
A 32bit float would be 9000 for a standard transmission car or 7500 for an automatic.
Not all values are stored as floats, there are also single byte values of 0-255.