I would like to elaborate my views on the technical points that I personally understand, for reference only:

The driving computer of the EFI Harley car is the “heart” of the car. The driving computer here is actually the engine control module. The English full name is Engine Control Module and the English abbreviation is ECM. It calculates the reasonable air-fuel ratio and ignition angle in real time according to the return values of various sensors on the car (oxygen sensor, gear sensor, throttle position sensor, temperature sensor, fuel sensor, etc.). Volumetric efficiency table and other data and then transmit the corresponding instructions to each executive equipment for operation.

To sum up, if the intake, exhaust or intake and exhaust of the original vehicle are changed, it is suggested that the ECM should be adjusted at the same time, otherwise the air-fuel ratio may be too thin, which may lead to the increase of engine temperature, and there will also be some problems such as fuel return during cycling. After the adjustment of ECM, the above problems can be solved. Which adjustment methods will be introduced next? However, if only the exhaust tail section is changed, there can be no computer adjustment.

Common ECM adjustment equipment can be divided into “plug-in”, “rewrite program”, “replacement” three types (my classification name, make do with it). This order is basically low to high price, but also adjustable from low to high order.

“plug-in”:

The common external computers are Cobra Fi2000 and PowerCommander (commonly known as Power Commander). There is no need to connect the PC computer to set it up, as long as it is installed and connected in series to the corresponding position of the original car circuit, the plug can be plugged in, it can be removed at any time, the installation is effective, and the removal is invalid. It is not locked with the car’s VIN, so it can be used on other vehicles.

By deceiving ECM, the plug-in computer sends the fake sensor data to ECM to make the engine run in a state close to the correct air-fuel ratio. The plug-in computer has a fully automatic version, a manual version, and a manual version with three knobs, corresponding to the air-fuel ratio adjustment under low, medium and high engine loads or low, medium and high throttle opening. Therefore, the plug-in computer can be used to solve the problems such as ECM matching after refitting, reducing the engine temperature caused by the modification (sparse air-fuel ratio) and so on. It can only adjust the air-fuel ratio, not other adjustment settings.

“rewrite the program”:

The rewriting program type computer is to rewrite the internal software program of ECM to allow ECM to control the engine operation according to our parameters under the condition that the hardware of the ECM of the original car remains unchanged.

The common rewriting program type computer has PowerVision,Screamin’ eagle,VH FUELPAK these three kinds of brand equipment. Rewrite the program of the computer can adjust idle speed, air-fuel ratio, ignition angle, speed meter, gear conversion, open-loop closed-loop temperature setting, lifting the maximum speed limit and so on almost all can think of parameters, at present, I can only think of except can not modify the VIN code, can not reduce the idle speed below the 800rpm (original computer hardware limit) properties can be set.

I have been using is also recommended is PowerVision, which consists of a touch screen, can be used as an electronic instrument display, can read and clear the fault code, of course, the most important thing is to set ECM parameters, corresponding to the intake and exhaust brand download the corresponding preset tune program to write ECM to complete the modified program settings, or through the specific speed, cylinder pressure to use PC computer to set more accurate and exquisite adjustment program parameters. Unlike plug-in computers, rewriting computers are locked with the car VIN. As long as the device is connected to a car, it is locked with that car and can no longer be used for other car rewriting programs. PowerVision can be unlocked by paying for a license at this stage, that is to say, you can adjust the program for other cars after paying for it. Of course, each car needs to be unlocked separately.

Just connect it to the diagnostic socket of the car, and you can remove it after the operation of rewriting the ECM program (the writing process is about 1 minute). It can also be used in the car as an “electronic instrument”. Either removal or connection will not affect the completed ECM adjustment. It also provides an automatic mode Autotune, which automatically corrects parameters such as air-fuel ratio according to riding habits and the return value of the sensor for intake and exhaust, which can be automatically corrected after two or three 20-minute rides. Of course, the device can be removed after correction. Automatic mode is divided into Basic and Pro, based on the original narrow-band oxygen sensor is Basic, slight modification and low-and medium-load riding have a certain correction effect. Pro mode should cooperate with its additional broadband oxygen sensor and AutotuneTarget module to complete collection and correction, it can adapt to all types of intake and exhaust and your cycling habits, and can automatically adjust a perfect program.

In addition, if you upgrade the displacement such as 883cc / 1200cc, change the sprocket to change the transmission ratio, modify the camshaft, etc., the rewriting program computer can adjust and match the corresponding program parameters, which can not be done by the plug-in computer.

After playing for such a long time, I have a thorough grasp of the use of Powervision computers, which can help riders adjust ECM, optimize performance, and leave messages for communication. Later, I will write a detailed tutorial article on the use of Powervision computer, welcome to follow.

The rewriting program computer Screamin’ eagle is used differently from the Powervision. It needs to connect the vehicle and the PC computer at the same time, rewrite the parameters through the software of the PC computer, and then write the parameters to the ECM of the car through Screamin’ eagle. Also lock the car’s VIN number, can not be unlocked for other cars to use. There is also an automatic mode called SmartTuneLive. For Screamin’ eagle computers are not recommended, I feel it is not easy to use. Basically only Harley 4S store is in use.

The rewriting program VroomH Fuelpak computer is used in a different way. It connects with the APP of the mobile phone through Bluetooth. All settings are carried out in the APP of the mobile phone, and the app side can also be used as an “electronic instrument” to display various parameters of the vehicle. Similarly, it locks the frame number and cannot be unlocked for use by other cars at present. It is convenient to use, and the adjustment of ECM can be completed by selecting the corresponding information such as intake and exhaust. You can also remove ECM after rewriting it. It also supports automatic proofreading adjustment. I personally think it is more convenient to use, but the degree of freedom is slightly lower according to Powervision, and the editing and program backup on the mobile phone are not flexible. If you want to solve the computer adjustment after retrofitting into the exhaust, recommend fuelpak, basically can be done with mobile phone app.

“replacement”:

A common replacement computer device is ThunderMax, which directly replaces the original vehicle ECM and narrowband oxygen sensor installation. Installation is relatively complex. The same use is similar to Screamin’ eagle, you can only use a PC to connect to the vehicle for joint debugging. Because it is a replacement type, there is no such thing as locking the VIN code. When changing the car, you can exchange it for the original car ECM and transfer ThunderMax to others for use.

The replaceable computer has the greatest degree of freedom. In addition to achieving the same functions as a “reprogramming” device, it can also set the frame VIN code (what can it do? For example, if you collect a second-hand meter and the meter locks the frame number, then you can use the watch by changing the VIN setting in Thundermax to the same VIN of the original car. If you are embarrassed, cover your face.), It uses a broadband oxygen sensor, which can fully adapt to various engine operating conditions and ensure the best air-fuel ratio and other settings at any time. At the same time, it adjusts the idle speed no longer limited by 800rpm, and can adjust it to 600, 500 or even lower. Coupled with fine tuning of other parameters, the simulated horseshoe sound is still very similar. However, due to the different loads of the original vehicle oil pump and the vehicle’s power-consuming equipment, too low idle speed may cause insufficient oil pressure, battery charging cannot meet external supply and other problems. Therefore, you must be cautious when lowering idle speed. Because of its large degrees of freedom and complex adjustment parameters, it requires more professional technical mastery to play and is not recommended to use it.

Because there are many sensors on the vehicle to provide operating reference for the ECM, the ECM can automatically adjust to adapt to various working conditions under certain circumstances. But what does the “narrowband” sensor used in the original factory configuration mean? It can be simply understood that the sensing range of the narrowband sensor is small, and it can accurately sense the oxygen content in the original exhaust. When the exhaust gas is replaced, it cannot accurately sense the oxygen content under certain loads, and the ECM of the original vehicle cannot accurately calculate the data and issue precise instructions. So wouldn’t you just switch to a “broadband” sensor? Direct replacement cannot be done. The original vehicle ECM does not support it. Either a module is installed between the broadband oxygen sensor and the ECM or the ECM is replaced with a replacement computer.

So to sum up, it is recommended to try Fuelpak if drivers want to adjust their own intake and exhaust models. It is recommended to try Fuelpak if they want to advance the ECM adjustment together with some or several partners, or it is recommended to try PowerVision for multiple vehicles.

Okay, that’s basically all about Harley ECM computers. Welcome to leave messages and communicate. Welcome to pay attention. If you think my writing is good, you are welcome to reward and support me.

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