When first incorporated into internal combustion engines, Electronic Control Units (ECUs) controlled only the air and fuel mixture and ignition timings. In modern vehicles, ECUs manage the entire engine performance and overall operation of the vehicle. The ECU is a computer coded to control everything it receives from many sensors and ensure the engine runs properly. It processes the data it gets and sends appropriate commands to the individual components to optimize engine performance, fuel efficiency, and emissions monitoring.
Automobile enthusiasts always seek to improve their vehicles' performance. Many performance mods exist, but almost all require tuning to the ECU to utilize them fully. ECU tuning involves modifying the unit’s settings to improve the power output and fine-tuning the parameters according to the other mods you’ve done to the engine.
ECU tuning involves modifying software or firmware within the unit's chip to alter the engine's operation. ECU tuners can improve engine performance by changing and modifying many variables, values, and settings. The main focus in performance ECU tuning is to optimize air intake, fuel delivery, and ignition timing.
When you upgrade the engine for more power, you change the amount of air and fuel that goes into the combustion chamber. For instance, fitting a cold air intake kit will increase the airflow inside the cylinder. If you don’t change the tune, you’re not fully utilizing the cold air intake kit. It might bump up the horsepower alone, too, but you have to “tell” the ECU the changes you’ve made. In this case, you’ll tell it to increase the fuel amount to maximize the air-fuel ratio's efficiency inside the chamber.
ECU tuning can be performed on stock ECUs if the manufacturer allows changes, or it can be done by installing aftermarket piggyback units or standalone ECUs. Do not try and screw around with all these on yourself, though. Let a professional engine tuner do it unless you actually know what you’re dealing with.
You already know how an internal combustion engine works. You need three ingredients: air, fuel, and ignition. Then, witchcraft happens inside the combustion chamber, and the engine produces power to propel the vehicle forward. To get the best efficiency and optimum performance, you need the right amount of air and fuel in the mixture, called the air-fuel ratio (AFR).
Manufacturers set these parameters to balance performance, economy, driveability, and longevity. Modifying the ECU will yield much more power than the manufacturer intends, and if you have various other performance upgrades, a proper ECU tune will help you get the most from them.
Performance ECU tuning involves changing the parameters regarding the air-fuel mixture and ignition timing to optimize the power output.
A perfectly optimized engine runs on a perfectly optimized air-to-fuel ratio. Too much fuel makes the engine run rich, and too much air makes it run lean. A lean-running engine produces less power and overheats. A rich-running engine does not produce the optimum power, and you’ll throw fuel efficiency out the window.
The mixture needs to be just right, and any performance upgrade you do under the hood will ruin this balance. ECU tuners adjust the AFR to provide the ideal mixture for performance gains based on the other mods you’ve made to the engine.
When the air-fuel mixture is compressed inside the combustion chamber, you need a timely ignition spark for the best performance. If the spark happens too late, the piston might already be down the cylinder, resulting in low power. If the spark occurs too soon, the piston might have to work against the expanding gasses after the combustion, resulting in detonation. Also, the air/fuel mixture does not immediately explode with the spark, so there should be a slight delay in ignition timing.
Optimal ignition timing is crucial for the best performance, efficiency, smooth driving, and reduced engine wear. Adjusting the ignition timing is a vital process in ECU tuning after modifying other aspects of an engine.
If your vehicle’s engine has a turbocharger, the ECU controls the forced induction system, too. A turbocharger increases the volume of the air that goes into the engine by compressing it. The ECU monitors and manages this process, which is directly related to the air-fuel ratio.
By tuning the boost pressure, you can force more air into the engine, increasing the power output with the help of more fuel injected. Proper ECU tuning ensures the engine operates as safely as possible despite the increased boost levels.
Some ECUs are flashable; you can put a new file into them, but others don't. You can use piggyback ECU tuners that connect to several sensors and trick the stock ECU to change its parameters to produce more power. Or you can get an aftermarket stand-alone ECU and program it for your specific engine build.
These devices connect between the engine’s existing ECU and several sensors and modify the signals from the sensors before they reach the ECU. The stock ECU receives modified signals and is tricked to increase the power output. Piggybacks are relatively easy to install and quite cost-effective. However, the power gains are moderate compared to other, more advanced solutions.
Remapping or re-flashing a stock ECU means rewriting the software to alter its default settings. Remapping can provide significant power gains, especially when combined with other modifications. Remapping is usually done by professional engine tuners specializing in your particular engine through special tools and software.
Aftermarket standalone ECUs replace the stock ECU completely. These are for advanced applications and custom builds. Standalones offer extensive customization and are ideal for high-performance applications such as race car builds or heavily modified street cars. You'll have total control with a standalone ECU, but the catch is your vehicle won't pass the smog test.
Well, this is obvious. Proper ECU tuning yields power and torque gains. Even a tune alone can increase output by optimizing the settings for more horsepower. If you have additional mods, an ECU tune will ensure you get the most out of your upgrades.
A good ECU tune will increase fuel efficiency, especially in turbocharged engines. Your engine will produce more power earlier than stock, which you can use to your advantage. You just need to be easy with your right foot!
Some tuning options (especially piggybacks and advanced standalone units) have different modes you can choose while on the go. You can easily switch between maps and get extra fuel economy or significantly more power.
ECU tuning requires professional help. An engine management system is just too complicated if you’re not trained and familiar with it. Some piggyback units are relatively easy to install, but that’s it; for anything more advanced, you have to find a good shop and an experienced tuner.
ECU tuning is considered an extensive modification, and manufacturers disapprove of such changes. You’ll lose warranty coverage and have insurance issues. Only some piggyback units are easily converted back to stock, and if you remove them before going in for service, your warranty will still be intact. Also, a standalone ECU will not generate OBD II communications, making your vehicle fail the smog test.
There's no “safe tuning.” The safest tuning is what your vehicle comes with from the factory, and any modification, including ECU tuning, will affect longevity. Tuning is all about sacrifices, and you should decide if you’re OK with sacrificing some engine life (very little, if you get a proper, quality tune) for extra power.
Regardless of how much your vehicle has been upgraded, Pedal Commander® will add another layer of excitement to driving. Any performance upgrade will enhance your vehicle’s responsiveness in some way, but the electronic throttle system’s delay will always be there.
Pedal Commander® removes throttle delay and offers you direct and instant access to the engine’s power. It also lets you precisely adjust the throttle sensitivity with its four driving modes and 36 individual increments to suit your needs. You can put it in City for zipping around traffic, switch to Sport+ for track days, or select Eco and enjoy a smooth drive with fuel economy in mind.
So, you're new to tuning and wondering ‘What equipment do I need to tune an engine?’. It’s a pretty straightforward question, and since engine tuning is a specialised job, there are a few tools that you are going to need to help you do your job correctly. Some of these tools are what I’d consider to be essential items that you just can’t get by without, while others such as an oscilloscope will only get used occasionally and might not be part of your initial tool purchase. Let’s look at what you are going to need.
In this article: Wideband AFR Meter | Audio Knock Detection | Timing Light | Digital multimeter | LED Test Light | Oscilloscope | Laptop | Tuning Software and Cable | Conclusion
What we use: Innovate Motorsports LM-2 Dual Air/Fuel Ratio Meter
We’ll start with one of the tools you just can’t get by without - A wideband air fuel ratio meter. When it comes to engine tuning, one of the most critical jobs is making sure the engine is supplied with the correct amount of fuel to match the inlet mass airflow, and in order to know how we’re doing we use a wideband air fuel ratio meter. When I first started tuning, wideband meters were seriously expensive and your options were very limited. These days we now have a range of high quality wide band meters available from several manufacturers and they are very reasonably priced.
Your options for a wideband meter can be broadly broken down into two groups - Permanent install or portable. Your best option will depend what you’re going to be using it for - For example if you’re just interested in tuning your own car, then I’d recommend a permanently installed wideband controller that can send AFR data to your ECU for logging purposes, while displaying the AFR data visually via a gauge. If you’re expecting to be tuning multiple cars then the best option for you would be a portable wideband meter that can be easily moved from car to car. These meters can normally be attached to the inside of the windscreen with a suction cup, and powered via the cigarette lighter socket for ultimate convenience.
It’s difficult (not to mention potentially dangerous) to focus all your attention on the display of a wideband meter while driving so regardless whether you’re using a portable system or a permanently installed controller, it’s worth going to the trouble to hook the wideband up to your ECU or dash so that you can log the AFR data. This lets you safely analyse the AFR data on the side of the road or track and also allows more precise adjustments to be made to the exact area your fuel map was rich or lean.
What we use: Plex Knock Monitor Pro V2 | TunerNerd Knock Monitor Pro
The other key task we’re performing as tuners is to calibrate the ignition timing or ignition advance angle. When we’re optimising the ignition timing, particularly if we’re tuning a turbocharged engine that’s running on low octane pump gas, then we’re very likely to find that the engine begins to suffer from knock. Knock is incredibly destructive and we need to ensure that the engine isn’t suffering from knock while tuning so I’m a strong advocate of using audio knock detection equipment any time we have an engine on the dyno.
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Audio knock detection systems use a normal donut style knock sensor bolted to the engine block, and process the output from the sensor with a digital signal processor. This allows the system to focus on the frequency knock occurs at and this helps reduce the influence of background engine noise. We then listen to the output of the knock detection system using normal headphones so we can audibly hear what is happening inside the engine. When knock occurs we can normally hear this clearly and distinctly through the headset.
There are many professional tuners in the industry who believe that knock detection is unnecessary because if we are tuning the engine on a load bearing dyno, we will see the torque drop off at the onset of knock. While it’s true that the engine torque drops when the engine is knocking, typically we’ll find that an engine begins knocking on just one of two cylinders first, while the other cylinders may continue to show a net torque improvement despite localised knock. I’ve had this situation numerous times where an engine has shown a healthy increase in engine torque as I’ve advanced the ignition timing, despite audibly knocking quite aggressively - Scary stuff if you can’t hear what’s happening!
Many late model aftermarket ECUs, as well as most modern OE ECUs now include some kind of closed loop knock control system aimed at detecting knock and reducing ignition timing to prevent damage. On the face of it this might seem to make audio knock detection systems irrelevant but I disagree - For an aftermarket ECU we still need to calibrate the knock control system and prove it’s working correctly. Likewise with OE ECUs, I’ve struck certain cars where the knock control system either picked up false knock, or worse, ignored knock that could be heard audibly.
Here's a pro tip - Most of the audio knock detection systems recommend or supply at additional cost, an expensive noise cancelling aviation headset. I’ve tried just about every option and have found that I get the best results with a pair of quality iPhone ear buds and a pair of 3M/Peltor Grade 5+ ear muffs (aka ear defenders) over the top.
What we use: INNOVA Timing Light
Another cheap tool that a tuner really can’t live without is a timing light. This is particularly critical when you’re setting up an aftermarket ECU for the first time as we need to calibrate or set the base ignition timing so that the number we see on in the ignition table matches what the engine is actually receiving.
A timing light uses an inductive clamp that fits around an ignition lead, and they produce a flash when a spark occurs. By pointing the timing light at the timing marks on the crank pulley, we will be able to see what the actual ignition timing is. While you can buy expensive digital timing lights that include a dial back function, these aren’t strictly necessary and in some cases can actually be misleading if you don’t understand how they work and their limitations. I recommend saving your money and buying a cheap basic timing light which you should be able to find for around $50 USD.
Most modern engines now rely on direct fire ignition systems with a single ignition coil per cylinder and no actual ignition lead. A pro tip in these situations is to remove the coil from number 1 cylinder and temporarily run an ignition lead from the coil to the spark plug. You can now clip your timing light onto this lead and be assured of accurate ignition timing information.
Take your pick noting the advice below: Digital Multimeter
Now we will move on to some of the more basic tools that are often overlooked yet are hard to live without. One of the most frequently used tools in my tuners tool box is my multi meter or digital multimeter/voltmeter. It would be nice to think that tuning simply requires sitting comfortably in the driver's seat with the laptop, however experience shows that you’re frequently going to strike some kind of trouble while tuning, and when this happens we need to fault find and diagnose the issues - A digital voltmeter is a quick and easy way of measuring voltage and resistance in circuits as well as testing for continuity in a wiring harness.
Digital voltmeters vary dramatically in price but for our purposes we don’t need anything particularly elaborate so we can get by with a cheap entry level unit that can be purchased for around $50 USD or less. If possible I’d suggest looking for a model that has an auto power off feature or you’ll always find you have a flat battery when you come to use the voltmeter!
Take your pick: LED Test Light
Next we have an LED test light. These are a quick and easy way of checking for voltage in a circuit. They are simpler and faster to use than a digital voltmeter, but they can’t give you the same amount of information. For example, the LED test light will show you that a circuit has voltage, but it won’t show you how much voltage is present.
One of the best uses of a led test light is for checking pulse width modulated outputs such as ignition and injector drives. By connecting the LED test light across the terminals of an injector plug, the LED will flash every time the ECU pulses the injector. This is a quick and easy way to prove that the ECU is operating the output. When you are checking a pulse width modulated output like this, the LED test light will only be useful at low frequencies. If the frequency is over about 30 Hertz, you won’t be able to see the LED flash.
Led test lights can be purchased for around $20 USD or less and I consider them to be another essential item.
What we recommend: PicoScope Series - Note you can buy specific models direct and there are also automotive specific models, however they start getting pricey.
When we’re dealing with an ECU, many of the signals will be waveforms where the voltage varies in relation to time. These sort of signals can’t be analysed properly using a simple digital voltmeter and to be able to visualise the waveform we need to use an oscilloscope - Oscilloscopes can show us how a signal or waveform is changing over time. Most oscilloscopes will also allow two or more signals to be viewed and overlaid simultaneously and this is the perfect way to fault find triggering problems
An oscilloscope is one of those tools that you don’t use all the time, but when you need it, nothing else can do the job. Oscilloscopes used to be a moderately expensive tool, however with PC-based oscilloscopes such as those sold by Picoscope while not being 'cheap', they are now much more affordable especially when they save you from hours of fault finding. If you want to take EFI tuning seriously, then you will eventually need one of these.
What we use: Anything with Windows OS, an SSD, plenty of USB ports and good battery life.
Since we need to tune on the road, we are going to need a laptop computer to actually run the software and talk to the ECU. Just about any laptop will do this job and you definitely don’t need the latest or most powerful processor. In fact tuning is pretty hard on laptops and I find they only have a lifespan of a couple of years. It makes sense then to buy a cheaper laptop that you aren’t going to be too worried about if it breaks. I do recommend buying a laptop with a solid state hard drive though as these are much less likely to suffer failure due to vibration and I’ve lost many gigabytes of data when I’ve had a conventional hard drive fail. Often the cheaper laptops won’t offer a solid state hard drive as an option but you can usually purchase generic SSD drives and upgrade at a later point.
I also recommend that you purchase one with at least 2 or more USB ports as you will need these for connecting with both your vehicle and tuning accessories.
If you are tuning some older ECUs, there can be compatibility problems when running on the latest version of windows. Check with your ECU manufacturer before buying a laptop to make sure the system requirements are going to match your needs.
This is application specific.
Often purchased before realising what else is involved with EFI tuning is a standalone ECU or reflash tuning software package. Here at HPA we 100% advise you start learning BEFORE doing this for a few reasons, the two main ones being:
With that out of the way, we are of course still going to help you with this topic here and now. Your course of action will depend on if you are using an aftermarket standalone ECU that physically replaces your OEM/factory unit, or reflash tuning your factory ECU using tuning software. For more information on these two options, check out a previous article that covers them.
For a standalone ECU, it doesn't matter if you have a MoTeC, AEM, Haltech, MAXX ECU, Ecumaster, Megasquirt, Link ECU, Syvecs, EMtron or one of the many other brands out there on the market, your software will be supplied for free with the ECU, or from the manufactures website if you have purchased secondhand. Save for special cases, a run of the mill USB cable will be all you need to connect your laptop to the ECU, although sometimes a shielded cable is recommended which you can get from the ECU manufacturer, or from a computer supply store.
Not sure how to choose the right ECU for your application? Make sure you are logged into your free Bronze account then watch this lesson.
For a reflash tuning solution, the software is essentially what you are paying for in order to decipher and modify the parameters controlled by your factory ECU. This can take years of reverse engineering by skilled software engineers to put together which unfortunately means that not every ECU out there is available when it comes to this option, and it is generally the more popular vehicles for modification or easier ECUs to reverse engineer that are supported because of this. It doesn't matter if you're using HP Tuners, COBB Tuning, Hondata, Ecu Flash, EFI Live, EcuTek, Romraider, SCT or another software provider, any hardware required, either an OBDII to USB cable or propriety OBDII dongle that interfaces with your laptop, will be supplied by your chosen software provider. In some instances, they will also need to physically modify your ECU in order for you to be able to modify the tune files.
Not sure how to choose the right reflash tuning software? Make sure you are logged into your free Bronze account and then watch this lesson.
The last item on our must-have tools list is perhaps the most important. Tuning carries an inherent level of risk and there’s a lot that can go wrong if you don’t know what you’re doing. It doesn’t take much to do some real damage to your engine, and equally it doesn't take much to avoid such situations, so it really pays to prepare yourself with the correct knowledge right from the start.
High Performance Academy’s EFI Tuning courses are the perfect place to find everything you need, as well as practical worked examples to follow along with, and support from tutors and other students as you learn and embark on your own tuning projects.
The best part is, if you find that any of these courses aren’t for you, you have 60 days to return them for a full refund — so what have you got to lose? We hope to see you in our community forums soon.
So that wraps up the main tools you are likely to use. While there are a limitless number of additional tools that can be handy to have, these are the ones that are critical to doing the job right.
For more information, please visit Ecu Tuning Tools.