Some of the best engine tuning tips I can give you have precisely nothing to do with tuning. In this article, we’re not going to talk about the impact of richening up your mixture, nor are we going to debate adding 1 psi of boost versus 1 degree of timing. We’re not going to get into the physics or science of tuning at all. Instead, let’s get fundamental about the fundamentals.


“All I did was change a bunch of stuff and now my car doesn’t run.”

This is a statement I see way too often. Someone gets very excited and starts turning all the knobs they can. And then they run into a problem, and when they do, it’s too late. They can’t back out the last change and go back to the previously running state because they’ve made many changes and have no idea which change was the bad one.


Here’s how to do it right:


1. Make ONE change at a time!

Remember ‘the scientific method’ from High School Science class?  This sounds so basic, but I can’t tell you how critical this is.

If you make 2, 3, 4+ changes at once, how do you know which change created the desired result, or possibly the undesired one? Road racers and autocrossers will know this adage: Go slow to go fast. Don’t get ahead of yourself, take your time, and let’s deal with issues when they are created.

Note that I said when, not if.

2. Save your tune! Again!  Again!!!

And don’t just save it under the same file name. Use the File>Save Tune As function and give each tune a unique name. I’ll even tell you my personal system. I give each tune a number, and move up sequentially. After the number, I list a brief description of the change I made.

For example, let’s say someone drops off a running car. The first thing I will do is save the customer’s tune before I make any changes. I will label this, “000-As Presented”. After looking the tune over, and assuming that everything looks reasonable, the next thing I may do is verify base timing. After verifying timing and properly setting tooth #1 angle, I will save the tune as, “001-Set base timing”. My next change may be re-scaling the VE table, which would be saved as, “003-scaled VE” and so on.

Why ‘001-Set base timing’ instead of ‘1-Set Base Timing’?  Because it will sort the files from 001-999 as you progress and make it much easier to find your files later.  Just trust me on this one, or try it.  You’ll see why it’s helpful.

That said– You don’t have to replicate my system exactly, but using some sort of system will allow you to always revert back to a known good tune if you run into problems created by engine tuning mistakes.

3. Power cycle the ECU any time you turn a feature on or off.

No, most features don’t require you to do this. BUT– it can be helpful particularly if you’re enabling features that could possibly conflict with another feature.

So I recommend you do this even if the Engine Control Unit does not prompt you to do so. If you turned a feature on that is not compatible with other settings, the self check on boot up will tell you right then and there about the problem. There’s no getting surprised later, and there’s no chance of potentially unwanted behavior. This also applies if you change a pin assignment. For instance, if you move your 2-step switch from Digital Input 1 to Digital Input 2, power cycle the ECU. This way, the self check feature will validate that Digital Input 2 is going to work for the input. If you also had Digital Input 2 (DI2) assigned for a different feature, such as for table-switching, an error message will appear. There are no surprises this way.  And you find out now, while you know what exactly introduced the issue, not later after maybe you’ve made 5 other changes and are less sure what caused what.  Back to the scientific method.  Back to Rule #1 above.

If you find that you double assigned an input and created an error, don’t panic! After all, if you followed the first and second steps above, you can simply revert the last change or load in the last known good tune. You’re just a few mouse clicks from running again.

4. Datalog everything!

When you are tuning your engine, data is power. What did that last pull you made look like? Did it pull clean, or was there some sort of hiccup? If the latter, you are shooting yourself in the foot if you don’t have data to comb over. Data can show you if there is a problem with the crank trigger, or if you were running excessively lean or rich, or if you were protected by over-boost shutoff. Save each datalog, using a sequential numbering strategy similar to how you name tune files. I usually will run a single datalog during steady state dyno tuning, but when it’s time to start making power pulls on the dyno, I will often save a new datalog for each power pull.

Further, if you find yourself running into a wall and you reach out for technical support, you will need to provide a datalog (.msl) demonstrating the issue as well as the tune file (.msq) that was loaded at the time of the issue. It’s best to have this data instead of having to take another pull, potentially putting your engine at further risk.  Go ahead and have that data on ready in case something happens you’re not expecting, and often… you can see what happened.  And if you can’t, we probably can help.

5. Use your on-board safety systems

Lastly, MS3Pro Engine Management has numerous engine protection strategies aka engine safeties available to help protect you against catastrophe. Don’t be afraid to use these tools. They include protections for over-boost, wandering too far off AFR targets, excessive EGT, and more. These tools are there to save your wallet. Use them. There is a lot to watch when tuning, and even tuning veterans can be overwhelmed with the amount of data that has to be continuously monitored. Let the ECU help you.

Here are a couple articles that may help regarding these engines safeties:



Everything written here is common sense, but I’ve never heard any of it talked about in formal EFI training classes, and I see the ramifications from people not following these recommendations daily. Following these basic guidelines should save you time and frustration. Go cowboy at your own peril. I hope that you found the information in this article helpful. If you have questions, comments, or feedback (good and bad!), please send me an email: [email protected]

Ben Berusch
DIYAutoTune Technical Support

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