well think of a tuner as a laptop that you own. You write a word document and save it. That word document is the same as if it were to have been created on some other laptop of a different brand right?
So a tuner is like a laptop. It does something~ they all do the same thing.. .update your car's tune file. The end result is pretty much the same for all tuners. The only issues is some tuners allow better data logging or allow you to modify specific parameters others wont... so in the end they are all pretty much the same and do the same thing.
Now with that out of the way, when a tuner is used it is "locked" to that car ,that means only that car can use it. You can have them unlocked either by removing the custom tune or paying someone to unlock it. If yours is unlocked continue on.
You have the tuner but... now you have to have a tune file loaded onto the tuner. I mean, you have to update the car with something~ thats the tune file. Some tuners come with default base tunes called "can tunes" that are just updates that are not optimal but do make a difference.
Does your tuner have tunes on it that you can use? Some tuners dont come with tune, you have to buy a tune and put it on it... you cant use it until you do.
Take me for example, I purchased an SCT Tuner and it had no tunes on it from the manufacturer, I went to the tune menu and it was blank since there were not tunes to select from. Once I got it I contacted RWTD (a business that writes tunes for my car) and had him write me a tune. He emailed me the file and I saved it on my desk top.
My tuner has a USB cord, I pluged it up to my computer and downloaded the SCT software that allows me to put a custom tune on my tuner. I entered in the custom tune and clicked upload and "BAM" the tune is now on my SCT Tuner.
Now that thats done I just plug the tuner up to the car and click the tune menu option and tell it to use the tune I have.
Then im done
so basically, is your tuner unlocked?
Does it have custom tunes on it for YOUR type of car?
If you require a custom tune (the best kind to get the most power out of your car) I recommend finding a tuner you trust that can write tunes for your tuner type (Diablo going by what you said) and take the car to them. They can dyno it and what not and give you a custom tune file for your vehicle. Some people are quite good at writing tunes and can send you one in the email that is very close to optimal. A dyno always ensures the car is safe and can be used to fine tune the car.
Data logging is also useful~ basically you record everything the car is doing under different circumstances... like 1000rpm to 4500 rpm with half throttle, just idling, or full throttle and the tuner can view those records and see how the car is doing.