Originally Posted by Concillian
I installed ID1000s in my car that originally had ~440cc injectors and drove 15 miles before they were tuned, I know what I'm talking about. Not because I needed to drive to tuner, but because I broke my Tactrix while I was doing installs and needed to take someone to the hospital while another was in the mail.
His car won't blow up. It might run rich and throw a CEL because it maxes the fueling trims, but nothing bad will happen. It WON'T be injecting 750 / 440 = 1.7x the fuel. There's over 25% adjustment range via fueling trims in the ECU. At most it'd be injecting ~1.25x the fuel it should be, but since cruise is 14.7:1 and you have until like 10:1 before you have any real issues, the only thing you need to do is not push the pedal down too much so the ECU switches to open loop fueling.
If you're really paranoid, find a local with a Tactrix and give them $20 to change your injector scale to 700 from whatever stock is. That'll be plenty to get the ECU close enough to get you from point A to point B without a tune and be rich enough to be plenty safe too.
I installed 565's in my car and started it and couldn't even push the gas pedal without the thing dying on me. But I digress
The easiest thing to do is get a basemap uploaded. It's soooo easy! You could even ask the tuner if you could borrow his tactrix or something.