[Stl_95]

as the title states, i installed a diablo tune on my 01 Gt, i did not reset the handheld unit properly, so the pre existing tune for a 02 5 speed Gt was downloaded onto my ECM or Computer, and now my Car will not Start, but i also installed the "Factory Hp" setting and it ran?, now it only goes click like the symptom of a dead battery when turning the Key, the dome lights, horn, and dash lighs all work so what could it be? i also disconnected the battery for 15 mins, do i have to have my Main computer restored or flashed? and if so how would i
?

 

[heavy metal]

Welcome to the site!!

 

[wmburns]

I just don't see how a bad tune could cause symptoms like a bad battery. There isn't any method for the 99-04 MY Factory PCM to "lock out" the starter. So even IF the PCM were totally dead, the starter would still crank the motor.

My vote is to rule out a loose/bad battery cable, blown/loose fuse, or loose ground before looking any deeper. Pay special attention to the battery negative as it's bad about splitting when over tightened.

Here's a Crank with no start check list that may offer some additional help.

http://www.allfordmustangs.com/forums/4-6l-tech/336452-1997-mustang-wont-ignite.html#2984838

 

[rccg94]

If it's not already fixed another common issue consistent with what you describe is the starter relay. A quick and easy test is to swap it with the fog light relay as they are the same part #. You'll know in less than 5 mins if it works. I even went through the trouble of bench testing my relay and it seemed OK but I was not pulling near as much current as the starter motor would be with my continuity tester! Good luck.

 

[Tominator]

I've heard many times that if you use a tuner to make very sure the battery is at full charge. I'd put a charger on it for an hour or jump start it. If it starts, look at the possibility of a weak battery or other component.