What causes a 2001 ford mustang 3.8 to not start?

Answer 1

the most provable causes in my exp. is one of the below,

a bad key lock assy. to diag just replace sometimes they work half the time and realy is no other way to determine fault

a bad fuel pump. to test spray A SMALL amount of pyrol starting fluid in throttle body with throttle plate open but do not try to pump the gas if it only starts and trys to shut back off its normal starter fluid burns quick.if it starts from fluid you have a bad pump.

if not go to a junk yard and get a couple enirtia(fuelpump cut off) switches at least 3 cause only about 1 in 3 actually works so don't make 2 trips. take time to do this cause i have seen many service bulitons on those. so don't be eager to over look this switch can be tricky to figere out if bad and make shure you have voltage there too.

does your secrity light blink after you turn the ignitionm on if so you have a bad transiever witch is a very common problem with those

next to check would be coil pack or crank sensor, a lot of those ckp sensors will make little chirping noise on every engion rotation before they totaly fail thsts for cam and crank.