1990 mustang 5.0 wont start why?

[tunertownz]

i have a 1990 mustang it will turn over but slowly and won start car.... i can push start the car and it starts and runs great.... i have done everything i can think of .... new battery, new 1G cable battey to silinoid, new silinoid, new wires from silinod to starter, new starter, new cap and roder, new spark plug wires , i had altinator and new starter tested along with battery all good... engine is rebuild i drove it about 1k miles then after work one day it wouldnt start.... i had 10-40 oil in it its winter so i changed that to 5-20 so im out of things to do anyone have any ideas??? im stumped...

 

[85ragtop]

Sending this to 5.0 tech.

 

[HISSIN50]

How are your ground cables?

If you turn on the headlights, do they come on and stay bright?

If you use a jumper battery, does it crank faster?

 

[90limited]

+1 on the ground connection to the block...

 

[nisreo]

bad engine ground will probably make the car run like crap and buck in higher rpm. I forgot to tighten mine and the car started and idled fine, then got all messed up when I got on the gas.

 

[HISSIN50]

bad engine ground will probably make the car run like crap and buck in higher rpm. I forgot to tighten mine and the car started and idled fine, then got all messed up when I got on the gas.

The starter is the largest electrical-draw item on the car. In your case, the ground contacts were probably ok until the motor really started to sing, in which case continuity became intermittant.