85 cherokee with no fire

[K5MAN]

my son has a 85 cherokee with a 2.5 4 cylinder we just rebuilt the engine and now it won't fire but once when you let the switch go any ideas.

 

[hadfield4wd]

so it runs when on start, but when you allow the switch to go back it turns off?

 

[K5MAN]

no the engine turns over and no spark from coil until you let the switch to go back and then it will spark 1 time

 

[madmax1124]

check the ignition switch down on the steering column sounds like it went bad.it's not making contact in start position.

 

[K5MAN]

ok i'll check that next

 

[Ridgerunner]

Sounds like you are losing your 12v to the coil when your key switch is in the crank position. Make sure that if this is something that is wired differently from Stock that the wire is hot at alltimes when the key is in any posistion except off.

 

[K5MAN]

with the switch on i have 6.5 volts and while cranking i have 10.5 volts to the coil

 

[K5MAN]

Ok I have checked the switch and it checks good replaced the coil replaced the pick up in the dist. and had the ignition mod checked and it checks good but still no fire while cranking and one spark when the switch returns to the on position.
This thing is driving me crazy!!!!
Anyone had this happen before????? if so what was it HELP PLEASE!!!!!!!

 

[K5MAN]

Ok I got it going finally i bypassed the ECM and boom there is fire so we went with it go figure