god i am just sick about this! i tried to see if any codes were stored on ecm and jumped the wire and so on,well i hooked it backwards ..positive wire where you jump to sig return and after that no start....smelled very faint burn smell but maybe that was in my mind,hot wire wasnt hot.anyway where do i begin now?how do i determine if ecm is bad or maybe a blown relay or something?anyone with an idea?its a 92 f150 kingcab with 5.0...just to note the truck sat for an hour and actually ran but wouldnt idle...i had to hold my foot on the gas,tried to hook up self test again becouse this time cel was on,,well self test did not work,tried to let it sit,unhooked battery etc and now absolutely no start,yes i can hear fuel pumps prime up

 

Ecm fuse

 

I doubt if you are the inventor of this mistake, I am surprised tho that Ford doesn't or didn't have a diode in the circuit to prevent this from happening. Hang in there, the right help will respond, be patient and good luck.

 

looked for a ecm fuse but did not find one that said ecm specificly,none in the cab fuse compartment then looked under the hood with the large fuses and a couple of relays,even switched the two relays and no good so put them back as they were.so i am hanging in there and waitingthanx for the help guyz

 

so can you pull any codes from the ecm as it sits now? if the light stays on thru the keor test and does not blink at all it may be in fail safe mode or just gone if its crispy fried it shouldn't even kick on the fuel pumps.

 

no it will not even go into self test mode,yes the light just stays on...what is fail safe mode?can i fix that?

 

no you can not fix the failsafe mode and it sounds like it is just gone if the only thing turning on is the basic electricals you might need a new ecu

 

wheres the best place to get one?junk yard?online?how difficult would it be to get one in a junkyard?i mean it has to have the 5.0 and between the years 92 to 96?

 

Best way to know if there's one in a junk yard, call or go find out. Every junk yard is different. I'd call around and look online.

 

buy a new one from audvanced auto they are 100 bucks new and have a 1 year warranty i replaced mine with one of them and it works great junkyard ones are hard to find for the exact truck and have no warranty its best to save your self some time and money by getting one brand new and its right for your truck.