End of my wits here

[mustang_montana]

my 84 turbo is a wiring nightmare. i made a previous thread about this but no one said anything so ill try again...there is now power comming from the red wire that goes to the fuel pump relay, nor is there any from the brown wire. i believe both of these go to the eec power relay, but that checks out as having power. what else could short these two wires? specifically where or what could break the connection? ive replaced every fuse link i came across, checked all grounds, replaced the fuel pump relay and eec relay.

 

[d.s.s 306x]

I'ts most likely the internal ground in the comp. same thing happened to me in a 90 lx. just bypassed it with a lighted rocker switch and called it done.it's just what i did so take it for what it is. good luck

 

[mustang_montana]

thats what im thinking about now cause the eec relay isnt clicking on even though i replaced it and its getting power. the ground that goes from the computer is good though, i dont see how it could be damage inside but i guess a different computer is probably next.

 

[jrichker]

Have you seen this?

Some of the grounds are very lightly drawn, so look closely at some of the wires in the fuel pump circuit that don't seem to go anywhere.

EDIT: What I just noticed was that the ground control circuit for the fuel pump relay was missing. On 5.0's it is pin 22, so it migt be the same for your car.


AutoZone wiring diagrams

http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp for 79-88 model Mustangs

http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp for 89-93 model Mustangs

http://www.autozone.com/servlet/UiB..._us/0900823d/80/1d/db/3c/0900823d801ddb3c.jsp for 94-98 model Mustangs

 

[Saleen0679]

I mentioned that Autozone diagram a few days ago. Note the incomplete fuel pump relay circuit.

 

[oldschool88vert]

i had to do the same thing....

in my third mustang. just wired up a switch. just had to make sure i turned it off.

 

[mustang_montana]

in my third mustang. just wired up a switch. just had to make sure i turned it off.

whered you wire the switch too? im thinking my problem is the computer, cause its beat to ****. continuity checks out on every possible wire, so the ground which is brown for mine (the one that leads to pin 22) maybe bad i think. see the eec power relay isnt clicking on and so the fuel pump relay isnt so the fp isnt. i really just gotta get that eec relay clicking on, and make sure the fp relay ground is fine. i think that should get her running. any other advice on how to get the eec working again? replaced the relay and its getting power to the plug, would a bad computer(a shorted ground inside) cause all these relay issues?

 

[rd]

Off the wall item here, but does't the EEC and, or, the fuel pump relay get switched by the IRCM or CCRM on the 4 cyl cars? Could that be it?

 

[mustang_montana]

i have no idea, but i opened up my computer and there is some real obvious damage in one section. its all burnt up with char covering the circuits.

 

[mustang_montana]

gonna have a new computer by thursday, until then im still open for suggestion. like i said continuity is fine, and everything seems to be in order with exception to the charred up computer. any other imput as to whether a burnt computer board would effect the computer ground?