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Ign coil conector shorted on chasis

2K views 11 replies 2 participants last post by  wbrockstar 
#1 ·
So im running full msd digital box , where u plug the wires to the conector for the coil it touched the chasis turned my car off , now it doesnt prime when key on , no spark ethier , all my fuses look good i replaced my ign switch , tfi module looked crispy replaced that , changed starter solonoid , i was thinking the fuel pump relay , i put a + and - and you can hear it click , i check voltage at the pump harness one pin is giving 2.5v other is 7.5v with key on
 
#2 · (Edited)
Locate the diagnostic test port,shown in the diagram below.Turn the key on,connect one end of a jumper wire to a good ground then touch the other end to the fuel pump trigger terminal on the diagnostic port.The fuel pump should run.If it doesnt,check the inertia switch,in the hatch area,has it been tripped??Try to push the red button down.If the button doesnt move,it isnt tripped.Youll hear it click if it is tripped.If was tripped,turn the key on and try to trigger the fuel pump again.If it still doesnt run,youll need to do further testing.
I would begin testing some of the fusible links with a multimeter.They all run off of the starter solenoid.Test the solenoid side of each link to make sure it has 12 volts.Youll have to pierce the wire insulation with the meter lead or remove a tiny bit of insulation (( be sure to wrap electrical tape around each wire when youre done testing.Actually the best thing to use on something like that would be liquid tape.You just dip the brush in the liquid & cover the bare wire spot with it and once it dries it looks/feels just like tape.Autozone & other parts stores sell it,it comes in a small can in the rtv isle of the store)) If all of the links show 12 volts,test each one on the firewall side of the link.If any link shows 0 volts,on the firewall side,the link is burnt in two & needs replacement.Test every fusible link that feeds the eec relay,fuel pump relay & the ignition switch,by using the diagram in the link below.Youve most likely got one or more links burnt,due to the spike caused by the wire to chassis contact.The ignition switch provides ignition on power to pretty much everything(ignition,fuel pump,ecm)so if its link is blown,none of those systems will work.Make sure you test the links that feed the ignition switch first,since the switch supplies power to all of the other components.The ignition switch provides power to the eec relay and the relay powers ecm,injectors,solenoids,fuel pump relay,etc. so if the eec relay doesnt energize,due to a blown link or a bad relay,none of those components will work.
If you turn the key on,connect a meter to one of the injector red wire terminals & a good ground,the meter should read 12 volts.If not,the eec relay is suspect,a fusible link is blown or the ignition switch is suspect.If the injector wire has 12 volts,the fuel pump relay is the next thing to check.
Once you view the diagram below, finding the links & understanding the circuits will be much easier.All of the fusible links running off the starter relay are Hot At All Times,so in otherwords the key doesnt have to be on in order for them to be hot.The 20ga link,between the ignition switch & the clutch safety/neutral safety switch,is only hot when the key is on.Ive never looked for this link before,but the diagram shows it being somewhere between the ignition switch & the clutch safety switch.It might/might not be located somewhere on the steering column or it might be in the wiring under the dash.The safety switch is at the clutch pedal.


http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
 

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#3 ·
I dont have any current going to the eec , i checked all the wires with key on 0 volts , fuse 18 has no power ethier , from the starter solonoid i checked the 4 wires with the fuse links they all have 11.5v from one end to the other , those would be the fuse links right ?
 
#5 ·
Turn the key on and test the red/green coil wire for voltage.It should have 12 volts.If it doesnt,the ignition switch you bought is bad or the fusible link is bad.If you dont get power at the coil,the eec relay wont provide power to everything it feeds(fuel pump relay,ecm,etc)because the low current side of the relay gets its power through that same red/green wire in order to close the contacts on the high current side of the eec relay.That would explain why the ecm,eec relay,injectors & everything else isnt getting power.You also said fuse #18 isnt getting power.If you look at the wiring diagram I posted,see how fuse #18 is powered by the ignition switch?? Power runs from the ignition switch towards the eec relay on the red/green wire,so fuse#18 should power up if that terminal on the ignition switch is sending power out of it.If the 20ga fusible link were blown,fuse #18 should still get power,but everything from the link to the eec relay wouldn't.
Test the yellow wire at the ignition switch to see if its got 12 volts.If it doesnt,the 18ga fusible link is blown on the yellow wire between the solenoid & the ignition switch or the yellow or brown wire has an open between those same points.
If the yellow wire does have 12 volts at the ignition switch,turn the key on & test the red/green wire at the ignition switch.If it doesnt have 12 volts,the ignition switch is bad.If it does have 12 volts,but the red/green wire at the coil doesnt have 12 volts,the 20ga fusible link is blown,the red/green wire is open between those same points or the clutch safety switch is bad.Going by the diagram,the 20ga link should be blue & it should be on the harness somewhere between the switch & the clutch safety switch.
BTW-what year car are you working on??


http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
 
#10 ·
I think i found the broken link it was hidden there are 3 blue fuse links 20g near the wiper motor , the diagram shows 1 , it was funny cuz one of the ends felt real soft and rubbery i pulled it and it snaped it has 12v with key on , wire color is red and light green or pink w.e it is. , ill keep u posted
 
#12 ·
Thats great news man.
Electrical gremlins are common on the Foxbody when they reach 20+ years old.
The following list is common problem areas electrical in nature.

1) 10 pin connecters
Location=behind upper intake
2) Wire splice at tps & evp sensor
Location=where evp/tps wires meet behind egr valve/upper intake
3) EEC ground wire & black tubular connecter
Location=driver fender apron to the right of the starter solenoid.Connecter is 6" from the forked off wire



Fuel Injection Technical Library » 10-pin Connector Fix
 

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