Please read before i set fire to my sho! (long)

[shoftw]

ahhh.... where to begin, never really had any problems with my v8 sho till now about 3 months ago went out side to dead car check for fuel pressure and did not have any. I'd been having low fuel pressure for a while so just thought the fuel pump was dead so i replace it still no dice but i did find out why i had low fuel pressure there was a hole in the fuel line in the tank.

After doing some checking around found the eec ign fuse blown so i replace it and it poped as soon as i turned the key. Everybody told me there was a short somewhere but after checking everything and getting no where i let the car sit for a month and a half one day i tried to start and it did.

it ran for 3 days on the 3rd day the fuse poped on first 30 seconds on startup.This time i notice that the check engine light stopped working when u have the ignition in the on postion and thought the light had went out but once the car would run it would work again.

After letting it sit for a long time i took the fuse panel apart looked fine put back together and it started this time it work for 4 days did the same thing in the morning as i was leaving out of drive way.


This time i took apart almost all the wiring in the car to find nothing ( that was a pain in the a#$) the only thing that looks weird is the ground wires for the pcm are not covered just there exposed but it looks like thats how it came from factory so i don't know.

This time once i put it back together i ran for a whole month even went on a 1000 mile trip then did the same thing in the morning while backing up. To make a long story short this is what i know fuse will pop with ccrm and pcm disconnected(fuel pump to) if i pull the first ign fuse in the engine compartment it wont blow and as of yesterday if i cycle the ignition a hole bunch of times the check engine light will come back on in the on postion and the car will run.

I replaced the ignition switch but it still does it. When i do this i have to hot wire the fuse or else it pop the fuse( i know i know) also when i hot wire it it has a big current draw when i turn the ignition on the lights go almost dead.

So has anyone ever had this problem before? Im at the point where i want to burn this car lol. Sorry for the long post and any help would be greatly appreciated.

 

[93rev2sev]

I'd be swapping in a new PCM.

 

[LJRuddy]

An erratic or non functioning check engine light is 99% a bad PCM.

 

[shoftw]

I pretty sure its not the pcm because it still does it with pcm disconnected witch pretty much tell you its somewhere before it. But i don't know at this point.

 

[frosho]

The PCM is the computer, so the car is obviously not going to start with it disconnected. See if you can get a known good one to try.

 

[E1 v2]

You probably have a coil wire shorting out on a valve cover. Insulate all your coils wires and see what happens.
I'm in the communist regime of Illinois too(Lombard), if you can get the car over to me maybe I can help you some more if the insulating doesn't fix your problem.

 

[ThatShoGuy]

The PCM is the computer, so the car is obviously not going to start with it disconnected. See if you can get a known good one to try.

he said while testing it he had the pcm unhooked and the fuse still popped.

if you think its before the pcm i would ohm all the wiring and see if you find a short in a power wire where there shouldn't be a ground

 

[shoftw]

I've already insulated the front and back coil wires with aluminum foil. I kinda think it's not a short because it only does it in the morning right on start up and now i can just cycle the key a few times and it will start right up. Do anybody know where i can get a wiring diagram for this car at? Also does anybody know what the 3 relays under the drive side by gas pedal are for? Thanks!

 

[shoftw]

You probably have a coil wire shorting out on a valve cover. Insulate all your coils wires and see what happens.
I'm in the communist regime of Illinois too(Lombard), if you can get the car over to me maybe I can help you some more if the insulating doesn't fix your problem.

Might have to take you up on that offer.

 

[tardboy21]

To make a long story short this is what i know fuse will pop with ccrm and pcm disconnected(fuel pump to) if i pull the first ign fuse in the engine compartment it wont blow and as of yesterday if i cycle the ignition a hole bunch of times the check engine light will come back on in the on postion and the car will run.

Could you provide some clarification here? Which fuse is the "first" one, which fuse # is blowing? Is that the same one you removed and cycled the ignition to start or a different one?
Want to help just want to make sure I'm crystal clear on what you are doing first.

 

[shoftw]

Could you provide some clarification here? Which fuse is the "first" one, which fuse # is blowing? Is that the same one you removed and cycled the ignition to start or a different one?
Want to help just want to make sure I'm crystal clear on what you are doing first.

The fuse that keeps blowing is the 20amp eec ign fuse inside the car. If i pull the 40 amp ign fuse in the engine compartment( first 40 amp ign from the left,there are 2 of them) it wont do it. Also when i hot wire the 20amp fuse if i leave the ignition on it will blow the 40amp fuse in the engine compartment. Once the fuse pops 20 amp eec i just hot wire it and keep cycling the ign switch and the cel will come on and the current draw will stop and car will start.


Thats why i think its a bad component something to do with the ignition system maybe? Does anybody know what the 3 relays on the drivers side by the gas pedal are for? Also a week before it ever stated doing this the cel stopped working when you turn the ign to the on position. I thought the light had blown out but the i tried to scan for any codes and all i would get is error and if it makes any difference i do have a code for secondary air injection incorrect flow but have unplugged the pump and it hasn't came on yet.

 

[ThatShoGuy]

you just might need a new pcm.. other then going thru the wires im not sure where to tell you to start..

i think those fuse's are related with the turn signals and lights.. but dont hold me to it.

 

[tardboy21]

If I am reading my manual correctly, on the one side of the 20A fuse you got connections to the CCRM, 8 coils and 2 radio noise capacitors, and PATS system.

Power to the 20A fuse comes down form the 40A fuse (#3) in the engine compartment fuse/relay box. The 40A fuse supplies power to quite a few other things, all are fused (5A, 5A, and a 10A). The one other thing to look at is that in the SHO model the Starter Relay pulls power off that line as well.

 

[shoftw]

If I am reading my manual correctly, on the one side of the 20A fuse you got connections to the CCRM, 8 coils and 2 radio noise capacitors, and PATS system.

Power to the 20A fuse comes down form the 40A fuse (#3) in the engine compartment fuse/relay box. The 40A fuse supplies power to quite a few other things, all are fused (5A, 5A, and a 10A). The one other thing to look at is that in the SHO model the Starter Relay pulls power off that line as well.

^Thanks, i really think its a bad relay too but i was told the starter relay is in the ccrm and it still blows with that unplugged. Are the 3 relays on the drivers side right above the gas pedal have any thing to do with the 20 eec or 40amp fuse? Also do you know what they are for? :thankyou: you have been very helpful.

 

[E1 v2]

Please.

Humor me. Aluminum is a GREAT conductor of electricity, not an insulator. Every time I've ever seen a problem with fuse #10 (The 20 amp PCM fuse I believe you keep popping) it has been a coil wire grounding on a valve cover.
Wrapping a wire with damaged insulation with aluminum foil is only going to expand your potential conductive surface area.
Take the highly conductive aluminum OFF the wiring loom and coil wires and give the little stub end branches that go to each coil a good wrap in electrical tape from the plug back to the main loom lines, especially on the rear wiring loom.
Put it back together and give it a try.

 

[shoftw]

Please.

Humor me. Aluminum is a GREAT conductor of electricity, not an insulator. Every time I've ever seen a problem with fuse #10 (The 20 amp PCM fuse I believe you keep popping) it has been a coil wire grounding on a valve cover.
Wrapping a wire with damaged insulation with aluminum foil is only going to expand your potential conductive surface area.
Take the highly conductive aluminum OFF the wiring loom and coil wires and give the little stub end branches that go to each coil a good wrap in electrical tape from the plug back to the main loom lines, especially on the rear wiring loom.
Put it back together and give it a try.

Ok will give that a try but if that is my problem it would have to be the rear because i went threw all the wires on the front valve cover and none of those where burnt. I did take a good look at the rear to but i did not cut into the rear harness but it was in very good condition and the rear coil wires from where the coil plugs in to the wire harness did not even touch the valve cover.Thanks!

 

[shoftw]

So i had no other choice but to take this car for thanksgiving drive 2 st louis and to take a friend to pick up a v6 sho. Went 1300 miles thanksgiving weekend with no problem then yesterday had to leave quickly and did not let the car warm up and it did the same thing again about 2 blocks down the street.

After cycling the key a lot and blowing up 2 40 amp fuse in the engine caparment ( i have the 20amp fuse wired) i finally got it to start. After getting 2 blocks it did the same thing again and after cycling the key again it started right up and acted like nothing was wrong. After getting home i decided to scan the ses light and got a pending p1414 manufacturer auxiliary controls.

Ever since last time about 3 weeks ago ive had tha sai pump unplugged so this might be why im getting this code now but when i looked up what this code means and i get to different answers 1 says p1414 secondary air injection monitor circuit high voltage service manual says air pump commanded off but pcm indicates electric air pump is on but this can't be because i have the pump unplugged.


2 says The electric air pump draws high current and must be energized through a separate relay. Both the primary and
secondary circuits are checked for opens and shorts. First, the output driver within the PCM (primary circuit) is
checked for circuit continuity (P0412). This circuit energizes the relay and the control valve(s). Next, a feedback
circuit from the secondary side of the relay to the PCM is used to check secondary circuit continuity (P1413,
P1414).
AIR Monitor Operation:


But i think this might be my problem and that's why the fuse only pops when the car is first started up when the sai system would be on. My pump works ive checked but i can't find the relay or what ever its called. Does anybody have a picture? I also read on a mustang forum a guy complaining about why would ford put an electric pump there where it gets wet and will short out so i defiantly think this may be my problem.:thankyou: also one of the times after i got the car started i pushed on the gas and the abs light came on then went back off weird.

 

[SHOZ123]

The solid state relay is shorted. Just pull the fuse. The relay is mounted on the bracket the SAI is on and the SAI plugs directly into the relay.

I have a couple of complete SAI pumps and relays if you are interested.

You could rewire the stupid thing with a normal 40A relay or get a tune that shuts it off.

 

[shoftw]

What fuse am i suppose to pull? Thanks

 

[SHOZ123]

I believe it is called the Thermactor Pump, is 30A and located under the hood.