SHO experts? I need help with my 93 SHO

[quick35th]

So I recently aquired a '93 SHO 5spd with 160k on the clock. I knew going into it that it has some electrical problems and I suck at fixing electrical issues.

 

Anyways the car would randomly stumble/buck in low gears, mostly on right turns. I ended up killing the CCRM and then I lost power to the fuel pump. Long story short I hard wired the fuel pump to a switch on the dash because I figured I have a short somewhere in the wiring harness.

 

So now the car does run BUT its constantly popping the 30amp EEC relay fuse under the hood. It will run and drive for maybe 20-40 minutes then die because it blows the fuse. Also after it tried to over heat I found the 50amp fuse for the cooling fan was blown as well

 

Why am I blowing all these fuses? Any ideas? I do know the previous owner put a junkyard alternator in it because he thought the old one was going bad. Maybe the voltage regulator is bad and its putting out to many amps causing an over load. Idk its just a thought.

 

Someone please help me before I go insane.

 

Shane

[Guest Removed]

do you have test equipment like a DVOM?

[19TbirdSC91]

do you have test equipment like a DVOM?

 

I've been helping grandma's boy out with this. What is a DVOM?

 

Sean

[Guest Removed]

I've been helping grandma's boy out with this. What is a DVOM?

 

Sean

 

well theres the issue..grandmas boy, and you dont even know what a dvom is..

 

Digital Volt Ohm Meter

 

 

a good one..not harbor freight crap either

[6 Speed S4]

Digital multimeter to check voltages, amperage, and ohms.

 

 

EDIT: Rob beat me to it haha

[quick35th]

Sigh, I don't even know the first place to check for voltage, amperage, resistance and so forth and what everything means. Electricity is not my cup of tea.

 

I do however have a barrowed Fluke DVOM from Ryan. So if I knew what I was doing I could figure things out.

 

Shane

[Guest Removed]

well, i would say i can give you the diagrams, but without under standing the system and how it works, they would be useless to you..i can how ever fix it for you...but that would be on you. these types of issues are rather hard to fix via the internet.

 

but IMO, it sounds like something is shorted out or has lost it ground, causing it to draw too many amps. kind of been my forte if you will.

[Ryan218]

ill be over tomm after class before i got to go to work. you have short somewhere in the fuel pumps wiring is my guess thats causing to to keep blowing the EEC relay and CCRM's maybe a bad ground. i hate wiring with a passion. like i told you fromt he start. START tracing the wires. look for burned up wires. pinched, exposed. it does it around hard right hand turns is when it dies. something in the wirring harness is moving around and casuing this. need to gut the interior and start tracing wires.

[19TbirdSC91]

ill be over tomm after class before i got to go to work. you have short somewhere in the fuel pumps wiring is my guess thats causing to to keep blowing the EEC relay and CCRM's maybe a bad ground. i hate wiring with a passion. like i told you fromt he start. START tracing the wires. look for burned up wires. pinched, exposed. it does it around hard right hand turns is when it dies. something in the wirring harness is moving around and casuing this. need to gut the interior and start tracing wires.

 

Actually today, it did it on a left turn as well when Shane (grandma's boy) wasn't in the car. It also did it going straight, so to me, the right thing is irrelevant.

 

Sean

[Guest Removed]

ill be over tomm after class before i got to go to work. you have short somewhere in the fuel pumps wiring is my guess thats causing to to keep blowing the EEC relay and CCRM's maybe a bad ground. i hate wiring with a passion. like i told you fromt he start. START tracing the wires. look for burned up wires. pinched, exposed. it does it around hard right hand turns is when it dies. something in the wirring harness is moving around and casuing this. need to gut the interior and start tracing wires.

 

maybe you should make sure theres gas in it :gtfo:

 

 

and tracing each wire is a last resort type thing..not the first thing you do...

[19TbirdSC91]

There is definetly enough gas in it, we witnessed that when we put the new fuel pump in it.

[Guest Removed]

There is definetly enough gas in it, we witnessed that when we put the new fuel pump in it.

 

when did this happen? and why?

 

 

more of the story might help me help you... give me more input to work with...

[quick35th]

ill be over tomm after class before i got to go to work. you have short somewhere in the fuel pumps wiring is my guess thats causing to to keep blowing the EEC relay and CCRM's maybe a bad ground. i hate wiring with a passion. like i told you fromt he start. START tracing the wires. look for burned up wires. pinched, exposed. it does it around hard right hand turns is when it dies. something in the wirring harness is moving around and casuing this. need to gut the interior and start tracing wires.

 

Ryan,

 

You need to remember that we completely bypassed the factory power wire going to the fuel pump coming out of the CCRM when I hard wired the fuel pump to the switch on the dash. So if somewhere in the line there is a bad piece of wire that's shorted out its not getting power anymore at this point.

 

Also the CCRM that I got out of the '89 SHO in the junkyard is still good and has not blown up yet. Only thing that's blowing up is the 30amp EEC relay fuse and now the 50amp cooling fan relay.

 

I took the fuel pump power and fuel pump power B+ pins out of the connector for the CCRM in hope to prevent any back feeding. After looking at the EEC-IV wiring diagrams on Michele on demand and on my Ford service manuals on cd the yellow wire fuel pump power B+ pin 12 is tied into the 30amp EEC relay which is why I took that pin out.

 

I wish I could figure out where the grounds are all located at so I could just look them over one at a time.

 

Shane

[quick35th]

when did this happen? and why?

 

 

more of the story might help me help you... give me more input to work with...

 

I replaced the fuel pump before screwing with everything else because I was not getting fuel pressure at the rail and the pump was not cycling when the ignition was turned on. Typical symptons of a dead pump and since I had a spare laying around I said what the hell.

 

Shane

[19TbirdSC91]

we had the alternator tested twice today, both places said that it was all good. so now we just need to find out where all the grounds are on this thing.

[Guest Removed]

try the fan controller that mounts to the core support...those are known problems on these cars...

 

remove the stock fuel fump relay, it the stock wiring is by passed, then that relay should be pulled, so it not sending power to it still and causing a short.