Running on 7?

[jrichker]

The red wire on the injectors is power from the EEC relay circuit. It is always
hot any time the switch is in the Run position. The computer switches the
other side of the injector to ground to comlpete the circuit and fire the
injector.

The wiring for the injectors may have some bare spots in it causing the
injector to computer control wire to ground out. This would cause the
injector to remain on anytime the key was in the Run position. Remove the
injector wiring connectors from the injector. Note that each injector has one
red wire for power and a non red wire (wire some color other than red) for
computer controlled ground. With the key off, disconnect the computer
connector from the computer. Use an Ohmmeter between the non red wire
and ground. You should see more than 100000 (100K) ohms resistance.


See the following website for some help from Tmoss (diagram designer) &
Stang&2Birds (website host) for help wiring http://www.veryuseful.com/mustang/tech/engine/

Diagram courtesy of Tmoss & Stang&2birds

Using the above diagram, check the resistance between the injector and the
computer. Clean and check the 10 pin connectors since they are a potential
trouble source. Any resistance greater than 1.5 ohm between the injector to
computer wire and the matching pin on the computer connector is a problem.

See http://fordfuelinjection.com/?p=6 for more help

 

[Synned]

Thanks for the diagrams, are they the same for SN95's as well?
If, in fact, the injector was always on wouldn't it just dump gas? Would the spark plug be soaked?

How about if I just run a new non-red wire to inj 2 from the computer? I dont understand what can be causing this, I hope the computer isn't bad.

Now I'm a little confused, does the grounding wire go to the CCRM or straight to the PCM?

 

[jrichker]

Thanks for the diagrams, are they the same for SN95's as well?
If, in fact, the injector was always on wouldn't it just dump gas? Would the spark plug be soaked?

How about if I just run a new non-red wire to inj 2 from the computer? I dont understand what can be causing this, I hope the computer isn't bad.

Now I'm a little confused, does the grounding wire go to the CCRM or straight to the PCM?

Use the meter you have to check the wiring per the instructions in my last post. Do not run any other wires or change any of the wiring. Verify the wiring before you do anything else.

The following diagram is for 94-95 5.0 Mustangs.

The 10 pin connectors are the same for 86-95 Mustangs.

 

[1988WHTGT]

Mine was doing the same thing a couple days ago. Found out #3 wasn't firing. Put Plugs, Cap and Rotor on it and its fine.

 

[Synned]

yea, welll I already figured out its something with the #2 injector, I think its the ground pulse wiring from the computer.

 

[Synned]

I'm just sitting at work wondering...is it possible the computer went bad?
Just want to know if its a possiblity

 

[jrichker]

I'm just sitting at work wondering...is it possible the computer went bad?
Just want to know if its a possiblity

Yes, but don't rush out and buy a computer until you have carefully checked & tested the wiring. Doing 15 minutes of testing with a multimeter or DVM can help you find the problem and fix the right thing rather than guessing at it.

 

[Synned]

Yes, but don't rush out and buy a computer until you have carefully checked & tested the wiring. Doing 15 minutes of testing with a multimeter or DVM can help you find the problem and fix the right thing rather than guessing at it.

Yeah, I was just wondering...

 

[Synned]

Yay! Figured it out...its weird though.
I ewnt to my buddies house who has a noid light and we were checking for pulse on #2. It worked, then it didnt, then it did, then it didnt.
We couldnt figure it out for about 10 minutes and then we saw the injector harness was wrapped around the bundle of wires...we unwrapped it around this thing and now it pulses all the time. I guess there is a break in the wire and when it gets pulled it disconnects.
I have no clue HOW this happened, I haven't ever touched the freakin injectors...im just glad I figured it out.

Thanks guys

 

[HISSIN50]

Nicely done with the wiggle testing. I might do it again to make sure the wire isnt going to 'open' again (in its new configuration).

Congrats.

 

[jrichker]

Yay! Figured it out...its weird though.
I ewnt to my buddies house who has a noid light and we were checking for pulse on #2. It worked, then it didnt, then it did, then it didnt.
We couldnt figure it out for about 10 minutes and then we saw the injector harness was wrapped around the bundle of wires...we unwrapped it around this thing and now it pulses all the time. I guess there is a break in the wire and when it gets pulled it disconnects.
I have no clue HOW this happened, I haven't ever touched the freakin injectors...im just glad I figured it out.

Thanks guys

Now you know why I keep pushing people to do the diagnostic tests. You have saved a bunch of money by doing your homework and not panicing ang thowing parts at it.

Good job.

 

[Synned]

Yup, thanks so much guys for your awesome help as always!

Im ordering my midpipe tonight weeeeee

 

[Synned]

Okay so I have been down the shore this whole weekend...and it was perfect all the way down (100+ miles) and then the 2nd night I start it up and bam running back on 7. I started to unwrap the bundle of wires next to the fuel rail and got about 6" of the white wire exposed, and it did look like it was pinched.
Its the strangest thing...this problem is so random it seems to choose when it wants to work and when it wants to do it. Ill start the car up and it will be perfect, later that day it will feel like **** and then maybe fix itself.
On the way home from the shore it was fine for 70 miles then it happened for the rest of the way home.
Wiggling the wire doesnt help anything. WHen I got home I cut the wire from the harness about 4" back where the pinches were and replaced it with wire. Started it up and there was still a misfire. I got so mad...lol...but tomorrow I am going to runa wire directly from the computer to the injector and see if it goes away.

 

[Synned]

So does anyone have any suggestions?
I think I'm also gonna borrow 12v from another injector because that could be a problem too.

 

[jrichker]

Clean and check the 10 pin connectors since they are a potential
trouble source. Any resistance greater than 1 ohm between the injector to
computer wire and the matching pin on the computer connector is a problem.

See http://fordfuelinjection.com/?p=6 for more help

 

[Synned]

I don't even see these connectors on my car. It's a 95...and by the firewall I see a 10 pin connecter its black...but I don't see the white one. I'll look again when I go home.
What exactly is the purpose of these connectors?

 

[jrichker]

I don't even see these connectors on my car. It's a 95...and by the firewall I see a 10 pin connecter its black...but I don't see the white one. I'll look again when I go home.
What exactly is the purpose of these connectors?

They allow you to remove the engine without disconnecting every wire on it one at a time.

 

[Synned]

Well I just measured resistance and it is zero, but the problem is not occuring right now. I'm going to unhook the multimeter from one side and drive around till the problem happens, then measure my resistance. I really hope I'm losing resistance, or else I guess its a damn computer problem. I just don't get how the wire doesnt move and it loses all connection from just driving around.

BTW: This is the only connector I see, I sprayed electric cleaner in it.

The thing is I don't think its the computer because moving the harness fixed the initial problem that I could never get running right. Now it's just intermittant.

 

[LEE93COBRA]

Have you considered replacing the wire. Seems to me that would be logical

 

[Synned]

Yeah, I just don't feel like running a wire all the way back inside yet untill I'm sure its the problem...I want it to be clean too. If theres a part of the wire I can cut off 6" and replace that would be a lot better.