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  1. #1

    Default Mustang SVO dies while running

    Hello , before I go into the issue with my SVO let me give a little history on the car to hopefully give a little insight to the issue.
    I bought the car from the original owner who had just about every receipt for repairs on the car. The car is completely original and she, the previous owner, tried to use all Ford parts. The last time there was any receipt for repair was in 98, The brother installed a new fuel tank, both fuel pumps and had the head rebuilt. All of that is good and have no issues with the motor, I did a compression test and all cylinders read 150 psi. I also checked the fuel pressure and is also good, 45 psi and up when cranked.
    Now, here is what I've done to the vehicle in the two months since I bought the car. I replaced the PCV valve (it smoked bad), I replaced the ignition control module, it wouldn't start at one time and no power going to the module. The ignition switch, the one on the steering column,Motorcraft part from Autozone, and several wires from the harness that runs from the firewall on the driver side to the control module and coil, the insulation was literally crumbling off the wires. I thought about checking for codes but the harness wires insulation is so damaged and corroded that I don't think I would get a good reading anyway so no go there.
    Now my issue, the car starts fine,every time, idles well but when I start to drive it and the car is running, it will die randomly, with no warning or hesitation, just dies, no rpms but everything else is on like the radio and any other accessories that might be on. I have to come to a complete stop, wait a few seconds, and then turn on the car at which point the car will turn on and run, like nothing happened.It does it randomly and not necessarily when its warm. I have only driven the car in my neighborhood for fear that it might break down or even worse, turn off when I'm on the highway in traffic(Austin traffic is horrible)Does anyone have any ideas as to where to begin to look or troubleshoot? maybe even test the items I installed? I wouldn't rule out a bad switch or module. I know there's experience here on this forum with this issue and I've tried searching for an issue like mine in the archives but no such luck. Any help is appreciated.

  2. #2



    Anyone not have any input on this issue?

  3. #3
    Moderator wraithracing's Avatar
    Join Date
    Jun 2010
    Grand Junction, CO/RR TX


    You don't state what year model SVO, but based upon the crumbing wiring I am going to guess a 1984 model. If so that year model for all Foxes had wiring issues related to the insulation deteriorating over time.

    Even if the SVO is not a 1984, my guess is the wiring is most likely your issue. My thought is that you have a power wire that is grounding out or a ground wire that is loosing contact when the vehicle is in motion. That kills the power to the engine/ECU and the vehicle dies, but everything else stays powered. Then everything resets and the vehicle starts up again.

    I would look at the wiring with any missing insulation or crumbling insulation, especially going to the engine and ECU. Repair as necessary and see if that corrects the problem. Good Luck!

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Ongoing RestoModification
    1984 SVO Awaiting Restoration
    1986 GT Wrecked by PO, but still want to save!

    Current Capris:
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    1982 Capri RS 5.0/4spd T-top Full Restoration Underway
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  4. #4
    FEP Member
    Join Date
    Oct 2017
    south-central WY


    If I were you, I'd check for codes. Costs nothing but time and might give a clue about the problem. I would try to clean any obvious corrosion and try to separate/temporarily insulate any wires that might contact any other metal. Temporary insulation could be anything non-conductive, cloth, plastic straws, electrical tape, duct tape, even masking tape. The phone company used lead-sheathed underground cables with paper insulation between wires for decades, with services using ~100 volts.

    What happens if you try to restart the engine while the car is still moving? Do you have to stop and wait before it will restart?
    Last edited by darkd0r; 09-15-2019 at 01:48 AM.

  5. #5


    I guess posting the year of the vehicle would've helped huh!,yes it's an 84.
    Darkdor,I have to come to a complete stop before it will turn on again.ill check and replace some bare wires and test drive again and I'll post what I find,oh and check for codes after I replace the test connector harness.

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