NEED HELP ASAP - '95 Cougar

cbeeler7709cbeeler7709 Member Posts: 3
edited December 2014 in Mercury
Have a 1995 Mercury Cougar 4.6 V8 when you start the car it runs speedometer to 120 then when it drops back down to 0 the car dies. It ran fine for two days. What would be causing this please anyone

Comments

  • cbeeler7709cbeeler7709 Member Posts: 3
    Please if anyone has any ideas the car is broke down right now really need help
  • thecardoc3thecardoc3 Member Posts: 5,462
    The best action is to diagnose exactly what it is doing right now. Does it run at all? Is it a cranks but won't start, or is it a won't start no-crank?

    The speedometer issue "suggests" a lot of electrical noise to the point that the instrument cluster reacted like it had a valid vehicle speed signal. With a lot of cars the manufacturers have a speed limiting function engineered into the system and if the car really thought it that was going 120mph it is entirely plausible that the computer would shut the engine down.

    So right back to the fact that the car won't run. For the moment, disconnect the alternator and lets see if you can get it started and keep it running even if you have to jump start it with another car.
    If it starts and runs and the speedometer is working normally again, then reconnect the alternator and watch what happens. If the symptoms return we are going to be looking for excessive resistance in the charging circuit or an issue with the alternator itself.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    No way to guess on this. By all means check your battery cables and clean and tighten them, and run a voltage test on your car's charging system.
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