Turn Key And Nothing

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by cnorman31, Aug 31, 2017.

  1. Ok guys so here is what is going on. I just got my computer back from ECU exchange because my fuel pump would not stop priming. I hooked up the computer and it seems to be working correctly now because the fuel pump not stop after a couple secs. But now i have another problem. When i turn the key, nothing. Just a click and the light go out. I have to unhook the battery to reset, try again...same thing. I tried jumping from the sil
     
  2. Conti...solenoid and it will try to turn over a few times but very weak and eventually i lost power. I must mention i replaced both the starter and solenoid. Any ideas what it could be?
     
  3. Check your battery and the connections.
     
  4. Thanks im pretty sure the battery is good but i will double check the connections. Also i should add that before i sent the computer off it did the same thing when i turned the key but it would crank if i jumped the solenoid but of course not start because of the computer.
     
  5. You have a bad connection or possibly a bad solenoid
    Check voltage at the solenoid
     
  6. Fuel pump continually priming is usually bad fuel pump relay underneath drivers seat. Was that replaced?
     
  7. Update: Still having the issue. The weird thing is that it will fire right up one time and if i turn it off and try to crank it again its just a click and the dome lights, dash lights, and gauges go off-completely loses power. Then if I disconnect and reconnect the battery cables to reset it will crank up again. I replaced the solenoid again even though it was new because it had a warranty. I also got all new battery cables to be sure the connection is good and the battery is full charged. What else could it be? Why would it crank flawlessly one time and not at all the next? I'm at a loss. Appreciate any help.
     
    #7 cnorman31, Sep 13, 2017
    Last edited: Sep 13, 2017
  8. make sure the base of the solenoid has a solid ground to the body of the car
     
  9. Just to ensure the battery isn't getting weak. Put a DMM and ensure your alternator is charging. Then ensure your grounds are good.

    Also take a picture of your solenoid set up. Might help shed some light.


    But it kind of sounds like your ignition switch may be the culprit. Worth looking at, no use replacing unless its bad, just take a look at.

    https://lmr.com/item/LRS-11572A/79-93-Mustang-Ignition-Switch
     
  10. Here is some pics of my solenoid setup. With the way that the fender is shaped it doesnt allow the solenoid to lay complete against the body. As you can see there is a gap on one side. Is it suppose to be flush all the way around?
     

    Attached Files:

    #10 cnorman31, Sep 14, 2017 at 11:44 AM
    Last edited: Sep 14, 2017 at 12:01 PM
  11. No Crank checklist for 5.0 Mustangs

    Revised 24-Oct-2013 to update voltage drop figures.

    No crank, slow crank and stuck starter solenoid problems have the same root causes – low battery voltage and poor connections. For that reason, they are grouped together.
    Use the same initial group of tests to find the root cause of slow crank, no crank and stuck solenoid problems.

    Since some of the tests will bypass the safety interlocks, make sure that the car is in neutral and the parking brake is set. Becoming a pancake isn’t part of the repair process…


    1.) Will the car start if it is jumped? Then clean battery terminals and check battery for low charge and dead cells. A good battery will measure 12-13 volts at full charge with the ignition switch in the Run position but without the engine running.
    A voltmeter placed across the battery terminals should show a minimum of 9.5-10 volts when the ignition switch is turned to the Start position and the starter engages or tries to engage. Less than this will result in a clicking solenoid, or slow cranking (if it cranks at all) or a starter solenoid that sticks and welds the contacts together.

    Most auto parts stores will check your battery for free. It does not have to be installed in the car to have it checked; you can carry it with you to the auto parts store.

    The battery posts and inside of the battery post terminals should be scraped clean with a knife or battery post cleaner tool. This little trick will fix a surprising number of no start problems.

    The clamp on with 2 bolts battery terminal ends are a known problem causer. Any place you see green on a copper wire is corrosion. Corrosion gets in the clamped joint and works its way up the wire under the insulation. Corroded connections do not conduct electricity well. Avoid them like the plague...

    If the starter solenoid welds the contacts, then the starter will attempt to run anytime there is power in the battery. The cables and solenoid will get very hot, and may even start smoking. The temporary fix for a welded starter solenoid is to disconnect the battery and smack the back of the solenoid housing a sharp blow with a hammer. This may cause the contacts to unstick and work normally for a while.


    A voltmeter is handy if you are familiar with how to use it to find bad connections. Measure the voltage drop across a connection while trying to start the car: more than .25 volts across a connection indicates a problem. The voltage drop tests need to be done while cranking the engine. It's the current flowing through a connection or wire that causes the voltage drop.

    See http://assets.fluke.com/appnotes/automotive/beatbook.pdf for help for help troubleshooting voltage drops across connections and components. .

    attachment.php?attachmentid=64167&stc=1&d=1286329941.gif

    Voltage drops should not exceed the following:
    200 mV Wire or cable
    300 mV Switch or solenoid
    100 mV Ground
    0.0V Connections
    A voltage drop lower that spec is always acceptable.

    2.) Check the battery to engine block ground down near the oil filter, and the ground behind the engine to the firewall. All grounds should be clean and shiny. Use some sandpaper to clean them up.

    3.) Jump the big terminals on the starter solenoid next to the battery with a screwdriver - watch out for the sparks! If the engine cranks, the starter and power wiring is good. The starter relay is also known as a starter solenoid.

    The rest of the tech note only concerns no crank problems. If your problem was a stuck solenoid, go back to step 1.

    4.) Then pull the small push on connector (small red/blue wire) off the starter solenoid (Looks like it is stuck on a screw). Then jump between the screw and the terminal that is connected to the battery. If it cranks, the relay is good and your problem is in the rest of the circuit.

    5.) Remember to check the ignition switch, neutral safety switch on auto trans and the clutch safety switch on manual trans cars. If they are good, then you have wiring problems.

    Typical start circuit...
    Diagram courtesy of Tmoss & Stang&2birds
    attachment.php?attachmentid=21328&d=1080916057.gif


    6.) Pull the starter and take it to AutoZone or Pep Boys and have them test it. Starter fails test, then replace it. If you got this far, the starter is probably bad.


    Starter solenoid wiring for 86-91 Mustang
    attachment.php?attachmentid=52294&stc=1&d=1192414749.gif


    Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.
    attachment.php?attachmentid=53216&stc=1&d=1201020653.gif

    Electrical checks for the switches and starter solenoid

    Remove the small red/blue wire from the starter solenoid. Use a screwdriver to bridge the connection from the battery positive connection on the starter solenoid to the small screw where the red/blue wire was connected. The starter should crank the engine. If it does not, the starter solenoid is defective or the battery lacks sufficient charge to crank the engine.

    If the starter does crank the engine, the problem is in the clutch safety circuit (5 speed) or Neutral Sense Switch (auto trans) or ignition switch.


    See the Typical start circuit diagram above for wiring information for troubleshooting.

    You will need a voltmeter or test lamp for the rest of the checks. Connect one lead of the voltmeter or test lamp to ground. The other lead will connect to the item under test.
    Look for 12 volts on the white/pink wire when the ignition switch is turned to the Start position. Check the ignition switch first.
    No 12 volts, replace the ignition switch.

    The next step will require you to push the clutch pedal to the floor (5 speed) or put the transmission in neutral (auto trans) while the ignition switch is turned to the Start position.
    Good 12 volts, check the clutch safety switch (5 speed) or Neutral Sense Switch (auto trans) for good 12 volts on both sides of the switches. No 12 volts on both sides of the switch and the switches are defective or out of adjustment. Check the wiring for bad connections while you are at it.