'88 Lx 5.0, Hard To Start After Warm Or Hot

Discussion in 'Fox 5.0 Mustang Tech' started by Spyky3, Nov 20, 2013.


  1. Spyky3

    Spyky3 New Member

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    Is it the starter? Own 88 for last 12 years, all stock, V8, k&n air, auto, no problems or fixed-it myself. Oil drips got bigger in center. Got lazy and let the local shop replace rear main seal between engine/ trans and intake manifold gasket to stop oil leak. Got it back and car hard to start. Before car would crank couple time and fire up. Replaced premium starter from O'riellys Auto Parts and charged battery. Car starts fine cold but struggle after hot or warm.
    Another shop check timing ok, said starter draining heavy... Bad starter? Grounding problem? 6 months later, oil start to leak again... Thanks in advance!
     
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  2. A5literMan

    A5literMan Mustang Master

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    Check wiring first but Sounds like the starter to me or the ground. Have the codes run before you start replacing more parts also.
     
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  3. jrichker

    jrichker StangNet's favorite TOOL SN Certified Technician Founding Member

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    You posted a TECH question in Talk. This limits your chances of getting some really good advice, since most guys aren't looking for Tech stuff in the Talk forum.

    My advice to you is to twofold:
    1.) Send a PM to one of the moderators and have your thread moved to 5.0 Tech
    2.) Next time you start a thread, think about where it goes. If you are new to Stangnet, please read the terms of service and give extra thought to where your new thread belongs. There is some help in the text below to help you find the best place to start your thread.
    General tech problems go in 5.0 Tech. Tech is for suspension, electrical, brakes, body, engine repair and general troubleshooting on the computer & trouble codes

    Tall tales about your 5.0 Mustang, pictures of your 5.0 Mustang project and stories about your last trip to the race track go in 5.0 Talk.

    Do this and you'll get the best answers quicker and not get lost in the maze of posts about everything but the type of problem you are having.
    @Noobz347 please move this to Tech
    Having said that, here’s some help…


    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. .

    [​IMG]

    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
    [​IMG]


    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
    [​IMG]


    Starter solenoid wiring 92-93 Mustang or earlier Mustang with upgraded high torque mini starter.
    [​IMG]

    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.
     
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  4. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor Admin Dude

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    Thread moved
     
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  5. GoldenEagle91

    GoldenEagle91 Member

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    I have heard of this before where the starter gets too hot and won't start up again until the car has cooled down some. I'm not sure if there is some heat shielding to prevent this but you're not the first person that I've heard of this from.
     
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  6. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor Admin Dude

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    There is and you are correct. This is a common problem. Heat shielding IMO, is a pain in the ass... A high torque mini-starter is my preferred method for that particular problem, along with some really large gauge, power and ground wires.
     
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  7. GoldenEagle91

    GoldenEagle91 Member

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    So those things are really the best solution available if that is the case of whats going on. Good deal, thank you for confirming.
     
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  8. Noobz347

    Noobz347 Stangnet Facilities Maint Tech... Er... Janitor Admin Dude

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    Ah... I neglected to mention: Electric fans help this situation too. Particularly those with a shut-down timer that runs the fan(s) for a couple minutes after the motor is shut off.
     
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