Question about 1990 Ford F150

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I think I might have something else to add to my problems. All this time I've been saying the check engine light comes on when the truck engine shuts down. But instead, it's the battery light that comes on when the engine shuts down. Again, adding to my April 30th question on my F150 by maka2uli. Would this help to hopefully pin point the problem? Mahalo

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  • 17,970 Answers

If your battery light comes on, you either have a bad battery, bad alternator or poor connection somewhere in the charging system. While a F-150 can drive for a brief period without proper operation from the charging system components, odds are the car will not start once it has been shut off without the assistance of a jump. Trys this test:

1. Put on your gloves and remove the battery cables from the battery, using the battery terminal wrench. Remove the negative cable first.

2.- Clean any corrosion from the battery terminals and cable ends with the battery terminal cleaner and brush. Clean the inside of the cable ends to ensure a solid metal-on-metal contact once you reconnect the cable to the battery terminal. Visually inspect the battery cables; if there is any significant corrosion buildup on the cables, replace them.

3.- Reconnect the battery cables, positive side first.

4.- Check to see if the light is still coming on. If not, monitor it for the next week or so while driving. If it is still coming on, move to step 5.

5.- Take the flashlight and visually follow the battery cables away from the battery. At each connection, make sure the cables are making proper contact and do not have any corrosion built up at the connection. If there is corrosion, disconnect the negative battery cable from the battery, then disconnect the cable from the site of the corrosion and clean the area with the cleaner and brush. Reconnect the cables, connecting the negative to the battery last, once you have it cleaned. Continue to clean and inspect the cables until you have inspected them all. Recheck the battery light when you are done. If the light stays off, monitor it for the next few days. If it is still on, move to step 6.

6.- Drive your Town Car to a repair facility and have the alternator and battery tested. In the event you cannot drive it, you can either have it towed to the repair shop or remove the alternator and battery and take them to a parts store to have them tested.

Also, I suggest check with ths scan tool for other fault codes there.

Tell us news.

Posted on May 15, 2010

  • maka2uli May 15, 2010

    The original problem was the engine shutting off after about 10 seconds from being started. On some occasions, it will start fine, with a little high/low idling, and upon driving, there would be hesitations with jerky actions. Also, upon driving, the engine would shut down when the gas is released. I had originally stated that the check engine light would come on when the engine shut down, but all this time it was the battery light coming on. I hope this will help. I had this truck sitting for three years, without putting it in storage, so to get it back on the road, it will cost some tax money. But I do want to get it back on the road. I'm sure you understand.

    Mahalo and Aloha

  • ZJ Limited
    ZJ Limited May 15, 2010

    New alternator, well check the serpentine belt if you haven't done so
    yet. Get a voltage tester and check the voltage at the battery with the
    motor running, it should 13.2v to 14.5v. Have someone step on the gas
    pedal [increase rpms to 1000], if the voltage drops, look at the belt
    again, if it goes over 15 volts, check your entire charging system,

    Check all the fluids (level and quality), if is necesary, change it.

    If you are reading this, check this comment that I find in other sites...

    I just experienced a sudden high idle on a 2000 Ford Ranger engine type "U" stuck at 3,000 rpm and can not touch the gas pedal
    without killing the engine. Cranks OK but will not drop idle once the
    truck warms up. Problem is Idle Control Valve IAC either stuck, or
    Engine Control Sensor ECS has stopped talking to IAC, telling it engine
    has reached operating temp and to drop idle speed. There was no "Check
    Engine" light.

    To try to correct in the field. The IAC is a solenoid looking devise
    on top of the air intake duct, attached to the carburetor, next to the
    gas pedal linkage box. DO NOT TOUCH THAT SCREW ON THE PEDAL. That's not
    the problem. Stop the engine. Take a plastic screwdriver handle and tap
    the IAC. Re-start engine. If still in high idle, tap the IAC again,
    keeping in mind you can hit it too hard and damage the unit. Check for
    loose wiring at the IAC or ECS located on the block, below the IAC to
    the passengers side, and may have one or two wire harness. If still not
    fixed, shut off engine and if possible take the IAC off, two bolts maybe
    a #8 socket, and spray some carb cleaner flushing out the unit.
    Re-install, try again. If still not fixed, Carefully open and check the
    water level in the engine. WARNING: Cooling system could be loaded with live
    steam or boiling water under pressure. BE CAREFULL. If you do not see
    water at the cap, pour only 1 cup full of cold water into the radiator.
    More may damage engine cooling jacket. Listen to the falling water and
    try to determine if the radiator sounds empty or low. Do not depend on
    the radiator reservoir level. IF, you are low on water, then the ECS
    does not have any water temp to read, then claims engine is cold to the
    IAC. Wait until engine cools to add water / anti-freeze to full. IF
    still not fixed, then the IAC / ECS are defective and need to be

    I changed the IAC for safety, and filled the radiator. Truck runs better than ever. I had some anomalies in the temp gauge, with low
    or no heat to sudden high heat back to normal range.

    Take it from a man stuck in Hogansville, GA for the night...Spartan

    Good luck.



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