Cranking with key off

Discussion in 'General IH Tech' started by Tiki_scout, Apr 16, 2019.


  1. Tiki_scout

    Tiki_scout Farmall Cub

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    Motor continues to crank after key is turned off. Motor hasnt started in years and the wiring harness is nasty. Is this an ignition switch issue or wiring from the bulkhead to the starter? Not sure if I maybe have a wire misplaced. It has a new battery, starter, pertronix. 4cyl 196.
     
  2. JeffSColorado

    JeffSColorado Farmall Cub

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    Could be a bad ground on the starter motor.
     
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  3. Mattd

    Mattd Farmall Cub

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    I had a similar issue and it was because of my timing.
     
  4. Tiki_scout

    Tiki_scout Farmall Cub

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    Ill open the harness to check the ground. Maybe I should start from zero with the distributor. TDC and be sure it's in the right place.
     
  5. mallen

    mallen High Wheeler

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    A sticky solenoid or sticky ignition switch should act as follows. You turn the switch to the on position.The starter motor engages and starts turning and does not stop when you release the key. If you disconnect the battery, it of course stops. If you reconnect the battery, it starts going again. Sometimes it might stop on its own, and sometimes it might not start back up when you reconnect the battery until you turn the key to start again. (or it might always) The key is, the solenoid or ignition switch sticks. But removing the power does not (at least does not always) reset everything. If thats the case then its likely a sticky solenoid or ignition switch. Try taping on the solenoid with a wrench or a small hammer (dont whang on it, just a nice firm tap) when its running and see if it stops. Whatever you do, be careful not to let the starter run for more than 15 or 20 seconds before letting it cool for 5 minutes. Many a good starter has been fried by people trying to diagnose starting problems.

    It could however be a short somewhere. Is the symptom that it sits there not cranking (in other words, its NOT that whenever you connect the battery, the starter motor goes, no matter what) , but when you turn the key to the start position then back it keeps cranking? Does it keep doing it when you release the key? What about when the key is turned to the OFF position? Consider the following:

    solenoid-for-delco-5mt-8mt-10mt-20mt-22mt-25mt-27mt-starters-245-12004-2.jpg

    The MTR terminal provides power to the starter motor when the solenoid engages. The Bat terminal is connected to the positive terminal of the battery. The S terminal switches the solenoid "ON" when it is connected to 12V (such as the positive battery terminal) The R terminal is used to bypass the ballast resistor when starting the vehicle and connect the positive side of the coil directly to the 12V battery to make starting easier. Consider what would happen if somewhere in the vehicle (whether it be in the harness, two wires someone connected together that should not be, or an internal short in the solenoid) the R wire was connected to the S wire.

    The vehicle is sitting there doing nothing. The S terminal is not connected to anything. The MTR and R terminals are similarly disconnected. Now you turn the key to the start position and the S terminal is connected to 12V. The solendoid engages and connects the MTR terminal and R terminal to 12V. The starter motor starts turning. Now you switch it to the off position. The ignition switch disconnects 12V from the S terminal, but the R terminal is still connected to 12V,and thus holds the S terminal at 12V and the starter wont turn off. Its a latching relay.

    To start with I would COMPLETELY disconnect the R terminal AND the S terminal from the starter. Now use a screwdriver to short the BAT terminal to the S terminal. The starter motor should engage and run, and then stop when you disconnect it. If it does NOT stop, replace the starter solenoid.

    Next, reconnect the S terminal. Turn the ignition key. The starter motor should engage. When you release the key, it should stop. If it does, then the R lead is probably crossed somewhere with the S lead and thats why your latching up like that. Reconnect the R lead and see if the problem comes back. if it does, thats what you expect. Check for continuity between the wire that goes to the R lead and the wire that goes to the S lead. It could be as simple as degraded insulation allowing the wires to contact together in the harness.

    If the problem does NOT come back when you reconnected the R lead, then look carefully at everything you disturbed. Chances are, there were two wires with bad insulation or some such that were touching and you moved things a bit and they are no longer touching. Find that and fix it.

    Edit: Also check to see if the previous owner put a relay in to operate the starter. Sometimes this is done to get around bad wiring and connections elsewhere and I can imagine a few ways this could cause your problem if it was done wrong.
     
    Last edited: Apr 16, 2019
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  6. mallen

    mallen High Wheeler

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    Your describing "dieseling" when the engine continues running after being turned off due to a hot spot in the engine igniting the mixture. He said that his engine has not run in years and it sounds like, it still does not run. (Question to the OP, am I correct in reading your post as the motor is NOT running at all?)
     
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  7. Tiki_scout

    Tiki_scout Farmall Cub

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    Wow. Thanks a lot. Yeah, this thing hasn't run in years and someone tried to get it going but gave up so everything is hacked. There are quite a few wires that have burnt insulation. I'll disconnect the terminals and fix the burnt wires before checking. I'm pretty sure that will be the issue.

    The starter is a fresh rebuild and that top bolt was a pain in the ass so I hope it's just some bad wiring. Thanks again. I'll let you know if I need more help.
     
  8. stevewillis

    stevewillis Farmall Cub

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    Test for voltage at the S terminal of the starter. If there is voltage present at any time the ignition switch is not in the start position, there is an ignition switch problem. Take the lead off the S terminal and test it directly if preferred to avoid exercising the starter in this condition.
     
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  9. mallen

    mallen High Wheeler

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    I have a box end wrench that I ground the end thin on to get it to fit in there.
     
  10. Tiki_scout

    Tiki_scout Farmall Cub

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    Got the starter straightened out. Now have no spark. So on to the next problems to sort out.
     
  11. mallen

    mallen High Wheeler

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    What was the problem with the starter? Do you have points or an electronic ignition?
     
  12. Tiki_scout

    Tiki_scout Farmall Cub

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    The S and R wires were touching. Theres a metal wire clamp near the end of harness cutting the insulation. The connector for the R terminal was loose and deteriorated too.

    I should have taken the time to sort through it. That explanation was super helpful though.
     
  13. Tiki_scout

    Tiki_scout Farmall Cub

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    I
    I put a pertronix unit in it.
     
  14. Tiki_scout

    Tiki_scout Farmall Cub

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    When I changed my starter I found this old wrench that fit perfect.
     

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  15. mallen

    mallen High Wheeler

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    Cool. First, dont leave the ignition switched into the on position without the engine running for more than 20 seconds at a time or so ,or you could destroy the pertronix, if its not already gone. With the ignition on, there should be voltage at the positive terminal of the coil. There is usually a resistance wire running back to the ignition switch. That resistance wire takes the place of the ballast resistor. The other side of the coil goes to the points or the pertronix. I suggest the following. Make sure there is voltage at the positive terminal of the coil when the ignition switch is turned on. Disconnect the coil lead from the distributor and put it near something grounded like a bolt on the engine, but keep it away from fuel sources that could ignite. I usually stick a screwdriver in it, and then sit it near a bolt or something so I can see it spark. Next, take a jumper cable, put one end on the battery negative terminal. Touch the other end to the coil negative terminal for a half a second or a second then remove it. When you remove it, you should get a nice blue spark from the HV lead. If you do, then you know the coil is working. If you leave your meter connected to the positive terminal, you should also see the voltage drop as you connect the coils negative lead to ground if you have a balast resistor (or resistor wire). If there is no ballast resistor or resistor wire, it will stay more or less at the battery voltage (12V or so). You SHOULD see something like 6 or 7 volts when it drops. If you get the voltage drop but no spark, check the HV lead to the distributor (which is now disconnected and sitting about 1/8" from a bolt with a screw driver in it). If the HV wire is good, then the coil is probably bad.

    Next, connect the meter to the NEGATIVE side of the coil. With the ignition on, you should still see around 12V. Rotate the engine by hand with a wrench. (Its also ok to crank the engine and look to see if you get spark,but NEVER turn the engine backwards, only go in the forward direction) As the engine rotates you should see the voltage drop WAY down as the igniton module switches the positive lead to ground, like maybe 1V or zero volts and you should be getting spark. Make sure you dont leave it sitting like this for very long. If you leave the pertronix on without the engine running for very long you will destroy it. If your not getting that, then either the pertronix is bad or its not connected properly. I would just go back to points, gap them with a business card or match book, and then try again. In other words, install and trouble shoot the pertronix from a known working state of the engine.

    If you were NOT getting spark, and fixed something, then you may have just fixed the engine. If it still not starting, then continue troubleshooting.

    By this point, you should now be getting spark to the distributor. (reconnect the distributor/coil HV lead) Disconnect a spark plug wire and put an spark plug in it (like an old one that you know is still good, it can be from any vehicle, it just needs to fit the spark plug wire) Alternately, you can just do the same trick with the screw driver you did before. The idea is to set up something where you can see the spark. Crank it over and make sure your getting spark at the wire. Check the others as well. If your getting nice blue spark at all the wires, then theres another problem preventing it from starting. Reconnect the spark plug wires.

    The next places to go will be to double and triple check the firing order, even if you think you checked it, even if you KNOW you checked it before,and check the timing.
    Other things that can get you is lack of fuel (even though you checked it, check again) or too much fuel. (Like flooding, to check,remove a spark plug and see if its wet with fuel. if it is, disconnect the ignition positive wire, and crank the engine over with the plugs removed to clear it) A spray of starter fluid into the intake can spot no fuel, it will try to start for a second then die)
     
    Last edited: Apr 17, 2019
  16. Tiki_scout

    Tiki_scout Farmall Cub

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    So, key on, coil wires are connected to pertronix and one wire connected to R terminal on starter. I have 12 volts at battery terminals but nothing at starter. R terminal has zero with key on. What am I missing? Battery cables? Ground wire? I have ground from battery to block, block to body. The ignition cranks so I have cranking power. I should have power with key on but not cranked correct? Ignition wire should go to S terminal?
     
  17. mallen

    mallen High Wheeler

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    There is a wire from your igniton switch that goes to 12v when you turn the key to the start position. That wire should go to the S terminal on your starter. There is another wire from your ignition switch that connects to 12V when the switch is in the ON position. Its usually a resistance wire, but if not you may need a ballast resistor in the circuit. That wire goes to the positive side of the coil if its a resistance wire. If not, then it goes to a ballast resistor and the other end of the ballast resistor goes to the positive side of the coil. The R terminal from the starter also goes to the positive side of the coil.

    With the key in the OFF position, there should be no voltage on the S terminal of the starter, the R terminal of the starter and the positive terminal of the coil.

    When you turn the key to the ON posiiton, you should now have between 6V and 12v at the positive terminal on the coil. Whether it is around 6 or around 12 will depend on the poisition of the distributor and whether the points (or their electronic equivalent in the ignition module, pertronix ,etc) are closed. If they are closed, then the circuit is completed and you should see around 6V, becuase the balast resistance is dropping about 6V. If they are open, no current flows so the ballast resistance has no voltage drop across it and you see the full battery voltage (12V or so). There will be 0V on the S terminal (because if there was voltage there, the solenoid would engage and the engine would start cranking). There should also be 0V on the R terminal (becuase the R terminal is controlled by the S terminal.) Dont leave the key in the start position without it running for more than 20 seconds or so or you could damage the pertronix.

    When you turn the key to the START position. The S terminal on the starter should have 12V. The solenoid should engage, and the starter motor should start cranking over the engine. When the starter solenoid engages, the R terminal should now read 12V or so. The positive terminal of the coil should also read 12V. (The purpose of the R terminal is to provide extra voltage to the coil to aid in starting, but if this was left on, it would overhead the coil. So its only applied during starting)

    Did your vehicle originally have points? If so, go back to the points and start from there. Once you have it working with the points, THEN you can go back and try the pertronix.
     
  18. Tiki_scout

    Tiki_scout Farmall Cub

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    Ugh. Ok. I'll try to check those things tomorrow morning. The points were trashed that were in it. I can grab another and check that.
    I've run pertronix before on a sorted out car without a ballast and it was fine and I know pertronix doesnt recommended them.
    I think starting with checking the two wires from the ignition will be smart. Thanks. I'll let you know
     
  19. scoutboy74

    scoutboy74 Lives in an IH Dealership

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    Knowing some basic vehicle data is often helpful in sorting through these issues. If this is the 800 model in your avatar, the stock resistor wire would likely be under your dash. They didn't move that wire to the engine side until a few years later. As for whether your module needs resistance or not, that may depend on the specific module number. Maybe it needs added resistance and maybe not. Also, 4 cylinder engines have different resistance requirements than 8 cylinders.
     
  20. Tiki_scout

    Tiki_scout Farmall Cub

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    I'lI check it out. Under the dash looked unmolested except for someone splicing in a new ignition switch. I have a diagram, I just need to decipher it.


     

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