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  1. #1
    Bobtail Member
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    92' Cummins N-14 Wont start need advice

    Purchased this truck 1 yr ago sat in the yard since went to fire it up few weeks ago wont start . First thing I checked for voltage at the fuel solenoid with key switch turned to on position . Sometimes i have it sometimes i don't . The truck turns over . Had a mechanic friend of mine check it out he can get it to fire with ether . But he's telling me to either have someone with a computer check it out . Or to just change out the cam sensor and crank sensor . The sensors are 48 bucks each . I guess my question is what sensor would cause the truck not to start at all ? Or could it be the Ignition Switch itself because of the voltage problem to the fuel solenoid i know you need power there at all times . And for some reason the headlights are tied into the ignition system .When i turn the lights on the dash lights up like the key is turned on and you can push the button and turn the eng. over .The guy that had the truck before me is a real butcher when it comes to wires . I'm trying to avoid a costly ecm i hope that isnt the problem . I dont think it is because the truck will fire with ether . Any tips would be great Thanks !


  2. #2
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    simple things to check, grounds to the frame, I have seen one bad or weak battery keep a N-14 from starting (i would start at the battery box), sounds like a wiring issue, I have had a N-14 to run on either but still need a ecm in the near future, great motor but the worst computer and electronics I have seen

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  4. #3
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    I'm not sure of the lights like stop engine, shut down, etc. Are any of those lit or even present?

    The ECM for those engines has to have at least 6 volts or maybe more before it will allow starting and continued running, and the way many of them are wired, one battery is supplying that voltage, not the whole battery set in parallel, that is why 1 battery being bad can keep the engine from running.Somebody that can read the ECM with a computer would be the best bet for diagnosing the problem first.

    It does sound electrical and a truck that hasn't been running is definitely bound to have more than a normal amount of those.

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  6. #4
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    Insite (Cummins electronic diagnostic tool) won't be needed here. Throw me an engine serial number so I can be for sure on the pinouts, but what you need to do is ohm the fuel sos wire and if it is ok (also check the eye connector - those are bad about making bad connections) check the unswitched battery supply and grounds. If they are not ok, check fuses. There is a fusable link going from starter to engine block - those like to blow on volvos.

    Btw, one bad battery won't keep it from running just as long as the set still has enough cranking amps. The voltage will be the same no matter where you take it in a parellel setup. Cummins has to be over 9.2 to throw voltage at the fuel sos or else it will throw a 434 code.

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  8. #5
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    Engine # 11653850 Hope thats the number you are looking for. im not near the truck right now . I hope to be working on it by Wednesday . So what you are saying is check that single wire and its eye connector that goes to the fuel solenoid . I havent traced that wire back to see where it comes from . My guess would be the ECM Or one of those pins ? But i think i get what you're telling me here . And check the fuseable link and fuses . Thanks for the Insite this has got to be something simple . This truck has been known for its Tank like ability. Thats why i bought it . I just let it sit up too long in the Hot Florida Sun and she's mad at me right now .

  9. #6
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    Yes the wire does go back to the ECM. Now if you're not comfortable....let me know.

    The rear of the ECM is where the connections are. There are 3 connections. The top outside is OEM connector, inside top connector is the Sensor connector, and the only bottom connector is the Actuator connector. All of the connectors are held on with little screws, size 9/32". We're going after the Bottom connector, so the OEM connector will probably have to disconnected too. Make sure to turn off the key before doing this. After you have the actuator connector off look at the face (where it hits the ECM) of the connector. There will be three columns of pins. They are numbered vertically with the #1 pin being at the top left of the face of the connector. So if you count, the first column is 1-9, second column is 10-19, and third column is 20-28. Now to be sure with the right connector (I'm sorry sometimes I do get the sensor connector and the actuator connector confused ), we look at the face of the connector and between pin 10 and pin 20 there should be a notch. There will also be a notch between 19 and 28 and one more between 6 and 7. If the notches are not in those locations, we've got the wrong connector...so the right one is the only connector still connected to the ECM.

    Ok, now that we know we've got the right connector we need to start testing. Now, 20 thru 23 will be unswitched battery supply. Pins 09, 25, and 27 are grounds. What we need to do is test power at pin 20 and ground at pin 09. If we have power, we will move our positive lead to the next power pin and so on. If we do not, move the negative lead to a good known ground and test again. If we have power, we know we have a failed ground to the ECM. If we do not have power, we need to check the fuses - usually located in the battery box. Now lets back up and assume we had power at our first test. We use pin 09 as our constant ground and test all of the power pins. If they all have power, then we choose one of our power pins to be constant and then move our negative lead to the other two ground pins and test them. If all tests good....we're not in good shape.

    The fuel shutoff solenoid is pin 16. Ohm from pin 16 at the ecm connector and eye connector at the solenoid. Make sure to disconnect the wire at the solenoid to get an accurate reading. If that tests good....we need to move on to our switched battery supply pin or ignition wire. Key switch input is pin 26 on the same connector. Its ok to turn the key on if we already disconnected the ECM....just make sure you never disconnect or connect an ECM with key switch on. With the key on, measure voltage from pin 26 to pin 09 (ground pin). If we are within 1 volt of battery voltage, thats good.

    If all tests good, take the truck to the shop to confirm that there are no codes in the ECM. If there are no codes (well there can be codes, just no codes related to not starting the engine) we need to put an ECM on it. Oh boy....if you have any questions...don't hesitate.

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  11. #7
    Light Load Member coalhauler625's Avatar
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    have you unhooked the batteries let it set for a few minuites then re-hooked them and tried ......alot of times i have seen these CELECT systems lock-up computer just uhook bat. so they can reset or re-boot

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  13. #8
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    WoW man this is gonna be fun ! I used to work on Air Conditioners and electrical diagnostics is fun to me for some reason . Like solving a puzzle . I'll be working most of this week i hope to get to the truck by Wednesday definetly get to the bottom of this by Sunday . Thanks for everyones help . I think with proper patience i can sort this out . But if i totally get confused i will definetly stop and call in someone who is familiar with these Engines . Worst case ...what ECM is bad ? I know that can be pricey from what ive seen between 1800-2800 bucks ? Thanks allot vegetto05 for taking the time to explain. Greatly appreciated I'll have an update by the weekend .

  14. #9
    Road Train Member Heavyd's Avatar
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    At key-on, if the ECM is booting up it will turn of the Check-Engine, Stop-Engine lights. If you don't get these lights the ECM is not booting. I have seen the ECM connector screws break at the ECM so I try to remove those last and check the simple things first. The ECM gets it power from a separate power harness. Usually straight from the batteries or from the starter positive post. The ECM power is always protected with a fuse. Locate the power harness and trace it. Look for damaged or corroded locations and find the fuse! Check to make sure it isn't blown and the terminals in the fuse holder are ok. If you are getting your Check engine lights then the ECM is getting key power. Disconnect the single wire to the shut-down solenoid and connect a 12 volt test light to the end the wire and a good ground. Turn the key on and your test light should be lit. That means the shutdown solenoid is getting power. No light, something wrong with ECM or ECM not powered. Now, on a 92, I have to guess the tach gets a separate signal from a sensor on the bell housing because it isn't new enough for the gauges to get the data from the ECM. If the ECM feeds the tach with data, then if the tach shows some engine rpm while cranking you know the ECM is powered and crankshaft position sensor is good too! Hope this helps.

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  16. #10
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    Quote Originally Posted by Heavyd View Post
    At key-on, if the ECM is booting up it will turn of the Check-Engine, Stop-Engine lights. If you don't get these lights the ECM is not booting. I have seen the ECM connector screws break at the ECM so I try to remove those last and check the simple things first. The ECM gets it power from a separate power harness. Usually straight from the batteries or from the starter positive post. The ECM power is always protected with a fuse. Locate the power harness and trace it. Look for damaged or corroded locations and find the fuse! Check to make sure it isn't blown and the terminals in the fuse holder are ok. If you are getting your Check engine lights then the ECM is getting key power. Disconnect the single wire to the shut-down solenoid and connect a 12 volt test light to the end the wire and a good ground. Turn the key on and your test light should be lit. That means the shutdown solenoid is getting power. No light, something wrong with ECM or ECM not powered. Now, on a 92, I have to guess the tach gets a separate signal from a sensor on the bell housing because it isn't new enough for the gauges to get the data from the ECM. If the ECM feeds the tach with data, then if the tach shows some engine rpm while cranking you know the ECM is powered and crankshaft position sensor is good too! Hope this helps.
    You sure do like to do a lot of assuming. Just because a circuit works the one time, it doesn't mean it will work the next. This is why it is important to do a continuity check. And if the ECM power fuses are getting power from the starter then we have got something wired not to Cummins spec. Cummins specifically states they have to come off the battery... You cannot assume if the lights are on that everything is ok. Like I said before, if a circuit works once, it may not twice. And if its not lighting up, it may be a bulb and damaged circuit for the light itself, not necessarily indicating anything wrong with the ECM. Using a test light at the solenoid will work sometimes....but making sure the voltage is with a volt of system voltage is a good thing...thats why we need to use a multi meter.

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