N14 starting issue

Discussion in 'Trucks [ Eighteen Wheelers ]' started by limespreader22, Dec 15, 2012.

  1. limespreader22

    limespreader22 Bobtail Member

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    Feb 19, 2012
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    I have a N14 in a 1995 FLD that I am having problems getting started. When i turn the key and the indicator lights for the air, oil psi etc come on if they don't flash it will not start. If the lights all flash then it will start fine.Sometimes the lights wont flash without turning the key off then back on. Even if the lights dont flash it will still crank fine it just will not start. I have cleaned most of the ground wires and replaced a couple relays and ignition switch while trying to find the problem. I'm hoping you guys may have some new places to look thanks.
     
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  3. BigCam9670

    BigCam9670 Medium Load Member

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    Around the starter area there are 2 connections for the ECM power and ground feed. Make sure they are all clean and tight. There are also one or two fuses as well in that area for the ECM. You can also check the ECM plugs for corrosion or moisture.
     
  4. limespreader22

    limespreader22 Bobtail Member

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    Feb 19, 2012
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    Fuses appear to be ok. I cleaned th e area where the ground wire runs too. I also had a guy bring a good ecm he had to see if mine was tye problem still wouldnt start
     
  5. limespreader22

    limespreader22 Bobtail Member

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    Feb 19, 2012
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    Fuses appear to be ok. I cleaned the area where the ground wire runs too. I also had a guy bring a good ecm he had to see if mine was the problem still wouldnt start.
     
  6. Heavyd

    Heavyd Road Train Member

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    The yellow "check" or "warn" engine light, and the red "Stop" engine light are actually turned on by the ECM at key on for a bulb check. This also shows the ECM has booted up at key on. If you turn the key on and get no lights there may be an ignition power feed problem to the ECM. If the other warning lights in the dash are also not lighting up properly at key on it sounds more like an ignition power problem, could even be just the key switch.
     
  7. flc120

    flc120 Heavy Load Member

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    Miami,FL (yeah i know :( )
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    maybe you might have with the ignition key switch as well.
     
  8. limespreader22

    limespreader22 Bobtail Member

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    Feb 19, 2012
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    Thanks for the replys, have already replaced the ignition switch along with two relays inside the cab.Also thr lights will come on they just have to flash or it will not start.
     
  9. Heavyd

    Heavyd Road Train Member

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    Ok, that does ring a bell, I know what you mean by having them flash. I see it more as a single blink, but same problem, lights on solid no start. Lights come on, blink, and it starts. I had a truck do the same thing. The truck ended up getting a complete new engine harness, short answer. Long answer - truck had starting problems like you mentioned. Very hard to duplicate, would only act up once in maybe 30 attempts. I can't remember if it was logging 434 or not, (low battery supply), but we wired in all new power wires to the Cummins harness with new fuse holders. Truck came back with same problem. I basically opened up the whole actuator harness to expose the battery supply wires to the ECM. We all know there are two main battery supply wires to the engine. Each wire is protected with a 15 amp fuse. Inside the actuator harness one wire splits into two and the other splits into 3 with butt connectors. This is inside the Cummins factory harness, not the OEM side. What I found was the one butt connector that turned one wire into 3 was totally corroded. So I replaced that butt connection and the other one. Out of the two main battery supply wires that come into the harness, they turn into 5 power supply wires. 4 go to the ECM and the 5th is power for the datalink connector next to the ECM. Also, the main single ECM ground wire to the batteries actually is 3 wires out of the ECM and is butt connected inside the harness aswell. If you lose power or have a bad ground at one of these pins the ECM will not work properly and also may not be able to detect a fault either. So after we made those wiring repairs the engine would start just fine, but then after we started getting all kinds of other problems with other circuits. The problem was the engine harness it self. It was in such poor shape because the wiring and insulation was brittle from age and heat. The wires were breaking internally when the other wires near by were handled. It just got to the point where enough was enough. Replaced the whole harness and the engine has been fine. Not every truck ages the same, so I am not saying you need a complete harness. What I would do is at least check the powers and grounds at the "Actuator" connector at the ECM. This is the top inner one. You need to test in a special way. You would remove that connector and check for battery voltage at pins 20, 21, 22 and 23. You need to insert the proper test terminal inside the hole in the connector. Anything too big will damage the terminal inside. If you have a good power wire there it should be able to light a head light. So what I do is insert the test terminal with alligator test leads to a spare head light and then have another alligator test lead connecting the head light to ground. If the power is good at the ECM connector pin, it will light the head light. With the head light lit, grab the wiring harness and wiggle it all over. If there is bad or weak connection in there wiggling might help you find it because the head light will start to get dim or go out. Do the same with the ground pins 9, 25 and 27. Hopefully you are able to find something there. Good luck!
     
  10. jpracer1

    jpracer1 Medium Load Member

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    Nov 26, 2009
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    also check the power wire for your ecm at the battery terminal
     
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