HELP!!! Silverado stayed running without the key in the ignition switch

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by sysco, Oct 25, 2011.

  1. sysco

    sysco New Member

    Hopefully someone can help me out here? I have a 2008 silverado crew cab which i am recently having problems with. Short story I took it in for its regular oil change to the dealer waiting in my truck til the guy came back (truck is on with engine running) got off guy tells me to give him the keys I reached in to shut the truck off, turn the key to off position and took the key off gave it to the guy but truck didnt shut off till about 5 seconds of taking the key out.. Guy told me that was weird that its not suppose to do that (i could of told you that) anyways he told me here turn the truck back on. So i did it turn on find trun it back off again and it stayed on runnong for another 10 seconds and started to shake and engine slowly dieing off. This time engine light came on. Guy told me try again.. Same thing happen truck stayed on a little longer this time till it die off by itself. The dealer guy wanted to charge me $100 bucks so one of there tech can take a look at it only but i didnt and dont have the money right now ( wifey just had a new born a week ago). So i told him change my oil and ill have to bring it back some other time. Truch hasnt done it again but afraid it will sooner than later. Ive notice it doesnt start on as fast and strong as it use to honestly and the engine light disappear. Dont know what it can be and really dont have the money to waste right now but need to get it fix asap before it gives me more problems. I had a friend told me it could probably be the ignition switch gone bad that it is a common problem on the chevy. Anyone have any ideas?

    ** Also truck runs fine when its on its just the matter of once you shut it off engine still running for a couple of seconds before dieing off by itself**

    SILVERADO3 New Member

    OK i may be way off on this but i would think it could be a ignition switch issue, such as when you turn the key off the signal from the switch to the ECM it still flowing and then it slowly fades off, so some sort of short in that not sure how you could trace the wires on that but try to get a wireing digram of the ignition system. check amps on the wires maybe. Hope that gives some ideas
  3. Caddiac

    Caddiac Epic Member 5+ Years 1000 Posts

    Congratulations on the new baby and hate that you are having a problem that most Ford guys would love: the truck won't STOP running. The ignition in my 98 has been acting weird for some time. I can pull the key from the ignition while the truck is running. If you are not careful, you can turn the engine off without putting the key in the off position. The key will come out in the accessory position and you can turn the ignition with no key and start the truck.

    I am thinking my problem is in the ignition with, any chance yours could be similar?
  4. GM Customer Service

    GM Customer Service Epic Member 5+ Years 500 Posts

    I would also be willing to look into this for you with the last eight of your VIN. Please feel free to contact me privately. Thank you in advance.

    Tricia, GM Customer Service.
  5. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Any type alarm, anti theft, or remote start system on the truck?
    My wifes HHR remote start system had a little issue of starting the car for her whenever she used the remote to lock the doors, GM fixed the problem right away without any hassles, they said it was a safety issue and they assumed all cost's.
    If it's all factory equipment they may do the same for you.
  6. sysco

    sysco New Member

    SILVERADO3 ill take a look i really dont like to mess wit the truck being that that seem to be like an electrical problem dont want to mess anything up more than what already is but doesnt hurt to try thanks ill let you know what i come up with.

    Caddiac Thanks..Yeah the engine is still running without the key in it and it either shut off after 5 to 15 seconds or more or it slowly starts to shake till it dies out on its own.

    GM Customer Service Thanks but how can you tell what it is by the vin number (just asking) since the dealer never did have the tech check it out since i didnt have the money to pay them for it?

    tbplus10 Has no remote start what so ever and everything is stock. The only thing i change were the headlights and tailights. My warranty expired on Feb of this year is what the guy told me so i wasnt cover thats why he ask if i wanted his tech to take a look but he was going to charge me to check it out.

    I dont have the truck right now with me since i let my dad borrow it for the weekend but once i get it back ill take a look at it and see what i come up with.
  7. GM Customer Service

    GM Customer Service Epic Member 5+ Years 500 Posts

    I would be willing to look into this with the last eight of your VIN. Please feel free to contact me privately. Thank you.

    Tricia, GM Customer Service.
  8. Jdardenne3

    Jdardenne3 New Member

    I have an 07 gmc sierra and my engine stays running after I take my key out. All of the lights go off but engine stays running like if I had my key turned on! The only way to get it to turn off is to open driver door then it shuts off. Sometimes if I take keys out and leave it running and open my door and close it for alittle while then I try to start my truck there is no response! As soon as I take keys out and open door again and then it starts perfectly fine! What could be making my truck stay running while keys are out?
  9. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    You've piggy backed onto an old thread, but that's ok. The MODs may want to start a new thread.

    Here is what I suspect.........thanks to your additional info about opening the door and then the engine shuts off.

    That door thing is the key (in my opinion). Normally, turning off the key and not opening the door would shut off the engine, but keep the things like the radio operating for 10, or so, minutes. This feature is called "Retained Power" and opening the door will turn it off.

    This retained power thing is done with a couple of different methods. The older trucks use relays, the newer trucks are computer controlled. The '08 trucks use the newer method, I'm not sure about the '07 trucks. But, I don't think that matters.

    I suspect, there is something "back feeding" the ignition circuit. What I mean by that, is the key is turned off and the ignition voltage is removed, however, it is replaced by the Retained Power voltage. Open the door, and all RP voltage, included this backfeed, is removed.

    You need the find the component that is "leaking" this RP voltage. It could be the ignition switch. It could be a couple of wires shorted together (where, I don't know). I'd start with the ignition switch, just because it's cheap and because it's easy to change and because they are known to fail.
  10. j cat

    j cat Epic Member 5+ Years 1000 Posts

    when this occurs again key off engine on put key in the ignition on position. see if it continues to run or stalls.If it runs /idles normal key out and when you put key in to on and it continues to idle normally I would say the ignition switch is the problem .

    also normal operation key out security system should stop any fuel pump operation . If you could repeat this problem hook up a fuel pressure gauge see if you still get fuel pressure with key out. if so must be the ignition switch or in the column rod adjust possible.

    many years ago we would get this type problem it was diesel like run on with key off . cause was high combustion temps and carbon build up in the combustion chamber . we would use a product called regain . this would remove engine deposits caused by additives in the gas.

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