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Thread: 87 GM turns off randomly.

  1. #1
    GMN Regular slack's Avatar
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    Question 87 GM turns off randomly.

    Hi All,

    I've been tracking down this issue with my GM where it will randomly shut off. Dash lights come on when this happens. It also starts back up fine.

    Originally, it just happened sometimes when first reversing out of a spot but it's progressed where it seems to happen on fast turns and even seemingly randomly.

    Earlier in the summer I replaced my IAC with the one from my CV which seemed to fix the issue where it would randomly die idling. This past weekend I swapped over my ignition coil and ECT from the CV as well just to see if it made any difference as they only took a few minutes to swap in.

    No difference there but at least now I know the ones on the GM were good for future spare parts.

    While starting the car during testing the swapped parts, I noticed that the ignition key cylinder seemed extra "touchy". Like, once it started, if you tapped it towards you lightly the car would immediately shut off like you turned the key off.

    My only guess is that it was already worn when I bought the car a year ago but finally hit the point of being worn enough to start causing problems now.

    So, my question is... after this wall of text ...

    Should I pick up a whole new one: https://www.rockauto.com/en/moreinfo...199448&pt=4700

    Or is it possible to repair the one I have?

    I didn't take the one from the CV so I don't have a spare on hand. Also, any pointers on how to remove it would be greatly appreciated.

    Thanks!


    '78 LTD | '87 Grand Marquis | '89 Crown Vic (RIP) | '91 Grand Marquis (RIP) | '94 Town Car (RIP) | '97 Town Car (RIP)

  2. #2
    all the CFI are belong to me
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    Your problem is very unlikely to be the lock cylinder, and very likely to be the ignition switch itself, inside the coloumn trim.

    If you remove the column trim you may find the switch is visually falling apart/splitting into two. This is common and causes your symptom.

    If it is splitting apart, you may be able to resolve it (lasting anywhere from 5 minutes to forever) by re-staking the casing of the switch closed again. You'll have to put eyes on it to evaluate.

    Current drivers: 84 TC | 85 CS
    Panthers, Parked: 83 GM 2dr | 86 GM | 88 TC | 91 GM
    Not Panthers: 85 Ranger | Ranger trailer | 05 Focus
    RIP: 97 CV | 83 TC | 04 Focus | Junkyards

  3. #3
    GMN Regular slack's Avatar
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    Quote Originally Posted by kishy View Post
    Your problem is very unlikely to be the lock cylinder, and very likely to be the ignition switch itself, inside the coloumn trim.

    If you remove the column trim you may find the switch is visually falling apart/splitting into two. This is common and causes your symptom.

    If it is splitting apart, you may be able to resolve it (lasting anywhere from 5 minutes to forever) by re-staking the casing of the switch closed again. You'll have to put eyes on it to evaluate.
    Good to know! Thanks! I hopefully might have some time tonight after work to take a look and see.

    is this what the switch looks like? https://www.rockauto.com/en/moreinfo...199448&pt=4700


    '78 LTD | '87 Grand Marquis | '89 Crown Vic (RIP) | '91 Grand Marquis (RIP) | '94 Town Car (RIP) | '97 Town Car (RIP)

  4. #4
    all the CFI are belong to me
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    Quote Originally Posted by slack View Post
    Good to know! Thanks! I hopefully might have some time tonight after work to take a look and see.

    is this what the switch looks like? https://www.rockauto.com/en/moreinfo...199448&pt=4700
    Correct, that's it. You can see where the plastic and metal halves meet together, there are little metal legs that clamp them together. One of the ways they can fail is that they tend to spread apart over time and let the switch open up, which causes it to still work but make bad contact for a while before totally stopping working.

    Current drivers: 84 TC | 85 CS
    Panthers, Parked: 83 GM 2dr | 86 GM | 88 TC | 91 GM
    Not Panthers: 85 Ranger | Ranger trailer | 05 Focus
    RIP: 97 CV | 83 TC | 04 Focus | Junkyards

  5. #5
    GMN Regular slack's Avatar
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    Awesome! Thanks again. I hopefully might even have one of these floating around my garage from my CV if its easy to get to.

    I'll update later tonight with what I found.


    '78 LTD | '87 Grand Marquis | '89 Crown Vic (RIP) | '91 Grand Marquis (RIP) | '94 Town Car (RIP) | '97 Town Car (RIP)

  6. #6
    Still Wrenchin'! friskyfrankie's Avatar
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    +1 on the ignition switch. If you can afford a new one I would rather do that than fix the current one (check for evidence of burnt connectors in it or along the case). I then to use Motorcraft parts but that is up to you and your wallet.
    What I Own: 1993 Mercury Grand Marquis GS
    What I Help Maintain: 1996 CV / 1988 CV / 1988 Tempo

  7. #7
    I'm an air-conditioned gypsy gadget73's Avatar
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    sometimes for a really temp fix you can zip tie it together if the contacts are coming loose but for the 15 bucks or whstever they cost its not worth it.

    simple to change, remove the lower steering column shroud and its right there under the shift lever. Only possibly-hard thing is the screws. If its normal security Torx, easy. if its the older headless ones, they sort of suck. You can either Dremel a slot in there to try and use a screwdriver, or the better way is to use a stud extractor or a rounded-off bolt extractor if you have one. The kind that look like an inverted EZ Out. Tap it on, they spin right out. The switch should come with a set of security torx bits to replace the dumb style screws.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

  8. #8
    GMN Regular slack's Avatar
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    Thanks everyone. You guys were spot on. The ignition switch is definitely on its way out.

    Here you can see the left half is popping out:


    Here's a video of me pressing on it to turn the car on/off. Also, at the beginning you can see how touchy the ignition cylinder is though it might just be transferring vibrations to the really flakey switch.


    It still has the original security bolts on it that Gadget mentioned. Thankfully I have a set of bits around the house somewhere. I bought them when I was repairing the power supply for one of my IBM XTs (just need to find it). I don't remember taking this bit from my CV so looks like I'll be buying a new one to replace it.


    '78 LTD | '87 Grand Marquis | '89 Crown Vic (RIP) | '91 Grand Marquis (RIP) | '94 Town Car (RIP) | '97 Town Car (RIP)

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    GMN Regular slack's Avatar
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    Just wanted to update now that the new switch has been in a bit.
    That completely fixed the problem. No issues with the key cylinder either.

    The switch I bought didn't come with the new bolts so I just reused the old ones. Also, the new switch comes with a clip on it. I thought "Oh.. I don't remember mine having that." and fiddled with it causing it to pop off. Then I read the instructions where it said at the top: "DO NOT REMOVE CLIP UNTIL SWITCH IS INSTALLED AND ADJUSTED".

    Whoops. Anyway, it didn't seem to make a difference. I guess it keeps the sliding plate that the little nub fits into in the KOEO position so you can't accidentally force it while not lined up.

    Thanks again everyone!


    '78 LTD | '87 Grand Marquis | '89 Crown Vic (RIP) | '91 Grand Marquis (RIP) | '94 Town Car (RIP) | '97 Town Car (RIP)

  10. #10
    I'm an air-conditioned gypsy gadget73's Avatar
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    I think I actually didn't get new screws with the Continental either. I didn't re-use them but I may have gone to the hardware store and gotten some phillips head or something that was the correct thread.

    86 Lincoln Town Car (Galactica).
    5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

    91 Lincoln Mark VII LSC SE, triple black (Timewarp) - poly front bushings, KYB struts and shocks, Holley SystemMax1 lower intake, SilverFox AOD valve body,

    1984 Lincoln Continental TurboDiesel - rolls coal

    Quote Originally Posted by phayzer5 View Post
    I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

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