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Old 10-10-2009, 08:50 PM   #1
dan42
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truck runs when I turn the key off -

I just replaced the tumblers 6 months ago, but this afternoon I tried to turn the key of and it kept running. is the switch bad, or is it possible I lost a ground, because I am in the process of taking my bed out? I'm not crazy about having to disconnect the battery to turn the truck off every time.
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Old 10-10-2009, 09:29 PM   #2
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Re: truck runs when I turn the key off -

I just took the ground side of the battery off and it kept running. I've never done that before (there was no reason too) but does anyone know if that's normal?
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Old 10-10-2009, 09:38 PM   #3
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Re: truck runs when I turn the key off -

The switch could be bad or it could be a short. I don't think it has anything to do with the bed. Does it have an HEI distributor?

It's probably running off of the Alt.

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Old 10-10-2009, 10:13 PM   #4
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Re: truck runs when I turn the key off -

I had a 71 burb, and I know this sounds crazy. Would keep running with the key off if the radio was turned off. Turn the radio on and the key off, engine would die. Never did figure that one out.
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Old 10-10-2009, 10:23 PM   #5
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Re: truck runs when I turn the key off -

My truck and cars did that also after installing msd boxes. There is a diode you can install in the alt wiring so it stops backfeeding voltage.
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Old 10-10-2009, 11:17 PM   #6
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Re: truck runs when I turn the key off -

It does have a HEI, but it's been on the truck for over a year with no problems until today. I think I'll start at replacing the switch.
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Old 10-10-2009, 11:38 PM   #7
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Re: truck runs when I turn the key off -

do you have an electric fan by chance?
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Old 10-11-2009, 02:37 AM   #8
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Re: truck runs when I turn the key off -

No electric fan. I tapped the switch a couple of times, thinking maybe something stuck, but nothing. I do have an amp and radio installed but it has worked fine for maybe 3 or 4 months with it until now.
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Old 10-11-2009, 05:27 AM   #9
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Re: truck runs when I turn the key off -

Unhook the wiring hartness from the key switch and see if its still running.
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Old 10-11-2009, 06:22 AM   #10
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Re: truck runs when I turn the key off -

Quote:
Originally Posted by dan42 View Post
I just replaced the tumblers 6 months ago, but this afternoon I tried to turn the key of and it kept running. is the switch bad, or is it possible I lost a ground, because I am in the process of taking my bed out? I'm not crazy about having to disconnect the battery to turn the truck off every time.
I would say the ingnition switch is bad the contacts inside prolly broke the easiest way to shut the truck off is to pull your main ignition lead off of the distributor but that will be a pain to do that all the time good luck
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Old 10-11-2009, 08:00 AM   #11
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Re: truck runs when I turn the key off -

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After reading through this again I think Pont406 might be on to something. Try unhooking the wiring to the alternator, start it up and see if it will shut off. Make sure the alt. wires aren't touching anything metal.

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Old 10-11-2009, 08:22 AM   #12
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Re: truck runs when I turn the key off -

It's just how great these trucks are. Nothing can kill them. They run no matter what... Even when you try to kill them, they keep running... You can't even turn these bad boys off.
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Old 10-11-2009, 09:27 AM   #13
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Re: truck runs when I turn the key off -

Quote:
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It's just how great these trucks are. Nothing can kill them. They run no matter what... Even when you try to kill them, they keep running... You can't even turn these bad boys off.
funny chit
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Old 10-15-2009, 11:24 PM   #14
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Re: truck runs when I turn the key off -

O.K. - I pulled the alternator wire off, and tried to turn off the truck - no dice. I have now replaced the ignition switch with a new one from Brother's, and it still doesn't shut off. Does anyone have any good ideas??
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Old 10-15-2009, 11:43 PM   #15
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Re: truck runs when I turn the key off -

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Is there only one wire that plugs into the HEI?

Where does the hot wire to the HEI come from?

Unplug the hot wire from the Distributor and see if it is hot with the key off. If it is you have it hooked to the wrong source.

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Old 10-16-2009, 12:05 AM   #16
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Re: truck runs when I turn the key off -

I'm real interested to see the culprit to this gremlin.

Since years ago, before I began restoring my burb I had the same thing happen to me. Just so happens I was stuck up there in your neck of the woods!

Luckily I was up at my Mom's house, and I had a local Napa store near by.

The only way I could get mine to stop running was to through a rag on top of the carb to choke out! I had disco'd everything as well, and it would just keep running.

There was a bigger problem though. In my case I could not get the truck to go above 3K RPM under load, if I did it would sputter and backfire... Long story short, I ended up going home with a borrowed car. Once there I grabbed a engine I had, and trucked it up there. Had the local Chevron swap out the motors, then drove it home!

Took my 327 to the shop for a diagnosis, and apparently all of the rings washed out. Half were broken, and the others were pollished and the edges rounded off. I would have never believed it, but the machinist showed it all to me. He said that I must have over heated or leaned it out?
It was a hot day, and I did hot dog it up highway 101 up the steep grades but I know I didn't overheat...

One of my all time mystery's I have had in my burbs past.
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Old 10-16-2009, 12:18 AM   #17
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Re: truck runs when I turn the key off -

Quote:
Originally Posted by LockDoc View Post
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Is there only one wire that plugs into the HEI?

Where does the hot wire to the HEI come from?

Unplug the hot wire from the Distributor and see if it is hot with the key off. If it is you have it hooked to the wrong source.

LockDoc
I will check that out - but why would it have run for basically the last year, and I haven't changed anything?
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Old 10-16-2009, 12:43 AM   #18
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Re: truck runs when I turn the key off -

Mine did that when there was a problem with the alternator wiring. I would try another new switch, i had a hard time with my wipers last year becuase i got a bad switch from brothers. I replaced the switch then the motor and then found out my new switch was bad.
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Old 10-16-2009, 01:35 AM   #19
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Re: truck runs when I turn the key off -

I would go with locdocs recomendation to test with key off engine off if there is power at the batt terminal on the hei (If there is no power it suggests feed back on the alternator wiring brown wire) If there is power with koeo it a wiring or switch issue.
Do you have external or internal voltage reg?
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Old 10-16-2009, 09:37 AM   #20
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Re: truck runs when I turn the key off -

Internal. 1 wire alternator. It's actually the second switch I got from Brother's - the first I couldn't even get the tumbler installed into. This one had a big chunk of plastic on the bottom of it I had to fish out before I could install it.
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Old 10-16-2009, 10:02 AM   #21
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Re: truck runs when I turn the key off -

I'd be a little more concerned if it starts itself up, remember Christine?
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Old 10-16-2009, 10:24 AM   #22
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Re: truck runs when I turn the key off -

Quote:
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I'd be a little more concerned if it starts itself up, remember Christine?
Or how about Killdozer?

I guess I'm old.

Back to the original question. Apparently you didn't change anything that might have caused the problem, so that means something either wore out or broke. You've tried the key switch and the alternator, so the only other thing I can think of is the starter solenoid.

Your solenoid has two small posts marked "S" and "R". The starter switch should be connected to the "S" post. The original coil may have been connected to the "R" post. If the HEI is connected to that post, carbon arcing may be causing it to short and provide juice to the HEI even with the ignition switch off.

Kind of a long shot, but it's the only thing I can think of that you haven't tried.
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Old 10-16-2009, 10:34 AM   #23
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Re: truck runs when I turn the key off -

I had this very same problem on my truck soon after I got it. I first changed the ignition switch as it had one burnt terminal, but no luck. Two days before this happened I had made the one wire altenator swap and had crossed some wires on the voltage regulator, no problems since I corrected those wires.
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Old 10-16-2009, 12:47 PM   #24
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Re: truck runs when I turn the key off -

Truckster, thank you - I'll try that and see if it works. Whatever the problem is , I'll find it, and let you guys know for future reference.
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