Van just likes to run!

So I got this issue with my 67 G10 where she continues to run a few seconds after the key is shut off.  Not a big deal I guess cause she does shut off after a few seconds. Weird huh?  Never seen anything like it. I started by changing the coil thinking it might be some how holding a charge. No change. Changed the ignition switch, still wanted to run a few seconds. Next I changed out the coil and distributor with a new HEI distributor and she still wants to run a few seconds after the key is turned off.  What could possible hold voltage in this simple primitive electrical system that could cause such a thing?  Man....  Anybody ever seen this gremlin before?  Any help catching him would be deeply appreciated.   Thanks.

when my timing was too retarded my van liked to diesel...could be a bunch of carbon on top of the piston acting like a glow plug too...

Do you have one of those 3rd Gen internal regulator alternators on it?

run a test,,,,unplug the voltage regulator and see if anything changes if you got the stock system,,,,

Your idea makes since. It's not like it's dieseling tho. Not rough or anything anyway. It's like you didn't turn the switch off yet.  Still running smooth.  Although the electric radiator fan turns off immediately when the key is cut off.  And then she just dies like you cut her off after a couple seconds. Hmmmm.

Donivan - It has a newer one wire alternator installed. No voltage regulator. Could that be the problem. It just has the one wire to the battery tho.

Thanks Guys. I'll pull the plug out of the side of the alternator and see what happens as soon as I can. Really not sure how this could cause it though as this is not switched through the ignition. Hmmmmm.

Unplug the fan for a test too,,,,,,everything is connected together on the output side of the ignition switch,,,,as well as the distributor,,,,,,,so if anything is putting out a voltage signal,,,it feeds to the distributor and you get spark,,,,,and stuff turning kind of sends out a signal before it stops,,,,,,so unplug stuff that is turning for a test,,,,,just to see if the distributor is not shutting down quickly,,,,I would make up a jumper on the feed wire going into the distributor so you could just unplug the power to the distributor and see if the engine stops,,,,to eliminate if you have an electrical problem,,,,,if it dont, then we go looking for a mechanical problem of what we call DIESELING

so do you have a 1 wire hot rod alternator or a converted 3rd Gen one with a 2 wire plug on the side that turns it on and senses the voltage,,,,,,,that #1 wire requires a resistor or it feeds back to the output side of the ignition switch,,,,,

have an electric fan on mine, when I turn the key off, the spinning fan allows enough current to run the engine, it dies as soon as the fan stops spinning, only a second or two.

I'm out of town this week but will dig into it as soon as I get home. I'll take a picture of the hook up on the alternator and post it. Man.... the fan theory sounds like that may be the culprit because I don't think it does it until the engine has warmed up to the temp that the fan would be on. I hope that's it. If so I guess an inline diode would probably cure it huh?
Thanks so much ya'll. I'll post my findings soon.

Thanks everyone for your continuous support. Looks like it is the fan that keeps the motor running after shutting the key off. If the van is cold, it shuts off instantly. After the engine is warmed up to the point of the fan needing to run, when I shut the key off she will continue to run until the fan stops. I tried to wire my alternator like the diagram and when I went to turn the engine off, it would not stop with the key turned off. I had to disconnect the plug from the HEI distributor to shut her down. The way mine is wired is the white wire (terminal 1) is run to the battery and the red wire (terminal 2) is jumped to terminal 3. Seems to work like that but the problem I'm having now is the battery drains in a day or two if the van is not run. Is this what I need? Will this cure my battery drain? Thanks.

http://www.ebay.com/itm/Anti-Feed-Back-Diode-Harness-10SI-12SI-15SI-27SI-Delco-Alternator-Regulator-Lead/152043261434?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D38530%26meid%3Db1bd3a58c3ba4494aec7cf525079b7c0%26pid%3D100033%26rk%3D7%26rkt%3D8%26sd%3D182354565378

Damnit boy! Got the battery charged up and checked it again and it's not charging. Gonna attempt to run new wire and wire up the alternator like your diagram. Hopefully that will cure it. I let ya know what happens.

#1 needs to be hooked to the ignition switch and needs to be turned on and off with the key,,,you might of burned up the regulator by leaving it hooked to the battery all the time, that plug looks likes a way hook up a 3rd Gen alternator the RIGHT way,,,,,,if the alternator does not charge anymore and you are not brave enough to open up the alternator and change the regulator,,,,,I think Autozone sells those alternators for about $29,,,,,,,

Thanks Don. Hope to have some time to spend on it next week. I'm going to wire it up like you posted and see what happens. I might have cooked the regulator as it was charging prior to setting for a couple days. I appreciate your expertise. I'll keep ya posted. UDaMan!

you dont really need a wire on #1 to test it,,,,,,,all it wants is juice for a second to turn on the regulator after the engine is running,,,,,as long as you got #2 hooked to #3  and going to the battery,,,,,,I take a test light when the engine is running,,,,,hook it to #3, and touch it to #1   for a second to wake up the regulator so it can tell the alternator to start charging,,,,,then you go figure out how to hook #1 to the ignition switch with a diode, resistor or using the idiot light wire, which was the #4 brown wire to the old voltage regulator on the back of the doghouse,,,,,

That wire should be hooked to the idiot light for idiot light operation and exciting the alternator. As I understand it, if this is wired w/o a bulb, resistor or diode it can cause the run on problem. A resistor can be wired to either side of the bulb to ensure the alternator doesn't stop charging if the bulb burns out. But it is clear when the bulb is bad b/c it won't come on when the key is turned to run.

Success! I traced all the wiring, wired up a new alternator like shown in the picture with the addition of the diode harness, and she's charging and holding charge now. I even have a working idiot light now. I still have the issue of it continuing to run until the electric fan stops turning but not a big deal. Thanks to all for your help. If your ever passing through NC, stop in and Ill buy ya a cold beer.

is your cooling fan run through a relay?

My fan is run through a thermostat controller but not control voltage relay. Should it be?

if you make the controller operate a relay to turn on your fan
it should stop the back feed of power to your ignition system.
the wire from your controller to the fan should go to the low amp
side of relay or term# 85 and #86 should be a ground, run battery
power to #30 and the fan to # 87, this should stop the running on
of your engine with the fan running, hope this helps

Sounds good. Were do I purchase this relay? Is it an ebay item or can I get one at a parts store? Thanks for your help.

any parts store should carry these relays just a
30 amp relay with 4 or 5 terminals, if it is a 5 terminal
just ignore terminal # 87a

orielly part #r4176 will get the job done

Thanks brutha. I'll pick one up tomorrow. I'll let ya know how she pans out.

Yes I have seen this before.

your electric cooling fans are acting like generators. You can do the relay thing or simply put a diode into the fan power wire. Most cooling fan providers offer the diode.
m1D