engine takes time to shut off

[cory_239]

ok well got 87 S15 355 swap got stopping engine problem turn ignition off takes few seconds to die it is like alt is slowly draining before it will die any ideas granted battery relocated to box but only thing that is changed is bat post from alt is now going to battery side of starter would that do it ????

[grim_reaper888]

souds like you have constant power to the ignition somewhere. i had a truck that would only shut off when i opened the door. make sure your distributor wires are loosing power when you turn the key off.

[dn123don]

if you installed an e-fan andwired it directl to the ign. circuit thats your problem.you need a relay

[cory_239]

when ignition is off distributor looses all power right away no hesitation and I also unhooked the fans today and it still does it could it be in the alt itself maybe diode gone in it? It is a high current 114 amp from johndeer tractor everyone should be using these delco alts gm wiring plugs right in but have been using this alt in other aplications and no problems before this but never know i guess!!!

[grim_reaper888]

if your distributor is loosing power immediatly then it should die. motor wont run without spark.

[grim_reaper888]

if you have an old toggle switch try wiring it in between the distributor power wire. then start the truck and flip the switch to see if it dies instantly.

[Melonhead]

Cory, did you set-up to a hotter spark plug? I have seen with a rich running motor and a hot plug that after pulling the distributor 12 volt the engine would continue to run on. The only way I could stop it would be to choke off the air. Changing back to a stock heat range and leaned up the carb and regained control. The other problem that help cause this to occur was the timing was way off. The balancer was set up for 12 o clock and the timing was set from 2 o clock. I found out later that the balancer was from an older motor. Found TDC and found the timing to be straight up. http://www.s10v8.com/images/smilies/icon_biggrin.gif Live and learn

[hollieandgreg]

maybe a hot spot in a combustion chamber, or hot exhaust valves, or carbon that is staying hot enough for ignition.

[Jeffyboy]

My truck was doing it for the reason Melonhead mentioned. When I changed to one colder heat range plug, the problem disappeared.

[Scotty_S-15]

Retarded spark at idle will make the engine "run-on", as well as the "hot-spots" mentioned. And, when the spark is retarded at idle, usually you've gotta add more throttle opening to keep it idling. This too, adds to the "run-on" problem.

............ Back in the early '70s when most engines had retarded spark at idle to somehow help with the emission thing, a lot of factory carbs had solenoids to shut the throttle completely when the ignition was killed. Guess why. http://www.s10v8.com/images/smilies/icon_razz.gif Yeah, "run-on" was a problem.

............. BTW, when I say retarded spark, I mean less than 5 BTDC, not necessarly on the "wrong" side of TDC.http://www.s10v8.com/images/smilies/icon_razz.gif