Engine keeps running

[klparker]

Have 2001 Itasca, 220 caterpillar diesel. When I turn the ignition off, the engine keeps running. Any idea why this is happening.

Thanks

[ScottG]

Yea Brett, a turbo diesel can lose a turbo seal and "run away". If it's a big enough leak, it will run well beyond max RPM since the gov. is out of the circuit. Either way, unless you plug the intake, it will run until out of "fuel" and seize.
There are countless videos on Youtube of this happening. Pretty entertaining!

[Trumpet_Player]

RTCastillo wrote:
Use the choke!

What choke?

[wolfe10]

WOW, some really "interesting" replies.

First, suspect this is a Caterpillar 3126 330 HP.

Choke??? on a diesel??

EGR cool down time on a Caterpillar 3126???

Engine is toast because of a (possible) turbo oil seal leak?????

Inline shut-off valve-- never seen one on that chassis, but a VERY good idea on the inlet side of the primary fuel filter.


Let's start with the BASICS:

Are the dash gauges still active/Allison shift pad still illuminated? If so, that points to a failure of the IGNITION SOLENOID or IGNITION SWITCH.

Please give us more facts on exactly what is working as usual vs what is different when you turn off the key.

[gbopp]

naturist wrote:
Yup. You don't want to hear about the OTHER possible failure (because a leaking turbo oil seal usually means the entire engine is toast).

That's scary. If the engine is toast, wouldn't it seize? Or does it lock up when it finally stops running?

[Terryallan]

Usually there is an inline valve to shut off the fuel supply. Could need a flat head / straight slot screwdriver to turn it. As mentioned. diesels don't need electricity to run. It will run until it runs out of fuel.

[Larryect]

I have an egr cool down timer on my Ford 6.0 diesel that keeps it running for a bit after I shut down. Could you have something like that?

[Yosemite_Sam1]

Use the choke!

[magicbus]

Also you might see about opening the vented access panel for the engine and see if there isn't an emergency shutoff switch/valve.

Dave

[naturist]

Yup.

Don't have such an engine myself, but diesel ignition systems have nothing to shut the engine off except (a) a fuel valve/solenoid to shut off the fuel flow and/or (b) an air valve to shut off the flow of air. One or the other isn't working as designed, is most likely. You don't want to hear about the OTHER possible failure (because a leaking turbo oil seal usually means the entire engine is toast).

If you have nearby a 2x6 at least a foot long, and you can place that over the air intake so as to block the air flow, that will shut off the engine. DO NOT ATTEMPT THIS WITH ANYTHING SMALLER OR LESS STIFF THAN THAT 2x6!!!!! A VERY strong vacuum will be formed before the engine dies, and anything less will be sucked right in with catastrophic results.