Engine runs on after turning ignition off?

[showell]

After driving my 2000 4-Runner I turned the key to the off position, only the engine did not turn off? It made like a cranking run-on noise? After turning the ignition on and off several times it finally turned the engine off.

After 10 minutes I went to start it up and it was fine?

Any thoughts on what the problem was and what, if anything, should I do?

 

[Singtoe]

Sounds like bad gas or excessive carbon deposits in the cylinder head.

Try some better gas. If the problem doesn't go away, you will need to clean the engine using Marvelous Mystery Oil or SeaFoam though the PVC vacuum port.

 

[ALBPM]

Are you running Regular or Mid grade gas??? Should be Mid Grade.

 

[Singtoe]

Are you running Regular or Mid grade gas??? Should be Mid Grade.

I run Regular and have Zero issues with runabilty. This is just my opinion but if you are running Midgrade on a normally aspirated 4runner, your wasting your money.

 

[Baja Runner]

I've had that happen to me and it was a vacuum leak, but yours sounds a little different. Id check though..

 

[NTORACN]

Because these engines are fuel injected, if they continue to run after the key is turned off, you would have to have a leaking injector(s).

 

[Baja Runner]

Because these engines are fuel injected, if they continue to run after the key is turned off, you would have to have a leaking injector(s).

hmmm I donno about that one. Try pulling the PCV hose off and turning your engine off, it will diesel for a while.

 

[JohnsD90]

Are you running Regular or Mid grade gas??? Should be Mid Grade.

You should not be running mid grade, you run regular if its N/A and premium if its supercharged!

 

[cfranck1]

Sounds like you have a case of "Engine Dieseling"
The engine keeps running for a short time after being turned off, due to fuel igniting without a spark.
It's named dieseling because it is similar to how a diesel engines operate by firing the fuel without a spark.

You might have a leaky injector and some carbon buildup in the combustion chamber.
Run some Seafoam thru it

 

[sportscarfan]

Another very effective fuel system cleaner not mentioned is Gumout Regane.

I run Regular and have Zero issues with runabilty. This is just my opinion but if you are running Midgrade on a normally aspirated 4runner, your wasting your money.

You should not be running mid grade, you run regular if its N/A and premium if its supercharged!

Regular, mid grade, and premium are ambiguous terms because octane rating varies with geographic location, elevation, etc.

I've noticed low RPM ping (detonation) with "regular" (85 oct. here) so I run "mid grade" or "premium" (87, 91) and the low RPM issue goes away. With the decent torque of the 3.4, I tend to shift early keeping the revs to a minimum around town - a luxury of the 5-speed.

Also helpful off road in very low speed situations.

 

[YotaZach85]

Regular, mid grade, and premium are ambiguous terms because octane rating varies with geographic location, elevation, etc.

I've noticed low RPM ping (detonation) with "regular" (85 oct. here) so I run "mid grade" or "premium" (87, 91) and the low RPM issue goes away. With the decent torque of the 3.4, I tend to shift early keeping the revs to a minimum around town - a luxury of the 5-speed.

Also helpful off road in very low speed situations.

I never even thought of that, regular to me is 87 and premium is 93....that's a very good point.

 

[ALBPM]

Mid grade here is 87. Regular is 85 and Premium is 91-92.
My 02 runs better on Mid grade.

 

[Singtoe]

Mid grade here is 87. Regular is 85 and Premium is 91-92.
My 02 runs better on Mid grade.

There is a pipeline that runs from TX to NY and it deposits fuel into Tank Farms all long the east coast. They only pump two types of gas Regular and Super.

Mid grade gets mixed at the fuel depot or at the gas station.

We even have gas stations here that sell 103 octane.


That is besides the point. The OP has other issues besides low octane gas like dirty gas or a dirty combustion chamber.

 

[hodgeae10]

Similar experience - still think it's bad gas?

After driving my 2000 4-Runner I turned the key to the off position, only the engine did not turn off? It made like a cranking run-on noise? After turning the ignition on and off several times it finally turned the engine off.

After 10 minutes I went to start it up and it was fine?

Any thoughts on what the problem was and what, if anything, should I do?

Hi there,

I had a similar experience to Showell's this weekend. I have a 1999 V6 SR5 4Runner. Stopped at camp in evening after driving most of the day. After about 30mins started it up and engine was making very strange noise. Drove a little then stopped, turned off, but the truck sounded like it was still running! Didn't know what to do so I restarted it immediately, smelled some kind of a burning smell, but then it ran fine.
Next day, put Gumout fuel injector cleaner in with 88 gas (usually use 87; never 85), drove the 100 miles back home and it seems totally normal.
Should I be worried or you all still think bad gas?

Thanks!