1982 2.2L gasoline running a second or two after shut off

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John Sutfin
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Car: 1982 Datsun 720, Z22 gasoline

1982 2.2L gasoline running a second or two after shut off

Postby John Sutfin » Fri Jun 10, 2016 1:05 am

I have a 1982 Datsun 720 with a 2.2 Liter gasoline engine. It continues to run rough a few seconds after I turn off the ignition, knocking or dieseling. How can I fix this? :confused:


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lexcrob
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Re: 1982 2.2L gasoline running a second or two after shut off

Postby lexcrob » Fri Jun 10, 2016 1:46 am

I'm not familiar with that engine but id hit the basics.

Overheating could cause that.
Too hot of spark plugs.
Try one step colder plugs.
Read your spark plugs.
Beyond that your looking at an electrical issue possibly the ignition switch hanging or something crazy.

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waynosworld
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Re: 1982 2.2L gasoline running a second or two after shut off

Postby waynosworld » Fri Jun 10, 2016 6:22 pm

John Sutfin wrote:I have a 1982 Datsun 720 with a 2.2 Liter gasoline engine. It continues to run rough a few seconds after I turn off the ignition, knocking or dieseling. How can I fix this? :confused:

The carb is supposed to have a fuel cutoff to stop dieseling.
Maybe you have a Weber?
All I have ever done to stop dieseling is to leave it in gear, turn the key off and let out on the clutch/step on the brake at the same time, no more dieseling and I have been doing it so long I don't even notice doing it anymore.

PaulBjur
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Car: 1981 Datsun 720 kingcab

Re: 1982 2.2L gasoline running a second or two after shut off

Postby PaulBjur » Thu Jun 16, 2016 9:11 pm

Happens all the time in mine, i do exactly what waynosworld said, just let the clutch out in first and hold your foot on the brake whenever you turn it off

ibjman
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Re: 1982 2.2L gasoline running a second or two after shut off

Postby ibjman » Sun Aug 28, 2016 1:09 pm

need to slow the base idle speed. if the engine is idling to fast, it will continue to "run on" when shut down.

As Waynoswold said.....there is an idle step up solenoid to keep the engine idling at the correct speed. When shutting off the engine, this solenoid "drops shut" returning the engine to a very very slow curb idle speed. if these 2 idle speeds are set too high, the engine will diesel and run on when shut off.
Probably nothing wrong with the plugs or cooling system. The idle speeds are set to high.
Regards, Ibj....

flinterman2000
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Re: 1982 2.2L gasoline running a second or two after shut off

Postby flinterman2000 » Thu Oct 06, 2016 6:02 am

I had the same issue with my 8 plug Z20. My issue was the ignition timing. it was advanced too much along with too hot type plugs. feedback from you will help us all.

ElbertThe720
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Re: 1982 2.2L gasoline running a second or two after shut off

Postby ElbertThe720 » Wed Sep 13, 2017 10:50 am

I have same exact truck, 1982 Datsun 720 2.2L Z22S gasonline engine (single cab, short bed) and does the exact same thing.

Previous owner said Smog tech had to adjust the ignition timing and 'mess' with idle a little to pass smog. I suspect what ibjman & flinterman2000 say is the cause of this "hanging-on" after shut down.


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