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

1980-1986 Datsun 720 forums. All 720-specific topics and discussion can be found here.
John Sutfin
Posts: 1
Joined: Fri Jun 10, 2016 12:42 am
Car: 1982 Datsun 720, Z22 gasoline

Post

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:


User avatar
lexcrob
Posts: 559
Joined: Mon Sep 22, 2008 7:38 pm
Car: I get a different ride faster than I could update this.
Location: Clarksville, TN

Post

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.

User avatar
waynosworld
Posts: 232
Joined: Mon Aug 24, 2015 11:10 pm

Post

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
Posts: 2
Joined: Thu Jun 16, 2016 9:01 pm
Car: 1981 Datsun 720 kingcab

Post

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
Posts: 30
Joined: Tue May 12, 2015 5:36 pm
Car: 1986 720 King Cab Z24
Location: Phoenix

Post

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
Posts: 1011
Joined: Mon May 04, 2009 5:32 pm
Car: 2000 Nissan Wingroad, 85 Datsun 720 Pick Up.

Post

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
Posts: 4
Joined: Fri Sep 08, 2017 8:52 pm
Car: 1982 Datsun 720 Lil' Hustler
1975 Chevrolet G10 Van
1991 Harley-Davidson XLH1200

Post

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.


Return to “Datsun 720”