can someone tell me the couse of my truck doing this?.

[johny F]

when i turn of my truck(1981 pick up.)it doesnt realy want to shut off all the way..it shakes and acts like it doesnt want to turn off.similar to starting it up.but it finnaly does..just started doing it when i popped off the airfilter to look at it..is it my ignition?maybe carb?or possibly the alternator?i have a feeling im gonna have to change the alternator here soon..but my battery terminals were loose..i dont think that had anything to do with it though..but i could be wrong?..im hoping one of you datsun pros can help a fellow newbie out>?

 

anything helps!

 

i also got a few other question i have to ask.but not on this subject.

thanks guys!

[Zeusimo]

This Happened To Me A While Ago But I Don't Notice It Anymore... :mellow:

[Laecaon]

It kinda of sounds like dieseling to me. This is when the car has been shut off, so no ignition circuit, but the heat and compression still ignites the gas causing the engine to continue to run, like a diesel. I'm not sure on the reasons of dieseling, but it may be too lean/rich or your cam timing is off, though I would lean towards the carb being to lean/rich.

[Laecaon]

To give you a better idea:

http://en.wikipedia.org/wiki/Dieseling

[ggzilla]

Sounds as if someone disabled the "anti-diesel" solenoid on the carburetor. It should be replaced and wired up to solve this problem.

 

Or you could try turning the idle down. Usually at 600 RPM or lower it won't do that. At 750 it will do it. It is normal.

[datzenmike]

.....just started doing it when i popped off the airfilter to look at it

 

Removing the air filter may have disconnected the choke heater wire and the idle cut solenoid wire

 

Check that these wires at the back of the carb are plugged in...

 

 

One wire goes to this black round thing called the choke heater...

 

 

Check your carb with the motor warm, the choke plate should be fully open like this:

 

 

NOT closed or partially closed like this:

 

 

The other wire goes to the idle cut solenoid which stops fuel flow to the idle circuit when the key is turned off. The idle cut solenoid is the hex shaped thing on this carb with a red wire going to it. Your wire won't be blue. Maybe white or blue white.

 

 

 

Also look for any vacuum hoses that may have been pulled loose, and as stated previously, your idle may be set too high which will negate the idle cut solenoid even if it was working.