I've had a lot of problems with my car dieseling where it keeps firing even though I've turned it off...is this a carb problem or what? 84 z28 305ho

 

this would be a timing issue... either your base timing is not within specs and or your chain has stretched and needs to be replaced...

 

i had a similar problem where the throttle blade(s) on my carb would stick slightly open after i turned off the ignition, and fuel would get into the still hot cylinders and fire for a couple seconds without spark. (thus the term dieseling)

try cleaning up the linkage. carb cleaner and seafom have helped me more than once

 

the '84 delta 88 i used to have before i got my t/a had that problem. the timing was way off on it. i just shut the car off in gear and it wouldn't diesel.

 

I had the same problem (355 HO 10.3 CR) so what I did was to back out the idle speed adjustment screw all the way so the throttle plates were compleatly closed (double return springs) and added another solonoid (like A/C) to the carb to regulate the idle speed. When I shut off the engine the idle speed solonoid looses power and the throttle plates closes compleatly. NO more dieseling

Auggie

 

Oops, forgot the pic!