In my typical style I have another boggler:

My datsun with the weber dfav 32/36 has this cute habit of backfiring out the exhaust when I park the car and turn it off.

technically a backfire is fire out of the carburetor an afterfire is fire out of the exhaust.

if an engine runs lean it backfires, if shes rich she afterfires (typically)

what causes that?

I've heard it could be:


or is it related to the middle exhaust manifold stud being missing letting pure o2 leak into the exhaust?

or is caused by the air leak at the bottom of my carb?

is it likeley that i'm too rich at idle/everywhere or is the catylitic converter just lighting off excess vapor? should i let the car idle for a minute or 2 before shutting it down? I know it won't backfire any worse...

or is it something else?

I'm likely to buy a different weber with the anti-dieseling solenoid ( that would fix it??? )

well, i leaned it out and now it backfires ( out the carb )
which makes the neighbors happier i suppose.

i suppose i need to fix the vacuum leaks...

don't try putting a weber on unless you don't mind these kinds of adventures I suppose.

it always runs good, it's just got so much personality now.

oh another thing... seems to like to stall when braking hard, not because the vacuum booster stealing vacuum ( or I think not ) cuz i can pump the brake pedal al day at a stop and the idle changes less than it does on my stockish 83 sunny E16. Yes I have the fuel bowl in the front of the carb.