car spuders when shut off

[87AccordLXsdn]

when i shut the car off, it spuders for about 3 seconds, sometimes longer, and then revs up real hard and finally shuts off. wtf? its really embarassing when other ppl are around. this happen to anyone else?? anyone know how to fix it? by the way its a weber.

[ghettogeddy]

wheal i belive they call it desinling but im not sure how to fix it my car dose the same thing just not all the time but some did tell me not to let it do that so if u have a stick put in gear put ur foot on the brake and let the clutch out cause those few secends could be really bad for the motor

[88Accord-DX]

Most causes of dieseling is from carbon buildup in the cylinders that continue to burn fuel inside the cylinders like a glow plug, especially on carbureted engines.

High idle causes dieseling, incorrect timing, & some cases low octane fuel.

[HondaBoy]

i found mine to do that also a while back. i reset the timing and that fixed it. its also happened because of a vacuum leak on my carb when a line was disconnected. and its called dieseling,

[87 Acc]

It use to happen to me once and awhile. But after I did the vacuum up grade it has completely stopped.

[A20A1]

Yeah a vacuum leak can cause your idle diaphragm to go out of wack and raise the idle more by opening the throttle. Opening the throttle causes your vacuum to drop off further which opens the throttle even more.

Vacuum keeps the throttle controller / idle diaphragm in check... it's also possible you have set the idle screw too high to compensate for a vacuum leak, which just makes the problem worse. Or you can try and fix the high idle by lowering the idle screw, but then the car will tend to stall and will have a hard time starting in some cases.

So the best bet is to find what is causing your vacuum problem and fix it... then go back and set the idle. You may want to lower the idle for the time being as much as you can.

[Beaver]

My car does this too! I don't think I have a vacuum leack though so that can't be it, all my hoses are new. I find it occurs when I drive the car and it's not fully warmed up when I shut it off.

[A20A1]

There are many places vacuum can leak from.
- Gaskets; intake manifold and carburetor
- Diaphragms
- O-Rings
- Vacuum lines
- Malfunctionng Thermovalves, or thermovalves that fail to recieve coolant because of a low coolant level or something wrong with the water pump or thermostat.

[Beaver]

Man... I don't even know where to start then. Maybe I will start trying to narrow it down after I put my civic box shortram on.

[ghettogeddy]

It use to happen to me once and awhile. But after I did the vacuum up grade it has completely stopped.
what is this upgrad u speak of is it the removal of or is there actually an upgrade kit

[A20A1]

Vacuum removal... the reasoning behind which was to get rid of all the variables that could make the car act funny... strip the carb down to basic parts and go from there.

[87 Acc]

this is the link for the vacuum up grade http://www.3geez.com/forum/showthread.php?t=11067

[A18A]

err that vacuum upgrade is 2 advanced for my poor little brain