engine stalls on hard braking

this pertains to a 1998 honda civic LX, at, ac, 163000 miles:
recently during the last few months whenever i'm travelling at between
20 and 40 mph and i've had to brake very suddenly and very hard, the
engine stalls as soon as the car comes to complete stop. never used to
do that before. engine starts up w/o any difficulty afterwards. a/c
is NOT on when this happens. engine does NOT do this when i brake
normally, i.e., non-panic stop.
any ideas on what's causing this and what components to check? any
advice would be greatly appreciated .....
tia.

 

have you had the ignition switch recalled?

 

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Are you sure your CHECK ENGINE light is functioning, and are there any
CODES stored?

'Curly'

 

no, haven't had any recall on the ignition switch

 

'check engine' light comes on fine when you go to start the engine and
then it goes out (normal operation). no codes are stored. 'check
engine' light does not come as part of this problem except after the
engine has stalled (and the other lights are on as well)

 

ok. there was a recall. if your ignition is defective, hard braking
could be moving your key bunch about and upsetting an about-to-fail
switch. go to the dealer and get the free recalled switch fitted - the
problem should go away.

 

This could be a problem with the brake power booster having an air
leak. Does the engine stall if you apply the brakes hard while
stationary?

 

ok! thanks. i'll check out the other items on this thread as well,
just on g.p., and take myself down to the dealer. thanks.

 

i'll check it out his weekend. thanks.

 

Wonder if your dashpot, or throttle control is functioning right...
Normally, the throttle is held open a bit for say appx 3 seconds or
so before it goes to idle. The purpose is to prevent stalling on hard
stops due to the throttle cutting off too quick. You should be able to
get an idea if it's working by goosing the throttle up to 3k or so, and

quickly releasing. It should take about 3 seconds or so to totally cut
back to idle. If it cuts back almost instantly, I'd check the
idle/dashpot
controls. Just thought I'd mention this being as no one has yet..
MK

 

not on a fuel injected car with electronic idle air control. and with
carburetted cars, it depends on the design - many didn't have dash pots
at all.

btw, the reason the motor takes time to drop to idle speed is because of
the momentum of the rotating crankshaft, flywheel [etc.] mass - it's not
a function of carburetion.

 

My 88 Tercel manual said that the throttle was held open to burn off
fuel spray remaining in the intake manifold after the throttle suddenly
closes. It was a CA and federal emissions component. It might have a
different use in fuel injected cars, though.

The idle screw is usually what prevents the stall. Even a modern car
needs it set properly to avoid stalls.

 

not on a fuel injected car with electronic idle air control. and with
carburetted cars, it depends on the design - many didn't have dash pots
at all.

btw, the reason the motor takes time to drop to idle speed is because of
the momentum of the rotating crankshaft, flywheel [etc.] mass - it's not
a function of carburetion.

 

I was thinking the idle air valve would control that. But I couldn't
remember if it was computer driven, or used a dashpot for a slow
release.

and with

My 89 accord with a carb does. Has a section in the manual covering
the "dashpot system". But it seems to be part of the throttle
controller.

Well, yes, the flywheel, etc adds to it, but in the case of my car,
it's also a function of the carb. The dashpot keeps the throttle
controller
arm from fully extending too fast. In checking the manual, they state
the
proper time is 1-3 seconds. They say if it's less than 1 second, or
more
than 3 seconds, to inspect the throttle control valve, vacuum, etc.
I was thinking even the EFI cars had some type of slow throttle return,
even though it's probably using a different method to achieve it. I
was
thinking it was controlled by the computer via the IAC...? Maybe not
though..
The "puter" manual I'm looking at now doesn't cover the EFI version,
and
my crappy haynes manual is out in the car.. I don't think it's normal
for
any of them to return to idle in less than 1 second. In the case of
mine,
they say it will, if the throttle controller/dashpot is not working
right. So the
flywheel inertia on it's own must not last too long.. BTW, the 1-3
second
return on mine is from 3500 rpm maintained for 2-3 seconds, and
suddenly
released.
MK

 

got the switch replaced, checked (i did) all vacuum lines, + the idle
air control valve still having the same problem

 

no, it does not stall when brakes are applied hard when car is
stationary.

 

hmmm. does it stagger to a halt with the motor fighting against the
brakes, or does the motor smoothly cut out? if the lockout clutch on
the transmission is not releasing quickly enough, that could stall it.
also check the idle speed is set correctly. basically, [with a fully
warm engine] disconnect the iacv and adjust the idle screw to achieve
750 rpm. iacv's don't adjust too quickly, so if you stop too fast,
maybe it's go too far to adjust and can't get there fast enough? [guessing]

other than that, look for an electrical problem. is there any
mechanical componentry floating about or loose connections under the
dash that could be disrupting power to the ecu or ignition? any bad
stereo installations?