Stalling after shifting, while slowing to idle in gear.

[sik8v at netscape.net (rhys)]

you truly are god.

i'll play around a bit and get back to you guys for sure.

Thanks,
Rhys

amalventano@sc.rr.com wrote:

>>Alright, this has gone on lone enough.
>>
>>The  car ('84 rocco, 1.8 CIS) just dies after shifting. It used to be
>>    
>>
>
>reposted from my post from last september:
>
>---------------------------------------------
>
>The rieger does the same exact thing:
>    our cars have an idle fuel cutout. if the throttle is at the idle
>position,
>it closes the switch on the throttle body. if the idle switch is closed and
>rpm
>  
>
>>~1600, this results in the jetronic box applying ~-50ma to the DPR until
>>    
>>
>rpm
>drops below ~1400 rpm. This lets the engine coast down with no fuel (as
>opposed
>to the fuel injection attempting to supply correct fuel during a coast).
>    as a side note, there is a time delay. the ecu must see the idle switch
>closed for >1/4 second in order for it to start the idle kickdown process.
>
>the reason we get our stall is a combination of any of the following:
>
>- dirty idle contact, resulting in longer than 1/4 sec lag for ecu to see
>the
>switch closed (switch debouncing is accomplished by a r/c circuit in the
>jetronic box), resulting in the kickdown occuring right at 1400 rpm or
>slightly
>below, possibly resulting in a stall if you get it just right.
>- sluggish/clogged fuel system, resulting in a lag as the DPR attempts to
>get
>back to normal control pressure (<1400 rpm). if it cant get pressure back
>quick
>enough, you stall.
>- vacuum leaks (may not be enough to mess with idle, but can be enough to
>cause
>a stall in this kickdown condition).
>- tuning: the kickdown circuit recovers to the standard +5 to +10 ma DPR
>current
>range. if you adjusted/tweaked your DPR current out of this range, your
>fuel/air
>will be out of whack immediately following the kickdown. this may be enough
>to
>cause a stall.
>- idle speed set screw adjusted too low. if the ISV is already at near max
>open
>dwell during a normal idle, it cant open any further to correct for the
>downward
>swing during a kickdown, meaning its harder for the system to recover a low
>idle
>speed, and you stall.
>
>    and finally, the reason the problem goes away when the a/c is on: idle
>kickdown is disabled with the a/c on to prevent compressor loading from
>stalling
>the engine during a kickdown event.
>
>    I plan on messing with these things one at a time until i nail it, but i
>am
>fairly certain that its a combination of the above thats causing it right
>now. i
>have a feeling simply opening the idle speed set screw a bit will fix the
>problem.
>
>HTH
>Al
>
>
>  
>

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