the bleed screw is duty cycle, CALIBRATION. spec is 50%
and its 2nd job, is recalibrate if you have minor air leaks. in the induction, (SAY tv BORE WEAR afte 300k miles)
and 3rd is a older tired, engine (weaker) re calibration. (olders engine have weaker vacuum)
the ISC can in fact compensate for leaks, or any weak engine , hands off. that is its job. so long as , ISC not jammed, or huge leaks.(or huge lean)
but you need to keep the duty at 50% hot. (when at 50% 800rpm locks in, in ECU SERVO mode, and is hard coded that spec.)
so, if you unscrew the bleed and like magic the RPM leaps to 800 , that means the ISC just woke up. (works both ways, too fast RPM screw it in)
keep in mind 2 facts.
the ISC can not correct huge leaks. (it can not close more that 100% ) so CANT work with huge leaks, (case in point ruptured brake booster diaphragm)
and the opposite of that is true. if say the bleed is closed 100% the ISC (ecu is brain of that) MAY NOT BE ABLE TO OPEN ENOUGH TO GET 800 RPM.
[i]lazy fingers caps look sorry.[/i
your case is rare here, low RPM. (discounting the huge EGR stuck open issues) most are too high RPM issues.
one easy way to fix this, (assumes nothing major bad)
is to see the DC voltage on the ISC pins to 7vdc running, by turning the bleed screw .
my guess is it will read 12 to 14v now, (wrong)
and you open the bleed screw and as you do the voltage drops. and ISC wakes up.
but keep turning until 7vdc is hit, (some older meters cant do this, too slow , old meters or dirt cheap ones)
suzuki uses a tool you can;t buy. it uses a current mode duty meter, its not made.
but there 3 tools that do work
most nice DMM on DCV volts 20vdc scale.
nicer meters with DUTY mode (on dial)
and all scopes ever made can do 200 HZ isc signal. all can
2 other things cause rpm low and isc dead.
are
lean AFR (will bogs like crazy)
or spark timing set way retarded....
nut shell:
connect meter.
turn screw for 7v "bleed"
800 happens under software (firm) in ECU, the brain is programmed to 800 hot, (1000 under p/s overload or A/C on) hot.
its unstoppable this once it works,
der bleedn splunken
http://www.fixkick.com/fresh-air/Slide_S...ge_32.html
things that keep that from happening,
spark retarded.
tps idle switch stuck open for all the ways, even too tight throttle cable and more.
isc JAMMMED
ISC UNPLUGGED ecu.
(massive air leaks some where, only causing LEAN, if you have metered air leaks huge the idle RPMs SCREAM.)
as I said 500 is Dead wrong. it bet the first thing id notice driving. what's with this John Deer 1900 tractor speeds??(my friend collects them ,funny things to watch, wild !)
and its 2nd job, is recalibrate if you have minor air leaks. in the induction, (SAY tv BORE WEAR afte 300k miles)
and 3rd is a older tired, engine (weaker) re calibration. (olders engine have weaker vacuum)
the ISC can in fact compensate for leaks, or any weak engine , hands off. that is its job. so long as , ISC not jammed, or huge leaks.(or huge lean)
but you need to keep the duty at 50% hot. (when at 50% 800rpm locks in, in ECU SERVO mode, and is hard coded that spec.)
so, if you unscrew the bleed and like magic the RPM leaps to 800 , that means the ISC just woke up. (works both ways, too fast RPM screw it in)
keep in mind 2 facts.
the ISC can not correct huge leaks. (it can not close more that 100% ) so CANT work with huge leaks, (case in point ruptured brake booster diaphragm)
and the opposite of that is true. if say the bleed is closed 100% the ISC (ecu is brain of that) MAY NOT BE ABLE TO OPEN ENOUGH TO GET 800 RPM.
[i]lazy fingers caps look sorry.[/i
your case is rare here, low RPM. (discounting the huge EGR stuck open issues) most are too high RPM issues.
one easy way to fix this, (assumes nothing major bad)
is to see the DC voltage on the ISC pins to 7vdc running, by turning the bleed screw .
my guess is it will read 12 to 14v now, (wrong)
and you open the bleed screw and as you do the voltage drops. and ISC wakes up.
but keep turning until 7vdc is hit, (some older meters cant do this, too slow , old meters or dirt cheap ones)
suzuki uses a tool you can;t buy. it uses a current mode duty meter, its not made.
but there 3 tools that do work
most nice DMM on DCV volts 20vdc scale.
nicer meters with DUTY mode (on dial)
and all scopes ever made can do 200 HZ isc signal. all can
2 other things cause rpm low and isc dead.
are
lean AFR (will bogs like crazy)
or spark timing set way retarded....
nut shell:
connect meter.
turn screw for 7v "bleed"
800 happens under software (firm) in ECU, the brain is programmed to 800 hot, (1000 under p/s overload or A/C on) hot.
its unstoppable this once it works,
der bleedn splunken
http://www.fixkick.com/fresh-air/Slide_S...ge_32.html
things that keep that from happening,
spark retarded.
tps idle switch stuck open for all the ways, even too tight throttle cable and more.
isc JAMMMED
ISC UNPLUGGED ecu.
(massive air leaks some where, only causing LEAN, if you have metered air leaks huge the idle RPMs SCREAM.)
as I said 500 is Dead wrong. it bet the first thing id notice driving. what's with this John Deer 1900 tractor speeds??(my friend collects them ,funny things to watch, wild !)
http://www.fixkick.com