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Idle high after cleaning throttle body and lashing valves...
#3
i need exact RPM ho> ?> 200 higher tells me nothing.

the ecu controls idle. Hot. i need the HOT RPM actual. 750 to 850 rpm is the hot rpm spec, on car, 800 is perfect. (a/c off, P/S not in overload)
this is servo function, in the ECU, it opens the ISC to make it run faster, and closes it for slow, and gets it to 800 in this fashion. (in a servo loop control action)
that screw is the IDLE speed, duty cycle adjustment.
It only works to change idle speed, if the idle controls are dead.
It is adjusted in the factor for 50% duty cycle.

ok the egr opens now and near stalls GOOD. . but does it open , by it self if you gun the engine in neutral. parked.? this should work.


the duty cycle calibration is not easy with out a scope. the DLC connector has a Duty pin, but needs a special undoc. Suzuki tool to use.
there are other ways,
what is Hot rpm , with the ISC unplugged. ? use the top TB idle bleed to set idle near 600 rpm, if this is impossible , then you have air leaks.
?
but lets forget that for now.
engine hot, you have xxxx rpm, (what is xxxx) now you turn on all loads, A/C , heater fan, Defrost rear(if have it) head lights. what is RPM now.
this puts a large load on the engine via the Alternator. the RPM must hold or drop 100rpm and the go back to 800 fast. in 1sec or so... if yes the idle controls are working.

my guess is this test will fail. hot. remember hot is 180F+ coolant and never 150F. or all setting by you are futile.
http://www.fixkick.com/IDLE-AIR/idle-index-home.html

i make sure the engine holds closed loop hot. at ilde. first. if not i fix that first.
if rpm is way too high or low. i test to see if the iSC has lost control of idle. if yes, i find the cause next)
causes are many, over 50 causes, seem yours is more like 2 or 3 causes. now. if at all.
not in suzuki limp failsafe mode. The IAC is not leaking air or any air leaks in the induction, paths, from MAF to intake valves.

in the factory or shop. (long ago) the tech, would get the engine running perfect first, in closed loop.
then, attach his , Duty meter to pin 6 and ground

[Image: CAL-car-diag2.gif]

then turn the idle air bleed screw, to 50% duty. (this is the point the ISC is half open, and closed. its in the middle of its command authority, ASE speak)
but you dont have this meter, and ive tried many a meter get this working, and all failed, i think the suzuki meter uses some current mode to do this magic. (undocumented by suz)
so i use a scope, and set the duty on the ISC directly to 50% that is 2.5mS 0.0025 seconds, high then low. on the scope
seen here.
[Image: iac-wave1w.jpg]
this is not the correct testing mode below (out of context) but shows the signal
on a hot engine turn the bleed screw until the waveform is equal on both sides. the period is 5 Ms. 0.005 seconds.
but you say, gee i cant do that ., sure, so what can you do , ?
answer:
we can ball park it.

set hot RPM with the ISC connector unplugged. this causes the ISC to close 100% and idle to drop way below 800.
then plug it back in and idle will go to 800, the ecu reads engine RPM and adjusts the ISC to attain, 800 RPM.
if not, this speed control function is out of order.

i need all the facts above to find causes.
hot idle RPM? absolute not 200 higher.?
and if the load test works, say RPM is 800 hot, and i put on all electrical loads, does it hold at 800?
hot RPM ISC unplugged, electrically .?


idle speed controls are the last thing to work right, all else must be correct. then the controls can take charge.

how is that?
http://www.fixkick.com
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RE: Idle high after cleaning throttle body and lashing valves... - by fixkick - 08-16-2014, 09:18 PM

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