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Idle high after cleaning throttle body and lashing valves...

My idle went up about 200-300 rpm after adjusting the valves and cleaning the throttle body and new timing belt. I found two valves that were really tight. The ones nearest the firewall.

How do I bring the idle back down? I looked for 20 mins in the fsm and couldn't find a procedure. Is the screw on the upper back throttle body the right screw to bring it back down? It also seems like that when I rev the engine, it takes a bit for the rpm to settle down. Is this normal?

I have to say that my engine sings a new tune after all this work! It sounds like it's a fully tuned motor! I'm blown away. It really has a vibrant sound and seems more peppy! I can hear it in the exhaust note!


ps. EGR test now brings the engine idle down! Very happy!

All the work was definitely worth it!
95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
I found the procedures in the fsm for "IAC Duty Adjustment." 6E3-C2-9. Will try this tomorrow.
95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
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.

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 , ?
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?

I took it for a drive last night. My idle would not come back to the same place each time. I was seeing 1100 rpm, then it crept up to 1200 rpm. Prior to removing the TB, it held steady near 800. If I blip the throttle it seemed to settle at a different rpm.

Do air leaks cause the rpm to go up or down? That's my first guess since I had all the hoses out. Is it possible I did something to the IAC control on the TB? I was spraying a lot of cleaner in there to get all the carbon out.

I'll do some of the tests you suggest above. It sounds like I don't want to change that fuel air setting until I check the hoses?

I saw a youtube video where the guy was spraying the hose joints with some carb cleaner to find leaks. If the engine changed rpm, he knew he found the leak. That's seems most likely my problem given the fact that I had all the hoses off. Engine runs superb otherwise.

thank you!!
95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
1100 is failure.
yes, air leaks are bad on all MAF based engine, even on new cars. this is unmetered air.
i hope you didnt change the throttle stop screw. while cleaning, it, or set the throttle cable tight its set loose, always loose. pre FSM. (see 95 fsm it same way )
the 96 book cover the 16v well. only the 0BD2 parts are new.
if the engine is not 180f, all this testing and checks are usless, this is 1st on all engine, the ECU changes MODE by TEMP. 180F or more. is it?
then closed loop, you dont have a scan too so cant see closed loop fail. and if it does, this IS NEXT,
if the engine is not in closed, loop changes are the fuel mix is way too RICH.
when rich air leaks cause racing,, not slow idle. see? (equation too much fuel, and too much air, = racing)
this is why im all over closed loop status, hot idle. like tick on a hound dogs butt.

yes, air leaks are all bad.
but why not disconnect the ISC to see what the natural air leaks are, with the ISC disconnected it closes, 100% (you can test that removed, pre my video and page on same)
but its closed 100% on all working ISC or 99% on old ones is ok.
so if there are leaks. the idle is now over 600 rpm, finding air leaks is lots of work on any 16, see all those hoses, and that large pipe MAF.
mine large pipe the rear mount lug broke off, and was sucking air there. they can come from many places.
all induction air paths. injector cushions(base gaskets) intake gaskets, main air pip rubber ring messed up. IAC UNDER TB LEAKING., SOME ONE TOUCH THE IDLE STOP SCREW, that is a no no.
someone opened 100% the bleed screw (top side of TB under plastic plug) or lost it.

finding leaks, is hard, sure using spray , water, or propane finds leaks. sure , and so does the shop smoke machine. lots of ways, inspections, doing leak down tests on all lines.
the IAC is very hard to damage, near impossible, its a wax powered air valve. very very tough.

all air leaks are bad except
IAC (its closed hot at 150F and above) so it not it.
Bleed. screw.

if you block those 3 paths the engine stalls NOw, if not it got a horrid air leak. why, bacause there is NO AIR NOW,you blocked it.
see my path drawing

dedicated page just to 16v old

photo of paths. a, b,c,d , path d is ILLEGAL path, at all times, (throttle cable set tight? wrong)
path b is closed hot,if not, the IAC is bad.
path c is the bleed, or duty cycle setting screw.
path a and 13 is the only major path of air. this is the ISC, if you unplugged it hot,the idle will drop very low. if not you have leaks.

[Image: induction1a.jpg]

one guy found the coolant path to the IAC blocked
and the IAC just stuck open, naturally.
i use a pyro gun to find those. the IAC must be hot, near 170f on the casing is normal.. if way low the path is blocked for water.
the IAC is a cold start warm up air supply, only. at all other times is closed, hot.

keep in mind, no scan tools means
you are blind, you can see closed loop work, or not work.
if not in closed loop we fix that first, idle is dead last on the list.
but if there are air leaks, the ECU drops closed loop, this is called this LOST, (confused) and many times, no CEL glows. (un like new cars)

do not spray wd-40 , to test or air leaks, in 2001 one WD took out the propane gas and now uses, CO2 or freon. neither will burn.
use carb cleaner or propane, latter is vastly safer. and some use water. (water blocks the leaks , well only the tiny leaks so water testing is near useless. IMO.
all the above is risky but water.
the shop uses a smoke machine (tricky to use, ask) but is risk free.

on the suzuki all the VSV valves are open key in pocket, confusing many a mechanic. a gift from SUzuki that.

the drawing does not show the hoses. most.
that is because they dont leak and are not part of the normal path of air.
also a weak maf can cause the ECU to get lost. clean it very very very carefully its $1000 new.

you didnt mess with screw seen here in 16v TB photo?


if messed, set it using smallest feeler gauge on earth .0005" is mine
or as one forum guy said,
set it 100% closed
then turn the screw to the point that the TV moves .0005" the smalled humanly seen movement. lock it down.
this valve is closed. 99.99%
the screw and minisule gap is not for air, it's to prevent throttle jamming...!!!!! only !!!!
sorry if you did that, im just guessing. but you did clean the TB so.......

one guy turned the bleed, screw 1/2 a turn CW and the ECU took back control and went to 800 rpm hot.
but the duty cycle is way off. he has air leaks and hid like 1 in 3 or ?
the ECU needs at least 200 RPM head room, that is 600 rpm , ISC unplugged.
ball park, data. no suzuki doc tells this secret, you learn it doing tests on good engine, no leak inductions.
also on egr, see my page here in EGR, and the 1994 rule.
USA rule, USA ECU, i do not have the cut in date on the rule, what body VIN serial number cut in date or serial, only 1994 it began.
i forgot this rule and my page shows my research on that.

I'm looking for the 1994 rule. Not sure what this means. Can you provide more detail? I'm slow! Smile

95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
the book FSM book 1994, is hard to find, and see. i dont have a 1994,
and they changed the EGR rules that year. its a major change.
EGR only opens moving or not.
early 94 is not, late is moving.
all obd2 cars are moving .
but this moving malarkey started in 1994.

Suzuki love to change rules ,mid build years,
On July1. 1993 the started making 1994s, that is correct, they must make them EARLY to comply with USA EPA mandates. (and DOT, and others) so 94 cars are made starting in 93.
but , they make some changes, later, like Dec 15th(wild guess) and change more things in the 11th hour. to make EPA HAPPY.
all cars do this. and is a pain to the maker, and to the car tester fixer.

keep in mind the MOVING rule is 100% software, ECU internal hard coded, firmware.
my wild guess is your car is a moving EGR test car. if still a 58B00 ecu.... USA -MT codes.
that is why i do the tests. to see if car is moving car or not. for EGR, saves me guessing and removing ECU and scratching my head.

my test.
if engine is hot, and you gun the throttle , the EGR main diaphragm flexs,, not moving car.
that assumes it all works, if it dead. then i must put my meter (volts) to the EGR VSV
and if it switches to 0v across this coil , racing the engine hot, its a not moving car, ECU.
there is no other way, unless you can read those secret , ECU Mitsubishi codes, (i only know one man on earth that can , in part) he is in UK.

EGR is fun, right? sorry,its so convoluted. but this is normal on 94, 95s are all moving EGR cars. rear axle must spin to test it.
That makes sense. Before I cleaned the air hole behind the throttle body, the CEL came on while I was on the highway.
95 Geo Tracker, Build Date 1/95,16v, Fed, Cami, 4x4, MT, Headed for Grenada.
the moving test takes 2 or 3 (2 man , the second man turns the rear tire by hand, yes, this can be seen for free in the 1996 FSM)

see that here.
is not the JOKE , truth is more odd than fiction, ??? in this case, truth is very very odd.
read this.
chapter C6
page 1 , one see the word STOPPED. in bullet #3

then we must change chapters to find the P400 failure (51s on 94' late and up)
pdf page 39
doing the live test. starts. here.
see chart , this is GMs lame attempt at translating real SUZUKI FSM.
see page 40 step 2.3, and the causal, its in NEUTRAL, and tire spins?. that is YOU turning that tire. what a joke that page is.... but is accurate.

my car failed step 9, (and lots of others but....)

the suzuki books is way better on this topic the GM logic charts are full of errors

the EGR vsv has 12v on one side all the time key on, this is power, side, if lost 12v here, EGR is on all the time, off idle. (blown fuse)
the ECU grounds (a simple transistor) the VSV other coil side, at key on, this closed the VSV, until the ECU decides to open it,

do not read the 96 book on EGR, only those 2 lines., stopped, and tire turning apply to your older car. (all in the software)

keep in mind you can test the whole EGR system, (not ECU parts)
with the EGR VSV connector removed.
this cause it to be more like say a 1993 car.
in that the car does not need to move. to get EGR action,only the throttle.
Ill add that to my 94+ page.. thanks, for making me think of that.

yes, i think the ECU does the 51 test only on the highway, under load. 94+
the moving rule is just for that. under load the EGR is most accurate, with CAT back pressure , controlling the Flow. in the EGR, via the Bark tube.

under load the NOX polluton is very bad. (combustion temps are max under full load).
the EGR does not reduce NOX to zero or even close.
the CAT eats up the remaining NOX, they work as a team.

my wild guess at the moving rule.
is that the EGR, may cause misfiring, when racing the engine in neutral, so they decided to end that in 1994.
that is my best guess.

It seems moving even 0.1 mph is moving, so turning the tire by hand works.
if the VSS clicks at any speed, your are moving and ECU is happy.

on newer cars its more complex, some tests are SUSPENDED if other tests are bad.
on my 1996, the front OXY sensor was dead.
so the ECU suspended all CAT tests.
smarter than the average bear.....

keep in mind the EGR test might end, if ECU is in limhome mode.
this fools many a mech, they get engine running really well and bam DTCs , they wakeup, funny how that happens.

like a man coming out of a coma, he goes, gee my tooth hurts. (abscessed and swollen)
same deal.
for same reasons.

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