89 tracker stalls when slowing down.. HELP

[Jasenford]

i got my 89 tracker 1.6 8V back from the shop today and drove it off.. when i come to a stop sign it always stalls..Would the IAC be the issue becuase the MECH. told me it was either bad or needed to be cleaned.

[Rhinoman]

Could be, could also be a badly adjusted or faulty TPS.

[jtgh]

not easy , the idle thing.
key points
1:is ECU trying to adjust idle , or not.?

not: then its bad or is in LIMPHOME mode. bad sensors.
Is ECU trying? (even trying to adjust idle)
yes,1: its dirty.
yes,2: you have an air leak , and it can not close down enough to hit 800 rpm.
yes,3: engine is very sick. (bounching vacuum, low compression ,imbalanced compression.
yes,4: a whole laundry list of things, from clogged CAT con's to cracked manifolds.

in the big book it says idle is the last thing to work or to adjust. all else must be correct.

even:
slipped timing belt
maladjusted ignition timing.

it could be easy, or hard to find.
tis the truth.

cheers


89 is 8v.
what is rpm hot.
when you pinch the ISC air tube ,what does engine do. (edit my dumb question; 89 has no tube, huh?) tis true.
speedup, slow down, stay same.?

[Jasenford]

the idle does bounce so i guess in a way that is a good thing

i tried the pinching the hoses method for he vacuum but no results, idle stayed the same

the engine is supposed to have around 60 - 70K miles on it, or so thats what the mech said when i bought the motor, the compression is good, and im trying to find my timing light to check timing.. The mech said he adjusted the timing but i just want to make sure

The timing belt and sprockets are where its supposed to be

When engine is hot it runs between 1500 - 2000 RPM's

And im not to sure what the ISC is, once i find that out i will do that test

Also is there a way to check the CAT and see if its clogged, and also check the manifold for cracks, or would i be hearing the exhaust leak?

Thanks

[jtgh]

corrections: edit !
89-differences


That idle is way off
this 8v has the ISC idle speed controller on the side of the TB, throttle body.
it has a top air hose (other 2 are water heat) pinch top hose ( edit , no top hose sorry, but what to do ?)
correction:read this.
89-differences
just clean it is all you can do on 89 or unplug electrical cord but that is hooked in with injectors.
on this ISC. if the RPM does not drop below 800 .
1: you have an air leak.

what is the issue.
is the Dashpot retracting after starting , 30 seconds max.
http://carfix.stufftoread.com/fresh-...-body+dp1w.jpg
the dashpot must retract and stay so full time running HOT. MUST !

and do check first Rhinomans TPS calib. procedure.
TPS testing

see my new feeler guage matrix, try the 1.6L TBI column.
see 8v proc.

cheers.

[jtgh]

keep in mind the AC must not be on, or the switch for it stuck on.
with this switch on, the ECU sees that, and raises rpm by 200.

[Jasenford]

ok i think i see it,, does it say mikuni on it?? if so what would you prefer to use to pinch the hose since it is kinda stiff

[Jasenford]

o nevermind it is the part below the one that says mikuni.. sorry

[Jasenford]

i pinched the hose that i think your were talking about, and the idle stayed the same, im trying to figure out how to adjust the TPS but i just cant seem to figure it out, for some reason i just cant comprehend

[jtgh]

no. (?)
89-differences
corrections, see diff page.

see my parts finder page.
its there.right.
how-to-find-EFI-parts

see this photo
your ISC is rotated 90 deg. and is no different. (ignore looks of it)
i use the old name in my suz book , iac. (other books call it isc.
idle speed controller or idle air controller, same0same0.
the other iAC is the coldstart air controller thermal.
the Dash pot is the coldstart fast idle valve.

on all 8v there are 3 air control devices and work diff. complex it is.
ISC is the highest one of the group

bottom ,of TB is cold start Idle air. 100% thermal and closes hot.
Dashpot is , open at start and closes in 5 to 30 seconds. ECU controlled.
Dashpot is closed 100% time hot and running, if not it is bad. ask how to fix.
last is the ISC (on top highest point of T
it is used for a host of things.
Idle speed at all times.
fuel cut.
Egr tests. and many other things. but idle is #1

if the TPS switch closes ,at idle the ecu says , enable idle speed control software.
it then starts pulsing the ISC.
this pulsing holds the idle at 800 rpm under all conditions,
but AC on and PS overload.
under AC on , ,it raises idle to 1000 rpm.

that's the kit and cahboodle.


there is a Idle bleed screw for setting idle.

If you pinch the top tube of the ISC,
mine drops to below 800 , as it should.

next , FSM words.
apply 12vdc to the ISC , unpluged, at the IAC itself.
and then disconnect the 12v.
you just switched from wide open to wide closed.
the idle should go to above 800 , then below 800.
if not, there is a serious problem with idle.
you see why?, if you can make it work correctly , how can the ECu?


once you get to this point, you must then find out why?
air leaks ,bad ISC.
bad motor. ( can be manifolds ,etc vacuum varying, compression issues ,suck valves)

or ecu in limphome.
or TPS not signalling IDLE at ALL.


TB = Throttle body