It's a short video; I had to put it on repeating loop to try and figure out your morse code message. LOL
This may be my problem. I checked my IAC and I get 12.3 ohms (good). No continuity between either terminal and the housing (good), but when I connect 12 volts to the IAC contacts I get no click (bad). The wiring harness going to the IAC seems to carry 7 volts. When I pull the IAC air hose off the air horn I feel a strong vacuum (good) and when I put my thumb over the hose, the engine slows (good) but when I disconnect the IAC wires, nothing changes (bad). My mileage recently dropped from 25 (mostly city) to 18 (bad). The Tracker is a 1994 8valve, two door auto. It starts instantly when COLD. It idles very fast for a few seconds and then slows slightly. After the stat housing gets hot, the idle drops lower and the engine sounds good. If I shut off the engine for more than a few seconds I can only restart if I hold the gas pedal to the floor and it still takes 5 seconds of cranking. Everything is new (plugs, wires, cap , rotor, fuel filter, air filter.) The EGR valve is clean and working. The fuel pressure regulator is good and the only code I get from the OBD-1 is a constant "12." I'm pretty sure the problem is the IAC. What steps are involved in removal (e.g. do I need to drain the coolant) and how do I fix the problem (short of buying a new very expensive IAC)? Do I really have a problem or does everything I've described sound normal for an old 1994 Tracker?
that was great! my page really helped someone.
mine was stuck open for 1 year, LOL. too cheap to buy a new one.
yes , yours is stuck, if it dont clack , it is stuck with 12vdc applied.
be sure to try both polarities with the connection to coil . and 12vdc source.
ok here is the skinny.
soak the heck out of it with carb cleaner.
that plunger can be spun ! and stroked, you cant hurt it.
fill it with your Cleaner,and start with a tiny screw driver , and spin that plunger tip.
once it spins and is free (good sign), then you can stroke it.
no puns here,ok,, now wiggle it back and forth and flush,
the key is the crap hidden back towards the coil side.
the piston is a fiberglass type and will not rust. the bore is brass.
good design it is, but PCV and EGR crap back up into here. ( no joy)
once it is free , then try your test.
it must just bearly close the valve with no power, (use lips to blow in air nipple)
then apply power ,like my video and it must move back 1/8 to 3/16 of an inch CLICK.
then unpowered drop back to the rubber lined seat. (a ring of rubber there)
it can be calibrated. but if yours closes 98% it is ok.
the hex screw balances the two springs inside.
if it clicks and seats, then it can be made to work perfect.
yours was stuck closed , killing 1/2 the start air , makingcar want to flood. (feather foot)
were is sticks makes for hard starts, sometimes.
mine started perfectly ,but it stuck in the middle. ( luck i guess)
there is a company that rebuilds them, Beck? or some other, will look it up.
Im happy someone else is trying to fix one of these bad ones.
we can develop a better cleaning process? maybe.
cheers.
that was great! my page really helped someone.
mine was stuck open for 1 year, LOL. too cheap to buy a new one.
yes , yours is stuck, if it dont clack , it is stuck with 12vdc applied.
be sure to try both polarities with the connection to coil . and 12vdc source.
ok here is the skinny.
soak the heck out of it with carb cleaner.
that plunger can be spun ! and stroked, you cant hurt it.
fill it with your Cleaner,and start with a tiny screw driver , and spin that plunger tip.
once it spins and is free (good sign), then you can stroke it.
no puns here,ok,, now wiggle it back and forth and flush,
the key is the crap hidden back towards the coil side.
the piston is a fiberglass type and will not rust. the bore is brass.
good design it is, but PCV and EGR crap back up into here. ( no joy)
once it is free , then try your test.
it must just bearly close the valve with no power, (use lips to blow in air nipple)
then apply power ,like my video and it must move back 1/8 to 3/16 of an inch CLICK.
then unpowered drop back to the rubber lined seat. (a ring of rubber there)
it can be calibrated. but if yours closes 98% it is ok.
the hex screw balances the two springs inside.
if it clicks and seats, then it can be made to work perfect.
yours was stuck closed , killing 1/2 the start air , makingcar want to flood. (feather foot)
were is sticks makes for hard starts, sometimes.
mine started perfectly ,but it stuck in the middle. ( luck i guess)
there is a company that rebuilds them, Beck? or some other, will look it up.
Im happy someone else is trying to fix one of these bad ones.
we can develop a better cleaning process? maybe.
cheers.
OK, I'm making progress. My piston was gummed up and frozen but with a lot of poking and spraying with carb cleaner, it broke free. I finally get clicks when I apply 12 volts. I adjusted it so it closes completely when power is removed. I did this by blowing into a 3/8" tube connected to the air inlet and using probes attached to a 12 volt transformer (only .5 amps but it worked fine). Things got a little better when I remounted the IAC. The idle now slows slightly when I pull the electric connector. This is a definite improvement but not enough. Even at full operating temperature the idle is still very fast. When I pull the IAC air hose off the air horn there is a very strong vacuum. This vacuum drops about 40 percent if I unplug the power from the IAC but the IAC valve doesn't close completely and the idle, although is slows slightly, is still very fast. If I put my thumb over the IAC air intake tube, normal slow idle is restored. It appears that the IAC can't be perfectly adjusted on the bench. It seems I need to tighten the adjustment screw to the point where the valve closes completely when the power is unplugged with the engine running. Is this correct? If so should I make this adjustment right after starting a cold engine or should such an adjustment be made after the engine is up to full operating temperature? To recap: I get a perfect slow idle if the engine is at full operating temperature and I put my thumb over the IAC air inlet. I would like the IAC to do this automatically as I believe it was designed to do. (I understand that depending on temperature and operating conditions the valve will still "pulse" from time to time when adjusted correctly.) Am I wrong in assuming that all (or 90 percent) of the incoming IAC air should stop when the IAC power is unplugged? Right now when I unplug the IAC there is only an approximate 40 percent reduction in air flow. Also I still have to hold the gas pedal all the way to the floor when doing a hot engine restart. The car still starts instantly (without touching the gas pedal) when completely cold.
As far as the coil is concerned, I noticed that when the IAC is cold, I get 12 ohms resistance but when hot I get 14 ohms resistance. I trust this is normal resistance?
yes, normal resistance.
btw , none of this is in any manuals.
on our cars, 8v
we have 5 air sources.
my calibration of the iAC-E is pure theory.
my logic, the ecu cant push the plunger, so it must be seated at rest.?
you car is a "hot start air starvation issue" ok.
Part 1.
Now, when you start cold ,the bottom TB, IAC-T gives extra air and none hot.
so i do not suspect that.
next part 2
the butter-fly must not be gummed up(or blocked) and that throttle stop screw must be
painted and set to . 0.25 inches.
part 3 .
the dash pot.
this device holds the throttle open for cold starts and hot starts.
even more then #2 above. the only difference is the length of time it stays open.
hot or cold (ecu decides that based on ETC coolant temp)
Part 4 is IAC electric, the ECU controls this full time, under all conditions.
it even helps save fuel during deceleration ! buy bleeding air, at fuel cut time.!
Number 5:
and last is the TB bleed screw. try closing that way down and get idle under control.
All the above ASSUMES ,no illegal induction leaks.
as 8v will only idle fast if there are leaks and make full power.
that dash pot , has a spring inside, that holds open the throttle ,key off
the vacuum to the dashpot does not HAPPEN until after the car starts and after up to
10 seconds cold (longer if super cold) then the VSV opens, the DASH pot retracts !
both on cold and hot starts. 1200 rpm to lower ,and a slow drop to 800 as IAC-T does its magic.
make sure this DP is open on all starts.
cheers.
PS: thanks for feedback , Im still working on mine. too.
my iac is sitting here, says, put me in and do like long rod.
My idle screw is already all the way in and the idle is still pretty fast. All the hoses look good and are connected. I've sprayed everything attached to the throttle body with gumout and starter fluid while the engine is running and get no changes. If there is illegal air getting in I can't hear it, see it or find it. I still think the IAC probably needs fine tuning/adjusting while mounted to a running engine. I'm uncertain as to if the motor should be hot or cold during such fine adjustment.
I checked my dash pot. When the engine is off, the plunger contacts a screw on the throttle lever. After I start the car and run around to check again. The plunger has by then backed away from the throttle lever leaving a 4mm gap. I still need to hold the gas pedal to the floor when starting hot. I never smell any raw fuel. So what's my next step?
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basics IAC testing.
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