gen4 5s-fe IAC valve terminals resistance

[fenixus]

hey, I have a problem. as far as I know my multimeter is correct (tested on spare resistors and it's good), but for some reason whenever I test resistance on 2 IAC valves I get idiotic results ...

terminals are (from top to bottom):
ISCC
+B
ISCO

a) old IAC valve mounted on car
+B & ISCC = 64K ohms (that's 64 thousands ohms)
+B & ISCO = no continuity up to 2,000,000 ohms

b) new OEM IAC valve off the car (p/n 22270-74400)
+B & ISCC = 27K ohms (that's 27 thousands ohms)
+B & ISCO = no continuity up to 2,000,000 ohms

Per gen4 FSM those resistance should be
17 - 24.5 ohms when cold (-10C/14F up to 50C/122F)
21.5 - 28.5 ohms when hot (50C/122F up to 100C/212F)

what am I doing wrong? am I having a new bad valve here in my hands?

[hill8570]

+B to ISCC looks sort-a kind-a OK (a little high, but better than 64K)

Yeah, +B to ISCO looks pretty bogus.

Just for giggles, have you tried an op test (9V battery, + to +B, - to either ISCC or ISCO)? +B to ISCC should close the valve, +B to ISCO should open it.

[JohnGD]

Try swapping leads (try both red on B+ and then black on B+). Use the lowest ohm scale and see if you have changes in the readings. Otherwise I'd suspect an out-of-spec valve.

So before you install try jumpering battery voltage to the connectors and see if they click on both open and close pins.

[fenixus]

hehe, that's what I initially thought, kinda good (not quite), but better than old one LOL

the other pair is puzzling me totally ... and why am I getting reading in thousands of ohms and not plain ohms??? that I cannot understand ...

just returned from car with my electrical crap backpack, full of wires, clips and 9V battery

will post more soon.

Originally Posted by hill8570

+B to ISCC looks sort-a kind-a OK (a little high, but better than 64K)

Yeah, +B to ISCO looks pretty bogus.

Just for giggles, have you tried an op test (9V battery, + to +B, - to either ISCC or ISCO)? +B to ISCC should close the valve, +B to ISCO should open it.

I tried reversing leads and got same results ... very strange ...

I am using alligator clips now and cycling the range dial, numbers jump sometimes between 200 ohm range and 2000 ohm range on dial, but once they stabilize it's always same and weird ...

will attempt energizing it with 9V battery in a few moments. be right back.

Originally Posted by JohnGD

Try swapping leads (try both red on B+ and then black on B+). Use the lowest ohm scale and see if you have changes in the readings. Otherwise I'd suspect an out-of-spec valve.

So before you install try jumpering battery voltage to the connectors and see if they click on both open and close pins.

[fenixus]

god damn it! it's bad!!!

when I jumper the upper pair (+B and ISCC) it tries closing briefly (it doesn't click, but I feel it vibrates trying doing something), but then immediately returns to half open position if I keep it energized and stays there.

when I jumper the lower pair (+B and ISCO) it doesn't do anything at all ...

... shit ... crap ... junk.

part is original Toyota (JAPAN) with part number imprinted on one side. Other side carries the name Aisan (if reading correctly that type face).

[ajkalian]

Originally Posted by fenixus

god damn it! it's bad!!!

when I jumper the upper pair (+B and ISCC) it tries closing briefly (it doesn't click, but I feel it vibrates trying doing something), but then immediately returns to half open position if I keep it energized and stays there.

when I jumper the lower pair (+B and ISCO) it doesn't do anything at all ...

... shit ... crap ... junk.

I believe the correct phrase is shit....piss...fuck.

At least that's how I learned it.

Anyway, I dug out a spare IAC and the part number is 22270-20040 so it might be different from yours. With the tubing facing the right, red lead on the left terminal, black lead on the center I get 21.6 ohlms. Red lead on the left terminal, black lead on the right terminal I get 42.5 ohms. Red lead on center terminal, black lead on right terminal I get 21.8 ohms. Meter is set on 200 scale. The readings are the same if I reverse the black and red leads from the Multi-meter. It's an el-cheapo deluxe Harbor Freight Cen-Tech.

Hope this helps.


.

[JohnGD]

That's today's Toyota "quality" I guess.

[fenixus]

haha LOL yeah I heard that phrase before

your IAC's resistances are good.
to compare numbers easier, your left terminal is my top one, your right terminal is my bottom one ... go figure in what shape this valve is ... super mega strong resistance on closing and no continuity at all on opening ... end result is it stays half open all the time ... nice job Toyota!

my multimeter is also an el cheapo Centech from HFT

Originally Posted by ajkalian

I believe the correct phrase is shit....piss...fuck.

At least that's how I learned it.

Anyway, I dug out a spare IAC and the part number is 22270-20040 so it might be different from yours. With the tubing facing the right, red lead on the left terminal, black lead on the center I get 21.6 ohlms. Red lead on the left terminal, black lead on the right terminal I get 42.5 ohms. Red lead on center terminal, black lead on right terminal I get 21.8 ohms. Meter is set on 200 scale. The readings are the same if I reverse the black and red leads from the Multi-meter. It's an el-cheapo deluxe Harbor Freight Cen-Tech.

Hope this helps.

.

sad, isn't it? the newer the parts the shittier they get. this new parts is in pretty much same bad (a little better) shape as the 11 years old valve mounted on car which failed within last 2 years, with 81k miles on it now ... a joke.

need a replacement fast ... wanted to swap it this weekend ... PM'ed Gary already, let's hope he sends me a new one tomorrow...

Originally Posted by JohnGD

That's today's Toyota "quality" I guess.

[ajkalian]

While you have a new IAC sitting on the counter, could you take a pic of the one end that has the two screws that secure a plate to the end of the IAC. The plate has 1/8" elongated holes for some sort of adjustment.

When I took mine apart, of course I marked it with a marks-a-lot so I could put it back together in exactly the same orientation. Only problem was that I cleaned the IAC with laquer thinner and, of course, it washed off the marks. So I have no idea what the correct position is. There is some yellow paint on one of the screws, but it's not helping me at all.

I tried rotating the plate but it didn't seem to affect the opening of the valve one way or the other when I applied battery voltage. I'm guessing that it has something to do with temperature since when I boiled it the spring moved, so there must be some sort of adjustment, but I have no idea what it might be. The FSM says just to replace the IAC, rather that service it.

.

[Oldcar95]

What made you look at it? How was the car running?

[JohnGD]

The cover plate is for turning the bimetal thermostat spring inside. The spring turns a plastic cup that forces the vane rotor to an open position when it's cold but leaves it to ecu when it's in the moderate temp range.

Just remove the plastic cup and let the ecu do the rest. Give it a try. Besides, the spring can be turned and messes things up too. I'd just bypass the silly thing by taking out the small cup.

A bimetal thermostat spring and a magnetic motor on an ecu-controlled car with all sorts of sensors. It's got to be one of the stupidest designs I've seen.

Originally Posted by ajkalian

While you have a new IAC sitting on the counter, could you take a pic of the one end that has the two screws that secure a plate to the end of the IAC. The plate has 1/8" elongated holes for some sort of adjustment.

When I took mine apart, of course I marked it with a marks-a-lot so I could put it back together in exactly the same orientation. Only problem was that I cleaned the IAC with laquer thinner and, of course, it washed off the marks. So I have no idea what the correct position is. There is some yellow paint on one of the screws, but it's not helping me at all.

I tried rotating the plate but it didn't seem to affect the opening of the valve one way or the other when I applied battery voltage. I'm guessing that it has something to do with temperature since when I boiled it the spring moved, so there must be some sort of adjustment, but I have no idea what it might be. The FSM says just to replace the IAC, rather that service it.

.

[fenixus]

here you go man!

Let me know if you need more pics and which side, angle, close up or so.





It doesn't look like there is much space for error/shift on re-assembly on my unit though. hope it helps.

Originally Posted by ajkalian

While you have a new IAC sitting on the counter, could you take a pic of the one end that has the two screws that secure a plate to the end of the IAC. The plate has 1/8" elongated holes for some sort of adjustment.

When I took mine apart, of course I marked it with a marks-a-lot so I could put it back together in exactly the same orientation. Only problem was that I cleaned the IAC with laquer thinner and, of course, it washed off the marks. So I have no idea what the correct position is. There is some yellow paint on one of the screws, but it's not helping me at all.

I tried rotating the plate but it didn't seem to affect the opening of the valve one way or the other when I applied battery voltage. I'm guessing that it has something to do with temperature since when I boiled it the spring moved, so there must be some sort of adjustment, but I have no idea what it might be. The FSM says just to replace the IAC, rather that service it.

.

varying and usually too low idle, especially when driving with a/c turned on.
other clue on problem was having usually too high (positive) fuel trims, but not always, again more with a/c running.
third thing was havin less power when taking off from a dead stop (lean condition) which was coming back to normal once engine speed reached 1.5-2k rpm.

seem slike a faulty (half open) IAC is allowing the extra air when not needed and leans out mixture (computer tried compensating) or when a/c runs the extra air amount is not enough resulting in choking (too low rpm), unless I understand it all wrong.

Originally Posted by Oldcar95

What made you look at it? How was the car running?

[ajkalian]

Originally Posted by JohnGD

The cover plate is for turning the bimetal thermostat spring inside. The spring turns a plastic cup that forces the vane rotor to an open position when it's cold but leaves it to ecu when it's in the moderate temp range.

Just remove the plastic cup and let the ecu do the rest. Give it a try. Besides, the spring can be turned and messes things up too. I'd just bypass the silly thing by taking out the small cup.

A bimetal thermostat spring and a magnetic motor on an ecu-controlled car with all sorts of sensors. It's got to be one of the stupidest designs I've seen.

No kidding. Do you remember this thread?
Anyone adjust the IAC before?

It has another one of my boring videos of the spring moving in an IAC when heated on a stove. It also had the procedure for setting the idle with the Throttle Position Sensor. I was looking for that a while back, and couldn't find it.

.

[fenixus]

ah, that plate. my 5s-fe design does NOT have it!
there is no such plate on my California specs (yes, no vacuum line on 2000 5s-fe model) IAC valve, so it's nonadjustable version.

here's the other side (valve upside down and rotated 180 degrees from former position in pics above):

Originally Posted by ajkalian

No kidding. Do you remember this thread?
Anyone adjust the IAC before?

It has another one of my boring videos of the spring moving in an IAC when heated on a stove. It also had the procedure for setting the idle with the Throttle Position Sensor. I was looking for that a while back, and couldn't find it.

.

[hill8570]

Originally Posted by fenixus

god damn it! it's bad!!!

when I jumper the upper pair (+B and ISCC) it tries closing briefly (it doesn't click, but I feel it vibrates trying doing something), but then immediately returns to half open position if I keep it energized and stays there.

when I jumper the lower pair (+B and ISCO) it doesn't do anything at all ...

... shit ... crap ... junk.

part is original Toyota (JAPAN) with part number imprinted on one side. Other side carries the name Aisan (if reading correctly that type face).

Y'know, I gotta wonder if the part is really defective. I'm working off of a 1999 FSM for the Gen4 (my subscription to TIS is expired at the moment), and it doesn't mention a Cali / non-Cali IAC. I wonder if the 2000 Cali changed the IAC design. I've seen descriptions of something called a "duty cycle air control valve" that Toyota supposedly used in some engines -- it was a two-terminal device designed to be "pulsed" at about 10Hz -- one side was held at 12V, and the other side pulsed to ground -- the larger the % of "grounded" time, the less the air control valve was open. Your valve sorta-kinda sounds like that beast.