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IACV function test

G

gorman

Hard-core CEG'er
Joined
Jun 29, 2008
Messages
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Hi guys, i suspect my IACV is faulty. I have taken it off to inspect. With it unbolted, i can see the valve between the chambers is open. With it plugged in, i am switching the ignition on and off, but i don't see the valve moving to close. Should i be able to test it this way ? I checked the fuses 4+9 and relay 11 and i have 12v coming from the green and yellow as expected.
Would someone with a functioning spare IACV, please try plugging it into the loom and see if this test method works...thanks.. G.
 
gorman said:
Would someone with a functioning spare IACV, please try plugging it into the loom and see if this test method works...thanks.. G.
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The IAC default is full-open and that's where it is for start-up, so just turning the key won't tell you much. Keep the IAC unbolted from the manifold but connected to the harness, and have someone start the car. The IAC should begin to close once the car is started, as the PCM tries to bring down the idle.

Why do you think it's bad?
 
hi there; a few weeks ago, the car started to stall all over the place...then it started to stall only when it was cold. Now it's gone back to stalling all over the place. Done all the usual checks. G.
 
I'd have to agree it's probably the IACV. Did you have someone start the car while you were holding & watching the valve? It should go from open to closed smoothly. If it looked like it stuck in one or more places momentarily, you'll need a new valve. Something you can do that will possibly make it better in the meantime is fill it with carb cleaner & let it sit for a while. Start the car again & let the valve go from open to close with the cleaner in it - this will clean and lube the shaft. Do this a few times until the sticking isn't as pronounced, then dump out the cleaner & reinstall the valve. Sometimes this will help, sometimes it won't, but it's free to try if you have any carb cleaner sitting around.
 
SicSE said:
Did you have someone start the car while you were holding & watching the valve? .
Click to expand...
Not yet.it's been a busy weekend.
SicSE said:
Something you can do that will possibly make it better in the meantime is fill it with carb cleaner & let it sit for a while..
Click to expand...
i tried this with WD40 a while back. Gonna check its functioning properly later today... i'll let you know ..thanks..G.
 
ok, get this. I just removed the IACV. I applied 12v across the terminals and the valve..(in its limited movement) ...tried to OPEN the valve. I supposed i had connected the 12v the wrong way round. I switched the wires around and the solenoid is still trying to OPEN the valve, which is held open by the spring anyway ..!!??.. ideas anyone... G.
 
0 volts = default = open valve
12 volts = max open commanded by PCM = open valve
3 volts = nearly closed
You have to regulate down the voltage supplied to the valve. Easiest way to do that is to use the PCM like I suggested... unless you happen to have a voltage regulator handy.
Operating range of the valve is 3-11.5v.
Resistance between valve pins should be between 6-13 ohms.
Resistance of each pin to valve case should be > 10,000 ohms.
 
solenoid resistance 12 ohms ok. Tried it on the car..doesn't move at all. I definately have 12v from the relay...so it looks like i need to trace the black wire back to the pcm. I still think it's odd that connected both ways, the solenoid moves the same way... G.
 
ok, according to the haynes book...the black/yellow wire on the IACV plug goes to pin 21 on the pcm. Looking down in the engine bay at the pins on the pcm, i'm getting a circuit on the 5th pin in, bottom right corner...they aren't numbered, but the wire going there is black/yellow. So, i'll swap it out and see how it goes. thanks ..G.
 
If you're gonna chase a ghost, at least check the right pins. According to the Ford CD's for 96, 98 & 00 Contours, bk/ye goes to pin 83 at the PCM. 21 is CKP+.

Also, if you unbolt the PCM connector, there are numbers on the connector face indicating the first & last pin numbers in each row.
 
,
SicSE said:
If you're gonna chase a ghost
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mmmmm spirit chasers lol ,
SicSE said:
at least check the right pins. According to the Ford CD's for 96, 98 & 00 Contours, bk/ye goes to pin 83 at the PCM. 21 is CKP+..
Click to expand...
Ok cuz, on this side of the pond, it's pin 21 for 95 -00 mondeos.

SicSE said:
Also, if you unbolt the PCM connector, there are numbers on the connector face indicating the first & last pin numbers in each row.
Click to expand...
i looked and looked again ..can't see any. There is one other issue..i have the SVT RJL1 pcm to handle SVT cams and 19lb injectors...make any difference ? ..G.
 
OK, i've just looked at the pcm. If you were to hold the pcm in your hand, so that it says this side up at the top...my black and yellow wire goes to the 5th terminal in from the top left corner. It actually sits upside down in my car because of the connector plug orientation...just thought this might be clearer 'cos of the different manuals...G.
 
gorman said:
i looked and looked again ..can't see any. There is one other issue..i have the SVT RJL1 pcm to handle SVT cams and 19lb injectors...make any difference ? ..G.
Click to expand...
Didn't realize you weren't in the U.S.. The connector is what's numbered over here. The Mondeo harness may not have the connector numbered. :shrug:
 
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