Idle Control Valve
10-21-2010, 05:15 PM
#1
AudiWorld Member
Thread Starter
Join Date: Mar 2007
Location: Charlotte, NC
Posts: 539
Likes: 0
Received 0 Likes
on
0 Posts
Idle Control Valve
Car has idle bump. Checked vacuum lines and removed and cleaned per the Kris Hansen Audi pages. Performed the Output Diagnosis Test Mode function 03 to trigger the IAC valve per the Bentleys manual. Here's the deal. Is the entire shiney cylinder in the valve suppossed to move? What I have is just the spring inside the cylinder is moving. I have a quality multimeter on the way to test the resistance of 7 to 11 ohms.
10-22-2010, 05:51 AM
#5
AudiWorld Member
Join Date: Mar 2010
Posts: 466
Likes: 0
Received 0 Likes
on
0 Posts
Only major differences between the AAH and the AFC are in (I believe) oil delivery routing.
Peripherals and controllers like the ECU, ICV, etc. are (I'm positive) identical. I don't feel good about your issue at all (sorry). On my AFC, the entire cylinder in the ICV moves. It's the freely-sliding cylinder that adapts to the changes in fuel/air draw under load. One end of the SPRING is (I believe) supposed to be afffixed to the inner wall of the ICV, in order to provide a "default" return position/tension for the cylinder (logically, in the "center" of its range of movement).
PLEASE NOTE:
Though I whole-heartedly agree with Kris's overall procedure, we're a few years later, and a few years harder on our vehicles and their components (yeah, generalizing, I know). IMHO, it's important that you allow 1-2 hours in order to soak the innards of the ICV in P-Blaster first to dislodge all dirt and corrosion. Then, clean/rinse it out with the thinner WD-40.
The tendency of WD-40 to evaporate/break down over the long haul led me to believe that I would end up dry and "hitchy" again within about 6 months. So I put a small (3-4 drops) amount of "3-in-1" brand sewing machine oil into the ICV and gently sloshed it around in order to let it mix with the last bit of WD before pouring it out.
I know that this is excessive. I also know that your ICV is likely broken as opposed to dirty. But do it with your next one before you install it, especially if it's pulled from a bone-yard. You'll thank me 50,000 smooth-idle miles later.
Cheers,
LG
Peripherals and controllers like the ECU, ICV, etc. are (I'm positive) identical. I don't feel good about your issue at all (sorry). On my AFC, the entire cylinder in the ICV moves. It's the freely-sliding cylinder that adapts to the changes in fuel/air draw under load. One end of the SPRING is (I believe) supposed to be afffixed to the inner wall of the ICV, in order to provide a "default" return position/tension for the cylinder (logically, in the "center" of its range of movement).
PLEASE NOTE:
Though I whole-heartedly agree with Kris's overall procedure, we're a few years later, and a few years harder on our vehicles and their components (yeah, generalizing, I know). IMHO, it's important that you allow 1-2 hours in order to soak the innards of the ICV in P-Blaster first to dislodge all dirt and corrosion. Then, clean/rinse it out with the thinner WD-40.
The tendency of WD-40 to evaporate/break down over the long haul led me to believe that I would end up dry and "hitchy" again within about 6 months. So I put a small (3-4 drops) amount of "3-in-1" brand sewing machine oil into the ICV and gently sloshed it around in order to let it mix with the last bit of WD before pouring it out.
I know that this is excessive. I also know that your ICV is likely broken as opposed to dirty. But do it with your next one before you install it, especially if it's pulled from a bone-yard. You'll thank me 50,000 smooth-idle miles later.
Cheers,
LG
Last edited by Loudgoldwing; 10-22-2010 at 05:54 AM.
10-22-2010, 09:15 AM
#6
AudiWorld Member
Thread Starter
Join Date: Mar 2007
Location: Charlotte, NC
Posts: 539
Likes: 0
Received 0 Likes
on
0 Posts
Just to clarify, your cylinder moves when you do the Output Diagnostic test with the vag-com? There is a warning not to try to move the cylinder (bentleys calls it a rotary slide in the warning) with a screwdriver or something that could scratch it. I gave it a try with a piece of plastic and no movement occurred. I'm going out of town and the car is going back to college so it'll take a couple of weeks before I put the p-blaster on it and see if it will loosen up. $310 at Audi, and about $175 online, so this will get worked until there is no hope. Thanks.
10-22-2010, 10:03 AM
#7
AudiWorld Member
Join Date: Mar 2010
Posts: 466
Likes: 0
Received 0 Likes
on
0 Posts
No. I could have sworn that this is a vacuum-actuated part.
If the idle drops, so does vacuum, which allows the sprung cylinder to hit the near-stall signal, triggering the engine management system to compensate. If sticky or locked, a drop in vacuum pressure will go unnoticed because the cylinder isn't moving enough to hit the "DANGER" switch... You know what I mean?
I personally used a nylon cable tie to test the freedom of movement in my cylinder. But it REALLY shouldn't take much to move it. If your spring moves, but not your cylinder, I repeat my opinion about it being broken, not just dirty.
If the idle drops, so does vacuum, which allows the sprung cylinder to hit the near-stall signal, triggering the engine management system to compensate. If sticky or locked, a drop in vacuum pressure will go unnoticed because the cylinder isn't moving enough to hit the "DANGER" switch... You know what I mean?
I personally used a nylon cable tie to test the freedom of movement in my cylinder. But it REALLY shouldn't take much to move it. If your spring moves, but not your cylinder, I repeat my opinion about it being broken, not just dirty.
Trending Topics
10-22-2010, 10:09 AM
#8
AudiWorld Member
Join Date: Mar 2010
Posts: 466
Likes: 0
Received 0 Likes
on
0 Posts
Here's a link for a ICV. ($59.99)
I know it's an ebay listing, but I've bought from these guys before and they CAN BE TRUSTED.
if the link doesn't work (didn't for me) try the ole' "cut-n-paste"
http://cgi.ebay.com/ebaymotors/ws/eB...category=38634
I know it's an ebay listing, but I've bought from these guys before and they CAN BE TRUSTED.
if the link doesn't work (didn't for me) try the ole' "cut-n-paste"
http://cgi.ebay.com/ebaymotors/ws/eB...category=38634
Last edited by Loudgoldwing; 10-22-2010 at 10:15 AM.
10-22-2010, 10:59 AM
#9
AudiWorld Member
Thread Starter
Join Date: Mar 2007
Location: Charlotte, NC
Posts: 539
Likes: 0
Received 0 Likes
on
0 Posts
There is no vacuum hose connection on my ICV. Vacuum may have some input into it's operation somewhere in the ECU logic, but not direct actuation. Mine is a VDO, audi part number 078 133 455A and according to Audi, was used in several models. I have a pull-a-part nearby that has a couple of Audi 100's that used the same ICV, so when I get home, it's off to the junk yard. If mine does respond to p-blaster, a back up couldn't hurt if it is cheap. If you are able to move the cylinder with a zip tie, then mine is probably frozen in position.
10-22-2010, 12:47 PM
#10
AudiWorld Member
Join Date: Mar 2010
Posts: 466
Likes: 0
Received 0 Likes
on
0 Posts
I'm obviously losing my mind, Hub... I'm sorry. I'm going to take a good look at this when I get home. Maybe I'm getting my memories crossed with the ML or an old Saab 900 or something...