Fixed my high idle the old fashioned way...brute force
11-23-2008, 02:21 AM
#1
Burning Brakes
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Location: Myrtle Beach, South Carolina
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Fixed my high idle the old fashioned way...brute force
I took a cheap 1/4 inch drive socket I had laying around that has about an 3/16 inch hole through it...slipped a thin rubber cap over it to make it a bit thicker and less slippery and cut the end off the cap so the air can pass through the hole...shoved that puppy like a chrome plated suppository right down the hose that feeds air from the air guide/cowl under the MAF to the inlet of the ISV.
So now the flow of air is restricted by way of that 3/16 inch hole.
After letting it warm up and taking a drive my car now idles at approximately 650 rpm's.
It ain't rocket surgery but it works
So now the flow of air is restricted by way of that 3/16 inch hole.
After letting it warm up and taking a drive my car now idles at approximately 650 rpm's.
It ain't rocket surgery but it works
11-23-2008, 11:15 AM
#4
Wunderbar! On one hand, all for temporary repairs on the cheap.
On the otherhand, if the problem is isolated .... I hope you don't procrastinate indefinitely.
Git' crackin, Craig.
Keep us posted.
On the otherhand, if the problem is isolated .... I hope you don't procrastinate indefinitely.
Git' crackin, Craig.
Keep us posted.
11-23-2008, 12:25 PM
#6
Burning Brakes
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It sits about one inch beyond the 45 degree bend in the hose. Since the engine is under boost I would think the inlet side of the hose will always be under slightly higher pressure than the ISV side, being that the ISV itself will reduce any pressure coming from that end of the tube relative to the inlet side. It's in there with enough friction where I don't think it can move just from momentum or vibration.
And, no, this isn't really my "fix", it's more of a test to prove my theory that something is causing my ISV to open more than the running conditions warrant. Finding that something is proving to be a real pain in the *** and wallet! I hope to leave it in there long enough to drive the car under all conditions and see if anything changes other than the idle behaving.
I originally tried to install a ball valve in the hose so I could dial in the proper amount of air but it proved to be too much without removing the intake so I improvised out of frustration.
I guess it could simply be that the the new ISV was faulty and opens to a greater degree than they are designed relative to the pulse it receives but that seemed like a least likely suspect when this ordeal started...now it's getting a little easier to believe.
Since the next time I take the intake off will be the fourth time it was done to solve this I want to explore as many possibilities as possible so the fifth time is the last time!
And as always I'm open to, in fact begging for, any suggestions, comments and criticism because I want to learn as much as I can about this, so thanks!
And, no, this isn't really my "fix", it's more of a test to prove my theory that something is causing my ISV to open more than the running conditions warrant. Finding that something is proving to be a real pain in the *** and wallet! I hope to leave it in there long enough to drive the car under all conditions and see if anything changes other than the idle behaving.
I originally tried to install a ball valve in the hose so I could dial in the proper amount of air but it proved to be too much without removing the intake so I improvised out of frustration.
I guess it could simply be that the the new ISV was faulty and opens to a greater degree than they are designed relative to the pulse it receives but that seemed like a least likely suspect when this ordeal started...now it's getting a little easier to believe.
Since the next time I take the intake off will be the fourth time it was done to solve this I want to explore as many possibilities as possible so the fifth time is the last time!
And as always I'm open to, in fact begging for, any suggestions, comments and criticism because I want to learn as much as I can about this, so thanks!
Last edited by aggravation; 11-23-2008 at 03:22 PM.
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11-23-2008, 06:06 PM
#8
Captain Obvious
Super User
Super User
Good job!
Interesting that this is pretty much the same fix for the late 90's 24V Ford Duratec high idle problems too. The way I did it on that car was to use a storage hose cap, like the ones junkyards use when storing engines (they are ususally orange), and drilled the required hole in it. Since plastic cap had a lip, it did not allowed it to be sucked passed where it was installed. Here's what they look like and I think it could work well for the S4s too:
Interesting that this is pretty much the same fix for the late 90's 24V Ford Duratec high idle problems too. The way I did it on that car was to use a storage hose cap, like the ones junkyards use when storing engines (they are ususally orange), and drilled the required hole in it. Since plastic cap had a lip, it did not allowed it to be sucked passed where it was installed. Here's what they look like and I think it could work well for the S4s too:
11-23-2008, 06:13 PM
#9
Race Director
Craig
I forgot you were under boost....that does change things....
as my ISV was failing, it would restrict air (lowering idle) more than it should......assuming the new ISV is working normally (it should since they are $300) my next best guess is a vac leak? Did you try a smoke test?
I forgot you were under boost....that does change things....
as my ISV was failing, it would restrict air (lowering idle) more than it should......assuming the new ISV is working normally (it should since they are $300) my next best guess is a vac leak? Did you try a smoke test?
