Runaway throttle....hellllllp
Boost could only be holding it open if there is a pressure difference....there wont be when its open because pressure is equal across the blade. When it goes to close there will be aerodynamic lift generated on the blade creating a moment trying to keep it open, but this should be far less than the moment of the spring trying to close it. Have you adjusted it in any way? I think chris is right and if it is opening the full 90* it could stick inside the tb. The difference in area of being opened 85 degrees versus 90 degress is only 0.4%
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Boost could only be holding it open if there is a pressure difference....there wont be when its open because pressure is equal across the blade. When it goes to close there will be aerodynamic lift generated on the blade creating a moment trying to keep it open, but this should be far less than the moment of the spring trying to close it. Have you adjusted it in any way? I think chris is right and if it is opening the full 90* it could stick inside the tb. The difference in area of being opened 85 degrees versus 90 degress is only 0.4%
H9Ukt!~~0_12.JPG)
As you can see, next to her right.... uhhh, thumb... it's notched to let it open more. I wonder if a quick 10x wrap of electrical tape around her bump stop would tell me if that's the problem....
Probably a good thing for NA where there's vacuum, but not so good for FI... hmmmm. Will try wrapping it tonight.
But wait, I don't think my friend's TB bump stop was cut. Will have to ask him.
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I'm going to wrap the bump stop and maybe tighten the spring. The wire spring on the POTZ TB is a little thinner, not necessarily lighter, but maybe tightening it up a wrap or two will help.
Last edited by HRHohio; Sep 10, 2012 at 06:36 PM.
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Hey Fella! That's my wife! 
(Hahaha.. Just kidding! Don't I wish I had access to that!)
UPDATE: Just txted friend. His TB is all stock, not ported, no bump stop mods, etc. When we swapped his on last night, it still did it.
(Hahaha.. Just kidding! Don't I wish I had access to that!)
UPDATE: Just txted friend. His TB is all stock, not ported, no bump stop mods, etc. When we swapped his on last night, it still did it.
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Verdad Gallardo Thread Starter
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My idle air control valve was causing this same concern when it went bad. try unplugging the TPS and idle air sensor on TB...turn the key to on position for about 30 sec, turn off and plug the stuff back in.
I did not read all the comments in here but I can assure you its your lack of a bov
I had the same exact ussue when my bov took a crap on me for about 2 sec the throttle would stay wot
Not very fun when you a twisty tight canyon
I had the same exact ussue when my bov took a crap on me for about 2 sec the throttle would stay wot
Not very fun when you a twisty tight canyon
Last edited by tripblackls1; Sep 12, 2012 at 01:04 AM.
Go look under the hood of a grand national and see for yourself
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Will try to get the BOV back on this weekend. Also, no carpet issues. Checked that already. Also removed the floor mat to rule that out.
Will let you know how things go once the BOV goes back on.
Thanks for the input guys. Not a lot of fun when you can't stop when you want to.
Will let you know how things go once the BOV goes back on.
Thanks for the input guys. Not a lot of fun when you can't stop when you want to.
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It ended up being the black cruise control throttle union piece @ the battery. When the car built boost the pipe was flexing and hitting the black casing, the cable guide is mostly circular but there is a part that is slightly flat that was getting bound up. Upon dissemblance, we could actually see a slight groove in the plastic inside where it was hitting.
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From: Las Vegas, NV
It ended up being the black cruise control throttle union piece @ the battery. When the car built boost the pipe was flexing and hitting the black casing, the cable guide is mostly circular but there is a part that is slightly flat that was getting bound up. Upon dissemblance, we could actually see a slight groove in the plastic inside where it was hitting.
