SHOspazz92
Banned
The car was cold and had sat overnight. So, It idled a little high until it warmed up and went to normal idle speed as normal.
Read this post I made earlier, On my thoughts:
-Sam
(SOLVED!) VERY rough Idle.
- Thread starter SHOspazz92
- Start date
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The car was cold and had sat overnight. So, It idled a little high until it warmed up and went to normal idle speed as normal.
Read this post I made earlier, On my thoughts:
-Sam
Jake94MTXSHO
New Member
I had a rough idle at a standstill, turns out my valve cover gasket had disintegrated and 2 cylinders were full of oil. Check your spark plug wells for oil
frosho
WOLFMAN
IIRC he recently did a 60k on this car, so the plug well seals and plugs/wires should be good to go.
SHOspazz92
Banned
We did that in June. Unless there's been something major going on then it should be fine. There's no evidence with the intake off that there's any rouge oil down there or anything.
-Ashley, too lazy to sign in on my own account.
ViPER1313
SHO Member
You say you swapped the IACs, but did you make sure that the ports it breathes through are clean and open? Take a pipe cleaner or flexible wire an push it through the IAC ports until it enters the throttle body.
It has to be something in/on the intake or something you messed with during the job. If the car idled well before you swapped intakes and now it doesn't, you know the source of the problem, now you just need to fix it.
It has to be something in/on the intake or something you messed with during the job. If the car idled well before you swapped intakes and now it doesn't, you know the source of the problem, now you just need to fix it.
93rev2sev
SHO Member
Vacuum leak.
As it begins to idle, the IAB is able to keep up for a while, then it starts closing to lower the idle.
As it closes and the engine speed slows, the vac leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops...and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops... and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops... and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops
Sound about right?
As it begins to idle, the IAB is able to keep up for a while, then it starts closing to lower the idle.
As it closes and the engine speed slows, the vac leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops...and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops... and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops... and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops and the IAB responds by opening back up...as it opens...the engine speed increases and the vacuum leak begins...the IAB responds by closing and as the engine speed slows down the vacuum leak stops
Sound about right?
gmorrell
Never been a noob...
What size fuel pump in the tank? If it's 190 or 255 lph, you may be having low-load fuel pressure creep. Checked the fuel pressure?
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SHOspazz92
Banned
We just had the Fuel pump replaced a few weeks ago because I was worried about it being to large. About 1 engine and 8 years ago this car used to have a SHOshop supercharger on it (It was known as "The Hulk", Formerly owned by the Forum memember "Oz"). I wasn't sure if the PO replaced the possibly to large fuel pump when they De-Supercharged it and put in the 3.2. We just put in a Walboro 155.
Here's a new thing. Shouldn't an SHO die when you pull the plug for the IAC? Well, If I pull the IAC plug when it starts idling really low, The idle smooths out and it Idles PERFECT....umm? Keep in mind, This car has had 2 Different IAC's on it that do the exact same thing.
Also, On the Vacuum leak, I checked for a Vacuum leak on every possible coupler, Vacuum line and intake bolt for a possible leak, Using a propane Torch (Unlit of course!) with it idling rough with no change.
I love SHO's.
-Sam
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jonheese
Used-To-Know-It-All
Wow, typical stubborn car issue...
Any chance of putting the old intake back on (I know, PITA) to test? Of course, it won't be a perfect test, because it's still possible that the culprit has to do with the fact that the intake was removed already (eg. leaky intake gasket), and the problem may not go away just because you swap the old intake back on...
But it would help the troubleshooting if you can swap the old intake back on and the symptom stops... Of course, if that does happen, I still wouldn't know what's left to suggest, but at least it would be narrowed down.
Unless/until someone else comes up with a new idea, we're really kinda scraping the bottom of the barrel here.
If this was an episode of House, I'd suggest Lupus or Sarcoidosis.
Any chance of putting the old intake back on (I know, PITA) to test? Of course, it won't be a perfect test, because it's still possible that the culprit has to do with the fact that the intake was removed already (eg. leaky intake gasket), and the problem may not go away just because you swap the old intake back on...
But it would help the troubleshooting if you can swap the old intake back on and the symptom stops... Of course, if that does happen, I still wouldn't know what's left to suggest, but at least it would be narrowed down.
Unless/until someone else comes up with a new idea, we're really kinda scraping the bottom of the barrel here.
If this was an episode of House, I'd suggest Lupus or Sarcoidosis.
93rev2sev
SHO Member
When the TB is closed, the IAB is SUPPOSED to be the only way the engine gets air. Correct me if I'm wrong, but the IAB is not like VAPS. VAPS stays on it's current setting when you unplug it. IAB needs power to stay open, so when you unplug it, it closes and the engine should stall straight away.
This is another symptom that sounds like a vacuum leak.
Ask James about his old car...the 90 that I own now. It had the exact same problem + it only had 140HP according to the G-Tech. I was not able to make the idle smooth out until I swapped in another engine. I have not torn the old engine down yet either, so I still don't know what the problems were.
This is another symptom that sounds like a vacuum leak.
Ask James about his old car...the 90 that I own now. It had the exact same problem + it only had 140HP according to the G-Tech. I was not able to make the idle smooth out until I swapped in another engine. I have not torn the old engine down yet either, so I still don't know what the problems were.
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SHOspazz92
Banned
Wow, typical stubborn car issue...
Any chance of putting the old intake back on (I know, PITA) to test? Of course, it won't be a perfect test, because it's still possible that the culprit has to do with the fact that the intake was removed already (eg. leaky intake gasket), and the problem may not go away just because you swap the old intake back on...
But it would help the troubleshooting if you can swap the old intake back on and the symptom stops... Of course, if that does happen, I still wouldn't know what's left to suggest, but at least it would be narrowed down.
Unless/until someone else comes up with a new idea, we're really kinda scraping the bottom of the barrel here.
If this was an episode of House, I'd suggest Lupus or Sarcoidosis.
Nope, Unfortunately the new intake has bits and pieces scavenged from the old one. Not possible.
-Sam
What I don't understand is, How could there be a Vacuum leak large enough to let the engine idle perfectly smooth with the IAB closed....and yet you can't here it. Just seems weird to me.
jonheese
Used-To-Know-It-All
That is correct, and should hold true here as long as the throttle stop screw has not been fiddled with.
+1
SHOspazz92
Banned
For sale, 3.2 MTX.
We'll see what happens tomorrow, I'm taking it to my "Mechanic". I at least need some fresh eyes on this thing. Don't worry, He's a long time SHO owner who knows his stuff.
-Sam
We'll see what happens tomorrow, I'm taking it to my "Mechanic". I at least need some fresh eyes on this thing. Don't worry, He's a long time SHO owner who knows his stuff.
-Sam
jonheese
Used-To-Know-It-All
Yeah, it doesn't really make 100% sense, but every now and then, even the right answer doesn't.
Just what the doctor ordered, I say. I often find that the best cure for a stubborn problem is fresh eyes.
frosho
WOLFMAN
You could always pull one off of one of your other cars. It's a pain, but if it was my car, I'd swap intakes to see if the issue is isolated to just one of them.
SHOspazz92
Banned
Video. You can see it idles smooth then goes to shit at about 48 seconds in to the video. Don't mind the flickering gas light, The car is low on gas. (That's not the problem!)
[YOUTUBE]RIekQYq0H9w[/YOUTUBE]
-Sam
[YOUTUBE]RIekQYq0H9w[/YOUTUBE]
-Sam
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SHOspazz92
Banned
SHOMON
95 MTX
If the new intake is powdercoated then you may have to clean some of the powdercoating off where the iac bolts to. Or try running a separate ground for it.
SHOspazz92
Banned
Well, The issue was with the Butterflies. There is either a nick in the surface or they are somehow warped. The gaskets are brand new so I know thats not the issue. It took 3-4 tries of spraying brake cleaner at the rear butterflies to hear a definite change in the idle, then to narrow it down to a specific spot. Once it was narrowed down, we put a little bit of RTV on top of the butterfly assembly (where it meets the tank) and BAM! It idles MUCH better. A temporary fix, but at least we now know what the issue is.
While I was at Terry's (NC89SHO) shop, one of the radiator cores decided it no longer wants to exist, So....now we need a new radiator.
Regardless, I'm glad we got this figured out. Thanks for everyone's help!
-Sam
While I was at Terry's (NC89SHO) shop, one of the radiator cores decided it no longer wants to exist, So....now we need a new radiator.
Regardless, I'm glad we got this figured out. Thanks for everyone's help!
-Sam
St Louis SHO
Rollin' coal
Probably has a piece of old gasket in there... BTDT
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