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Vacuum Leak?

 
Old Jan 23, 2006, 09:30 PM
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Vacuum Leak?

OK. I'm tired of it. She's had the intake, cams, lots more, and a tune. Why does she try (and succceed at) dying when I lift the throttle sometimes? I was told I must have a vacuum leak. Who knows the vacuum system and can tell me all the hoses/connections to check?

Thanks...
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Old Jan 24, 2006, 05:52 AM
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Check all the hoses that hisss when you do this.............................................. .................................................. ...........................................http://www.vfaq.com/mods/ICtester.html
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Old Jan 24, 2006, 05:58 AM
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Um, that's boost leak not vacuum leak ... they're not the same ... are they??? I didn't think so ...
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Old Jan 24, 2006, 08:18 AM
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Originally Posted by KazzEvo8
Um, that's boost leak not vacuum leak ... they're not the same ... are they??? I didn't think so ...

Wow , just wow

Edit--- to much info

Last edited by matt55; Jan 24, 2006 at 08:24 AM.
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Old Jan 24, 2006, 09:27 AM
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Then WTF is causing the stall/dying? Al told me when he tuned it I likely have a vacuum leak. And I'd boost-leak tested her to 23PSI...

Little help here??
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Old Jan 24, 2006, 09:31 AM
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Your car can die if it has a bad enough vacuum leak. Does your idle jump up and down (may be hard to tell now that you have cams unless they idle good)? you should be able to hear if there is a vacuum leak. Is your bov vent to atmosphere? This could cause some of your issue. Good luck.
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Old Jan 24, 2006, 10:14 AM
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Originally Posted by KazzEvo8
Then WTF is causing the stall/dying? Al told me when he tuned it I likely have a vacuum leak. And I'd boost-leak tested her to 23PSI...

Little help here??
The "vacume" lines see's both vacume and boost

There are vacume lines that runs to silanoids(sp) , after the silanoids(sp) the hoses only see vacume or boost (ie egr system) which could be leaking but i dont think thats your problem due to the silanoids(sp) being closed

So what BOV do you have , other mods?

What rpm is your car Ideaing at warmed up?

Lightweigh flywheel ?

The only thing I can think of that the leak tester will not find is from the turbo to the MAF....

Last edited by matt55; Jan 24, 2006 at 11:22 AM.
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Old Jan 24, 2006, 11:34 AM
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264/272's, Buschur Intake are most likely culprits for idle issues. She idles OK, just lopey. A quick blip of the throttle at idle though can kill it. A somewhat abrupt slowdown can get her close to dying.

I had the APS which is combo recirc/VTA ... I just replaced it with the Forge RS in recirc to eliminate the BOV as the problem.

One REALLY odd symptom is how, at idle, when I drop the hood, she almost dies ... idle drops dramatically and comes back up right away ...

What do you mean a line from the turbo to the MAF? The turbo outlet? That was eliminated with the Buschur LICP. I'm getting boost from the manifold for the MBC with the boost solenoid hoses removed and one short section joining one to the other (didn't have 5/32 caps at the time, do now, haven't put them on yet)...

Anymore ideas? Thanks!
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Old Jan 24, 2006, 11:53 AM
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Originally Posted by KazzEvo8
264/272's, Buschur Intake are most likely culprits for idle issues. She idles OK, just lopey. A quick blip of the throttle at idle though can kill it. A somewhat abrupt slowdown can get her close to dying.

The 2 bend pipe has been know to do that , the 1 bend is spose to be better

I had the APS which is combo recirc/VTA ... I just replaced it with the Forge RS in recirc to eliminate the BOV as the problem.
One REALLY odd symptom is how, at idle, when I drop the hood, she almost dies ... idle drops dramatically and comes back up right away ...
What do you mean a line from the turbo to the MAF? The turbo outlet? That was eliminated with the Buschur LICP. I'm getting boost from the manifold for the MBC with the boost solenoid hoses removed and one short section joining one to the other (didn't have 5/32 caps at the time, do now, haven't put them on yet)..
Anymore ideas? Thanks!
The 2 bend pipe has been know to do that , the 1 bend is spose to be better

Mine does that to with the cone fliter b/c the MAF is more sensitive to loud noises


I meen the intake pipe , when you leaked tested it should have been taken off . So there could be a leak in between the MAF and the turbo (ie the motor is sucking more air than the MAF is "seeing")
BTW I had to rase my idea up to 900-950 rpms(after warm up) to get it to idea better.

.

Last edited by matt55; Jan 24, 2006 at 11:57 AM.
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Old Jan 24, 2006, 12:48 PM
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I have the single bend. NOISE affects the MAF??? *LOL*

I took it off, yes and she's clamped tightly - will doublecheck this evening. Thanks.
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Old Jan 24, 2006, 01:03 PM
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Originally Posted by matt55

Mine does that to with the cone fliter b/c the MAF is more sensitive to loud noises

hahaha...its not the MAF, its the knock sensor.
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Old Jan 24, 2006, 03:01 PM
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Originally Posted by fsugatorbait
hahaha...its not the MAF, its the knock sensor.
No really with the cone fliter+MAF the sound waves from a big v8 , motorcycle loud system... can make are maf act funny and all most stall us out . I belive is was Malibujack that frist brought it up , Ill do some more searching
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Old Jan 24, 2006, 03:06 PM
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Someone on a local enthusiast board mentioned an aftermarket fuel pump overrunning the FPR? Is this something that should be checked, if so how? I'm using the Walbro 255lph HF ...
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Old Jan 24, 2006, 05:03 PM
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What does your boost gauge say at idle? I've got similar problems. I have not done a boost leak test yet. But my idle is at a mere 11-12

-Mike
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Old Jan 24, 2006, 05:40 PM
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Originally Posted by matt55
No really with the cone fliter+MAF the sound waves from a big v8 , motorcycle loud system... can make are maf act funny and all most stall us out . I belive is was Malibujack that frist brought it up , Ill do some more searching

Im almost positive its the knock sensor tripping out.
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