IACV and air regulator never fully closed?

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mt2forty
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IACV and air regulator never fully closed?

Post by mt2forty »

Hopefully an absurd question with a simple answer (that I can't find on any forum or figure out myself).

My IACV and air regulator are open, so I can't do a proper boost leak test, as all the air just flows into the intake manifold. How do I close them so that I can boost leak test?

I'm assuming it's possible to get them fully closed, as I've boost leak tested the car before with the same setup...

Few notes:
- I just cleaned both the IACV and air regulator - so they both function fine.
- Have been testing the wiring and sensors and they all appear to be fine (except the tps, which I'm replacing)

Thanks in advance for any help!
wannabethestig
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Post by wannabethestig »

Your throttle body doesn't fully seal either. You have to make sure that the intake and exhaust valves aren't open at the same time. Just turn the crank a little bit.
My wife "haven't you spent enough time and money on that car yet?" my answer "no"

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240sxfan6882
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Re: IACV and air regulator never fully closed?

Post by 240sxfan6882 »

mt2forty wrote:Hopefully an absurd question with a simple answer (that I can't find on any forum or figure out myself).

My IACV and air regulator are open, so I can't do a proper boost leak test, as all the air just flows into the intake manifold. How do I close them so that I can boost leak test?

I'm assuming it's possible to get them fully closed, as I've boost leak tested the car before with the same setup...

Few notes:
- I just cleaned both the IACV and air regulator - so they both function fine.
- Have been testing the wiring and sensors and they all appear to be fine (except the tps, which I'm replacing)

Thanks in advance for any help!
Just block off the idle-air tube that connects to the IACV and air regulator with a 5/8 piece of ruber hose that you plug with a big-bolt and some metal worm clamps. That's how I do mine.
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schmauster920
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Post by schmauster920 »

Without blocking anything the air shouldnt go anywhere unless you have leaks, big cams or cam timing issues


It all goes into the motor so even if the IACV is open it doesnt matter as long as you test from the turbo intake

Is the 'air regulator' emissions?
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wannabethestig
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Post by wannabethestig »

schmauster920 wrote:Without blocking anything the air shouldnt go anywhere unless you have leaks, big cams or cam timing issues


It all goes into the motor so even if the IACV is open it doesnt matter as long as you test from the turbo intake

Is the 'air regulator' emissions?
I mostly agree.
My wife "haven't you spent enough time and money on that car yet?" my answer "no"

The build thread-> viewtopic.php?t=58421&highlight=
mt2forty
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Post by mt2forty »

schmauster920 wrote:Without blocking anything the air shouldnt go anywhere unless you have leaks, big cams or cam timing issues


It all goes into the motor so even if the IACV is open it doesnt matter as long as you test from the turbo intake

Is the 'air regulator' emissions?
Car is at TDC right now with stock cams...so air shouldn't be getting through the valves.

I don't have any leaks other than directly through the IACV and air regulator. If I plug off the hose that runs from my hot pipe into the IACV, it holds boost no problem.

I suppose it's possible that the intake manifold is leaking and I missed the leak somewhere, but I checked it pretty thoroughly.

Air regulator is the temp-based regulator for cold starts. It branches off the IACV hard line in the intake manifold.

Is the IACV always open to some degree?
wannabethestig
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Post by wannabethestig »

Yes. If the throttle body is fully closed and no air could get into the engine how would it run at idle? When you adjust the iacv it raises and lowers your rpm because it controls the amount of air that gets in there.
My wife "haven't you spent enough time and money on that car yet?" my answer "no"

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schmauster920
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Post by schmauster920 »

Its not a sealed system the TB is cracked and even if it wasnt the IACV is controlled by the ecu.... The cold start would be open if it was cold but that wouldnt matter

the IACV hose on the intake is after the turbo inlet, you dont boost check from your throttle body unless you dont have boost, then its just a vac leak check like shops do
Last edited by schmauster920 on Mon Mar 11, 2013 9:27 pm, edited 2 times in total.
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mt2forty
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Post by mt2forty »

wannabethestig wrote:Yes. If the throttle body is fully closed and no air could get into the engine how would it run at idle? When you adjust the iacv it raises and lowers your rpm because it controls the amount of air that gets in there.
Word. Thought there might have been a chance the valve was closed unless it was getting power or something. Thanks.

Must be a leak in the manifold or that air is getting past the valves then.
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