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Generation III Internal Engine
vacuum question

Generation III Internal Engine 1997-2006 LS1 | LS6

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vacuum question

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Old

Jun 28, 2012 | 07:36 AM

#1

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vacuum question

i got my 6.0 lsx engine in my car finaly and got it running, its an iron block with forged internals, but nothing is done to the engine performance wise (no cam yet), but it does have a car intake. now i seem to have a low vacuum issue, my readings are about 10-15"hg and im not sure what the ls engine usually are. if i do a snap throttle test with it on it defonitly does jump up to over 20+"hg

can somebody help me out with what i should be seeing
i do know that my idle is a little unstable because i havnt finished with adjusting the IAC counts, i am just waiting for my solus ultra to come in to finish. could this be my issue?

thanks
mike

Old

Jun 28, 2012 | 09:23 PM

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at idle:

10-15"Hg VAC = 5-7.5psi VAC = 7.5-10psi MAP = 50-67kPa MAP

looks ok if you're running a cam;

Old

Jun 28, 2012 | 09:24 PM

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stock cam would be:

35kPa MAP = 5psi MAP = 10psi VAC = 20"inHg VAC

Old

Jun 28, 2012 | 09:38 PM

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Still running stock cam. Iac counts were at zero so I need to adjust that... Would that help with the vacuum?

Old

Jun 29, 2012 | 08:12 PM

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IAC count at zero means PCM is seeing too much air so it is trying to close up the IAC...

this is a symptom of a leak.

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Jun 29, 2012 | 09:03 PM

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Quote:

Originally Posted by joecar

stock cam would be:

35kPa MAP = 5psi MAP = 10psi VAC = 20"inHg VAC

Interesting...my '01 LS1 with '02+ LS6 heads and cam pulls 29-30KPa on the MAP at 800rpm idle.

Old

Jun 29, 2012 | 09:21 PM

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What is the elevation at your geographic location...?

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Old

Jun 30, 2012 | 05:43 AM

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Quote:

Originally Posted by joecar

What is the elevation at your geographic location...?

285.18m

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Old

Jul 1, 2012 | 01:39 PM

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From: new castle delaware

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y sure theres no leaks, but the throttle plate might be open too much...ill have to wait for my scanner to re-chec what going on

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cam, cammed, cars, counts, engine, hg, iac, low, ls1, ls376, ls6, lsx, psi, vacuum

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