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Discussion Starter #1
Not sure why, but my MAP sensory psi is showing 15psi when my actual boost is at 0psi.

It climbs 1psi as the boost increases- 12psi turbo will be 27psi MAP.

Is this normal?
 

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At idle you should see around atmospheric pressure +- a couple
Check that the hose fom the map to the intake is not split or come off the nipple in the manifold. Remove hose and check nipple is not plugged.

Could be a bad sensor as well out of calibration.
 

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Discussion Starter #3
Thats what I thought. Not sure why its showing high boost at idle.
Almost like the sensor is being fooled by something to show higher boost?
Is that a trait of tunes, show high boost to allow the engine to add fuel without the PCM thinking something is wrong?
 

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He just said that it's normal. 14.7PSI is one ATM. So boost at idle is 0, and you also have an additional 1ATM on the sensor.
 

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There's pretty much no circumstance when you should build more than 1 psi maybe 2 at idle.. Id be willing to bet if you pull the rubber hose off and clean it out and clean out the small fitting, it'll be perfect.. Worse come to worse its a new map sensor. That little fitting gets plugged up quick if you blow your EGR and the water hits the soot.


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Discussion Starter #6
So the MAP sensor is probably clogged/damaged is what is sounds like to me.

The MAP should read the same reference number as turbo boost.
No reason why I should be seeing 15psi on the MAP at idle, while the turbo boost is at 0.
 

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He just said that it's normal. 14.7PSI is one ATM. So boost at idle is 0, and you also have an additional 1ATM on the sensor.
Hmmm, this is what I thought, I see 15 at idle too?

Sent from my phone that somebody didn't help me get.
 

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You are seeing atmospheric pressure. 14.7 is one atmosphere at sea level.
So if you have 30PSI turbo boost, it'll probably show 45PSI. Try it.
 

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i am at 3500 feet above sea level and my MAP sensor reads 13.6
That is correct the higher the altitude the less dense the air is and the lower the pressure. If you were at 5000 ft. it would read even less.
 

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jesilvas is correct at sea level the MAP will always read ~ 15psi higher than boost. as altitude increases atmospheric pressure deceases
 

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most boost sensors will read 14.7 psi less than a MAP sensor reads. One can convert boost to MAP by adding 14.7 psi. One can convert from MAP to boost by subtracting 14.7 psi.


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Discussion Starter #13
That makes more sense. Thanks.
 
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