Map sensor bad? Reading high at idle
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My friend has been helping me tune my car and we noticed a problem with the map sensor. The map sensor is saying that i am running 55-60 kpa at idle. Then when I drive down the road it drops to around 40-45. Is my map sensor going bad or is there some other explanation for this?
Thanks
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Originally Posted by bluehawk2
My friend has been helping me tune my car and we noticed a problem with the map sensor. The map sensor is saying that i am running 55-60 kpa at idle. Then when I drive down the road it drops to around 40-45. Is my map sensor going bad or is there some other explanation for this?
Thanks
Thanks
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This is one place were metric units are really nice. ~100kPa is atmospheric (standard) but your specific atmospheric condition is affected greatly by your elevation. 100kPa is sea level, but in Denver you may only see 85kPa.
If MAP reads
0 - 100kPa = vacuum
> 100kPa = boost
Or you can substitute in your kPa value for your specific atmospheric conditions above. No more 10inHg of vacuum here, 7psi there, etc.
If MAP reads
0 - 100kPa = vacuum
> 100kPa = boost
Or you can substitute in your kPa value for your specific atmospheric conditions above. No more 10inHg of vacuum here, 7psi there, etc.
Last edited by ChrisS@sdpc; 01-21-2007 at 09:48 AM.
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Cams depress vacuum / raise MAP especially at lower RPM,
at cruise you are up in RPM and the available overlap-time
that makes for vacuum loss (drawing from both intake and
exhaust, whichever is "cheaper" for pressure) is cut back.
Vacuum =(BARO-MAP) in PCM-world.
at cruise you are up in RPM and the available overlap-time
that makes for vacuum loss (drawing from both intake and
exhaust, whichever is "cheaper" for pressure) is cut back.
Vacuum =(BARO-MAP) in PCM-world.