MAP Sensor noise.

[Seth Allen]

> Subject: MAP Sensor noise.
> 
>      It seems that alot of people have used the Motorola MPX4250AP MAP 
>      sensor. What I am wondering is how most people use it. It could either 
>      be mounted under the bonnet with an electrical signal to the 
>      micro-controller, and then you have problems with noise, or it can be 
>      mounted in with the micro-controller, in which case you must run a 
>      pressure signal which could be accidentally cut possibly resulting in 
>      catastrophic boost levels etc. Also there will no doubt be some 
>      (small) delay in increasing the distance from the pressure source 
>      (though this is probably negligable). What is the standard way of 
>      doing this? I am thinking of mounting it under the bonnet, but havn't 
>      decided this for sure. Is there relative advantages/disadvantages? Is 
>      the problem of electrical noise easily solved with a low pass filter. 
>      Any feedback on past experience will be appreciated.
>      
>      Adrian
> 
> 
drian, the knock sening ignition brain on my 1985 golf gti has the MAP 
sensor in in , an that's inside the housing for the brain, I cant 
remember offhand if the case is aluminum or a plastic with a metal spray, 
but I assume that it is in ther to protect it from noise.  The vacuum 
hose is about 1 meter long.  Hope this helps.  I hope the internal 
pressure sensor will handle 12 psi boost.


Seth