[Diy_efi] MAP vacuum signal isolation?

[pparaska at comcast.net]

I'm running a Megasquirt-I with a Holley Pro-Jection 4bbl TBI.

I've been grabbng the vacuum signal off of a line from a full
time vacuum source on the front bottom of the TBI (below the
throttle plates.  I share that source with a vacuum advance can
on the HEI distributor, through a T in the hose coming from the
port on the TBI that splits off to the MegaSquirt's MAP sensor
and also to the HEI vacuum advance can.

Is there a problem with this kind of setup?  Could I be
getting strange signals to the MAP sensor while the
vacuum advance can is changing it's volume (diaphram
moving)?

In general, is it better to feed the MAP a signal straight
from a manifold plenum that is removed in distance from
the power brake booster and other vacuum ports (Vac
advance, etc.)?

TIA,
Pete
http://AlteredZ.com