Date: Mon, 21 Sep 1998 21:19:10 -0600 From: "Andrew BW Colfelt" <abwcnopsamspring.com> Subject: Re: Vaccum Problems with brakes and turbo?
Just to add to this, the turbo needle measures intake manifold pressure, which can be negative (white) or positive (yellow). From idle until you get boost, intake manifold pressure is negative (a vacuum). Boost is, by definition, positive pressure. The little white zone between the yellow and the white shows dead neutral (zero relative to atmospheric) pressure. Ywan Mason wrote in message <3605D4F2.B53F5A37nopsamsouth.net>... >The needle shouldn't go all the way to the left unless you are closed >throttle decelerating from high rpm. It may not reach the bottom then. >When you turn the car off, there is no intake vacuum so, the needle >should read at the line between the white and yellow, atmospheric >pressure. Under idle, it normally sits about half of the white area or a >bit less.