I have the factory installed boost gauge on my steering column. When I'm at idle I see negative manifold pressure. Now, please correct me if I'm wrong, but the instant I give it any throttle at all shouldn't I at least see equal pressure and a reading of 0 before boost builds? As it is now, I see about -4 psi (I think I'm converting that right) up until I give it a little past 1/4, at which point it hits 0 and it starts to spin up.

I was wondering if my guage could be improperly installed/calibrated.

Any ideas??

Thanks in advance...

 

What you are seeing is normal. Under light throttle and load there will still be some vacuum, as throttle and load are increased the vacuum will decrease, pass through the zero point (atmospheric) and then into positive pressure (boost). When the throttle is released there will be a return to vacuum. Under engine braking conditions (closed throttle coasting) there will be very high vacuum, more than at idle.