ZR-1 Net Registry Forums - View Single Post

A26B · 11-11-2015

The vacuum pump provides supplemental vacuum to the secondary port throttle (SPT) system. Vacuum is also provided from the engine during normal operation. If your SPT system is tight, i.e. no vacuum leaks, it will hold the SPT system open for a short romp. When you let off WOT, engine will again provide vacuum.

With vacuum leaks, SPT will not open at all or slowly close, depending on severity of leak.

11-11-2015	#6
A26B Join Date: Dec 2003 Location: Arcadia, OK Posts: 3,404	Re: Vacuum pump confusion The vacuum pump provides supplemental vacuum to the secondary port throttle (SPT) system. Vacuum is also provided from the engine during normal operation. If your SPT system is tight, i.e. no vacuum leaks, it will hold the SPT system open for a short romp. When you let off WOT, engine will again provide vacuum. With vacuum leaks, SPT will not open at all or slowly close, depending on severity of leak. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.