ezrider72 Posted February 26, 2011 Report Share Posted February 26, 2011 I have decided to remove all the vacuum lines in order to eliminate issues during troubleshooting. I am not worried about emissions testing. But I cannot figure out what these vacuum switches do, they just tee into other hoses. Quote Link to comment
Logical1 Posted February 26, 2011 Report Share Posted February 26, 2011 Year?/Model? Pictures are great but other info would help! Oh and welcome :) Quote Link to comment
Skib Posted February 26, 2011 Report Share Posted February 26, 2011 looks like a NAPS-Z 720? Quote Link to comment
datzenmike Posted February 26, 2011 Report Share Posted February 26, 2011 Top right is the altitude compensator, it adjusts the jets to prevent an over rich condition with altitude, just in front is the boost control unit. It reduces high manifold vacuum on deceleration and prevents oil loss past rings and valve seals. Top vacuum switch is for the fuel shut off on deceleration. It saves gas. The bottom one is the spark switching control to run single or dual plugs. With the exception of the spark switching control these all promote better running and economy while having no effect on performance. . Quote Link to comment
Sealik Posted February 26, 2011 Report Share Posted February 26, 2011 .....as stated above.... :D Quote Link to comment
ezrider72 Posted February 27, 2011 Author Report Share Posted February 27, 2011 Yeah, I guess some info on the truck would be helpful. Had a brain fart. '84 720 xtended cab 4x4. I am going to repost new photos with the parts numbered, in order to identify which is which. Thanks much for the info, so far. Quote Link to comment
ezrider72 Posted February 27, 2011 Author Report Share Posted February 27, 2011 Switch 5 tees off of brake vacuum. It has nothing to do with brake lights, unless I have been driving around with out them. The wires were disconnected for a long while before I noticed them. Quote Link to comment
ezrider72 Posted February 27, 2011 Author Report Share Posted February 27, 2011 First pic...on left....boost control valve Bottom right.....vacuum switch. No clue on the upper....need more info on truck/engine...where do those 3 'hoses' go to? The ones I mentioned can be eliminated...they sense lower vacuum from the engine and shut down the exhaust plugs on acceleration. Also.....disconnect/unplug the white wire going to dizzy...then all 8 plugs will fire...all the time. 83+ Z24... Cruise control...? no cruise, manual tranny. the hoses just tee into other lines, going to carb, manifold or other doo-hickies; hard to tell where each one ends up. one guy, on another site, replaced every hose and measured the old ones out to about 30ft worth of hoses. Quote Link to comment
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