problems w/ my boost gauge ?

ok here we go im trying to pin this down ,let me know if this is normal or if this needs some tech help here please .i have a auto meter gauge it has the peak button and memory button on it fairly exp.$260.00 i thought i was getting the best .iv got the map hooked to my vac with my meth . heres problem number 1 ,iiv got a vortec s/c w/ a 3.33 pulley stock from factory not touched.when i go up the road i fluctuates w/ my peddle into the boost o -10 psi of boost .i not getting into the boost at all .is this normal i was going 80 up the hway tnight andit was reading 5 lbs of boost if i lightly pushed the peddle it would jump to 10 lbs of boost.#2 when i get into boost it shows like 14-15 lbs of boost whats up here ,i know im probably only really getting 5-7 lbs of boost from factory pulley .oh when it does show vac going down it only showing 10/12at idle psi or so .i only have a small cam i dont think its that at all .its just the gauge is all over i mean just pat the gas and its got 10 lbs of boost .id love too hear any sugg.thanks the wiring was pretty self axplanitory but maybe i screwed up .{no way2wires and a plug}

Sounds like you're not getting a good vacuum/pressure reading through your hose. Someone posted a picture this week of a vacuum fitting that you can dedicate as a reference port for your boost regulator on the s/c. Do you remember seeing it? I think it was on the passenger side of the intake toward the firewall and near the top of the intake manifold. You just snip off the tip of the fitting and then install your vacuum hose. I'd start the engine after cutting the tip off just to see that it's pulling vacuum first. After you move that hose to the new fitting your vacuum boost gauge may have a more dependable reading in the old location since it won't have the bellows pressure from the regulator messing with the signal.

<div class='quotetop'>QUOTE(RedHeartbeat &#064; Jul 7 2007, 03&#58;44 AM) [snapback]98864[/snapback]</div>

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Sounds like you&#39;re not getting a good vacuum/pressure reading through your hose. Someone posted a picture this week of a vacuum fitting that you can dedicate as a reference port for your boost regulator on the s/c. Do you remember seeing it? I think it was on the passenger side of the intake toward the firewall and near the top of the intake manifold. You just snip off the tip of the fitting and then install your vacuum hose. I&#39;d start the engine after cutting the tip off just to see that it&#39;s pulling vacuum first. After you move that hose to the new fitting your vacuum boost gauge may have a more dependable reading in the old location since it won&#39;t have the bellows pressure from the regulator messing with the signal.
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i am using that port and i am routed the same way .but i will say i think im having issues with my meth too so maybe ill see if the port is open enough or if it supplying enough for both meth and gaugre .do you know how much psi of vaccuum i should get too supply the 2 of the adequetely ,or should i say how much should be coming out of the port roughly,ill check it today ,thanks.

You may need to run an 1/16" drill bit through there to get a good flow of air through it. Dedicate that port for ONLY the pressure regulation controller on the S/C. Get the vacuum supply for the gauge from another location that doesn&#39;t have a bellows attached to it. The fuel pressure regulator has a rubber flapper type bellows inside it and when it&#39;s working properly it will be fluttering when fuel demands change. This will cause funny readings on a vacuum gauge. I&#39;m sure I&#39;ll be facing the same issue shortly since I have a vacuum gauge to install on my LS1 intake. I imagine I&#39;ll be drilling and tapping a hole some place for a 1/8" hose fitting to be JB welded into place.

<div class='quotetop'>QUOTE(RedHeartbeat &#064; Jul 7 2007, 11&#58;49 AM) [snapback]98876[/snapback]</div>

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You may need to run an 1/16" drill bit through there to get a good flow of air through it. Dedicate that port for ONLY the pressure regulation controller on the S/C. Get the vacuum supply for the gauge from another location that doesn&#39;t have a bellows attached to it. The fuel pressure regulator has a rubber flapper type bellows inside it and when it&#39;s working properly it will be fluttering when fuel demands change. This will cause funny readings on a vacuum gauge. I&#39;m sure I&#39;ll be facing the same issue shortly since I have a vacuum gauge to install on my LS1 intake. I imagine I&#39;ll be drilling and tapping a hole some place for a 1/8" hose fitting to be JB welded into place.
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so is it ok to drill a new hole for dedicated lines ,id like that ,1 for boost gauge and 1 for meth,1 for bypass on s/c.fill me in .by the way do you work @ allens shop?

Nope, I&#39;m just a shadetree home mechanic and love working on cars and trucks.

You may have a good place to install vacuum ports at the throttle body flange. If you can get 1/16npt fittings with the size vacuum hose you need that might be an ideal location. Pull the TB off, stuff something in the intake to catch the plastic pieces when you break through and then tap for the fittings. I think I may try that myself. I&#39;ve got a ton of stuff to install in my truck now that the rains have stopped for a few days around here. :doh:

thanks alot for the sugg, im going too do that today as soon as i get my truck running ,look at my new post please and see if you can help me out ,thanks