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| I'm trying to adjust the boost gauge and it seems to be acting weird. Please help! (Page 2/2) |
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hercimer01
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SEP 21, 06:20 PM
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| quote | Originally posted by Lou6t4gto:
What am I "Missing" here ? A Vacuum/Boost Gauge is Mechanical. how can you adjust it? Most engines (any year) that are running normal (N0 Lumpy Cam) will idle at around 20 PSI vacuum when tuned properly, with a cam with more duration , between 15-17 psi vacuum. |
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I was showing 20psi boost under acceleration. This is an electronic gauge running off of the MAP sensor.
I in a 5 volt sensor circuit. There is a reference voltage from a known ground or in this MAP ground. I had used the dimmer ground plane on the back of the cluster which is obviously different than the ICM MAP ground.
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hercimer01
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NOV 05, 07:50 PM
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I bought an Equus Boost gauge and it does show around 19 vac. at idle and 10 psi boost at WOT.
I think my grounds are wrong or something for the 5v sensors.
I did swap in another known good MAP sensor with no change.
Any one have any ideas?------------------
Project Genisis Lo Budget 3800SC swap
12.840@104.8 MPH Intense-Racing 1.9 rockers, 3" exhaust, 3.4 pulley, ZZP tune and 18 year old tires.
88 Coupe under construction SOLD
88 formula 3.4L 4t60 swap SOLD
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1fast2m4
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NOV 05, 08:22 PM
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thesameguy
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NOV 06, 08:19 AM
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On a fuel injected car, vacuum at idle should be around 18-20 inches. What you're seeing on that gauge seems about right - maybe in the factory application there is a filter to keep it from reading off the gauge?
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thesameguy
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NOV 06, 08:21 AM
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| quote | Originally posted by Lou6t4gto:
What am I "Missing" here ? A Vacuum/Boost Gauge is Mechanical. how can you adjust it? Most engines (any year) that are running normal (N0 Lumpy Cam) will idle at around 20 PSI vacuum when tuned properly, with a cam with more duration , between 15-17 psi vacuum. |
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You're missing that pressure is measured in psi (pounds per square inch), and vacuum is measured in inches of mercury ("/hg) ... 
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hercimer01
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NOV 06, 11:29 PM
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| quote | Originally posted by 1fast2m4:
Mine runs @ -19in, I'd say put a stopper on it and call it done.
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Mine too.
I did put a stopper on it because the boost gauge only goes to + or - 15 but it's driving me nuts. It's not accurate.
The mechanical gauge reads -19 @ idle and +10 @ WOT
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rbell2915
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SEP 15, 07:17 PM
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Did you get this resolved?
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Dennis LaGrua
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SEP 16, 04:27 AM
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I have no idea what Boost Gauge the OP is talking about. I use a Stewart Warner Vacuum/Boost Gauge and it works great. Mine operates off a T on the intake line for the MAP sensor and is mechanical. Knowing the reputation of the instrument manufacturer I believe that the readings are very accurate. ------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "
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