Turbo guage not working properly

Hello,
Just joined I liked what a saw. Anyway, I bought my 87 supra about a year or so ago, and have a turbo issue. At idle my turbo guage is pulled all the way down, I believe it's what? 4 psi. (stock guage) I disconnected the pressure sensor from the vac line and the guage zeros out, so I belive the pressure sensor is good, however cant find a damn thing about them. I also checked the intake manifold, and had about 25-30 psi, which i heard was good. Now, during normal driving, and Imean giving it a little gas, not granny driving, it still doesn't budge, unless I really get on it, even then it only goes up to 6 psi, I believe the guage maxes at 8. Almost forgot, I also reved up the engine when I had the vac/pres tester on the intake and it moved up and down, don't recall what it went up to.

The numers are off alittle bit. The stock exhaust/elbow/DP really cuts down on the flow which is probably why it's not reacting like you want. On top of that the stock boost gauge is very slow to react and not too accurate compared to an aftermarket one, buy one and you'll see what I mean. The 4psi your talking about is 4 hg/in, or vaccume, not boost (psi). A normal 7m will pull around 20-22hg/in so if your really reading 4 in neutral at idle something is definetly wrong with the engine, would have to be a big vaccume leak but that would cause 50 other problems, spray starting fluid around the IC pipes and all rubber hoses while it's running and see if you can find it. What's that reading about 25-30hg/in by the way? Stock boost is around 6psi so that's normal. Also you shouldn't be able to build any boost by reving the engine unless your auto and brake boosting.

Thanks for the advice Project. I see how 4 hg/in would be bad, however that is just what the stock guage is reading. I get about 25 with a manual guage hooked up, so i don't think that is much of a problem, although my rubber hose from the m.a.s. to the turbo leaks a little, but toyota wants like 350 bucks for one. Do you know much about the turbo pressure sensor? if I were to get a manual guage, how would I go about hooking it up? should I just drill another hole somewhere and leave the old system intact? I just don't want the ecm to go haywire. Thanks

If your getting 25 with an aftermarket gauge and the car is running like a dream then your in the clear, nothing to worry about but I'd get a good boost gauge anyway. You leave the stock gauge alone and tap one of the hoses off of the intake manifold, there is one coming off the back that you can put a "T" on and tap from that to the boost gauge. $350 for the stock TID/accordian hose?? That's insane, go to http://toyotaworld.com/ and get one from jeff, should be $32.03 last I checked, brand new. Also, Turbo MKIII's have AFM's for future reference.