folex187

What should the intake manifold pressure be at idle on a supercharged s2000? Also, what should vaccum pressure should I have at idle?

Thank you,
Alex

[COLOR=red]Please read my last post

xviper

About 10 to 12 psi vacuum.

folex187

Ok, well then I think I have a problem. I borrowed an obd logger today and my intake manifold pressure reads 5-5.5 at idle. You think I have a leak?

Slows2k

You need to make sure that you are comparing #'s on the same scale.

Most Vaccuum readings are done in in/hg. Boost readings are in PSI, above atmostspheric pressure.

I'm pretty sure my old boost gauge reading was at 19-20in/hg of vacuum (engine at operating temp, idle at 800rpm)

folex187

I'll have to check the scale. The readings are just in units. It displays Intake Manifold Pressure and displays 5-5.5 at idle. I believe I set the pressures to be display in psi when I installed the program. Either way 5.5 is way off even if in/hg right?

Slows2k

Manifold absolute pressure (MAP) will be different.

The Vacuum/boost gauges are calibrated to show atmospheric pressure at 0 on the gauge. 15psi is a approximate atmostspheric pressure #. So a -5 reading in absolute pressure would be pretty close to a 20in/hg on a vaccuum/boost gauge.

What exactly are you using to check manifold pressure?

xviper

I should have mentioned that this is what's indicated on my Autometer boost gauge that's hooked up to the intake manifold via a "T" off the same line that goes to the BOV. It reads +7 psi at 9000 rpm. Under full engine braking, the gauge shows -22 psi.

folex187

I borrowed a box called CarChip. I will post a stream of the output here whenever I figure out how to save it. The data really doesnt make much sense according to my rpms. Let me figure it out.

folex187

I'm going to have to install the program on this computer. The absolute value at 2,200rpm at 9mph was 9.6psi when it logged the P1106 code. Short-Term Fule Trim was 1.56% (whatever that means).

folex187

Alright, tonight after going through everything I got to thinking about my BOV (I am running the Turbonetics Godizilla). Is it possible for a BOV is not completely opening on throttle release therefore allowing the blower to force air in which would reduce vacuum?

After thinking about this I took off the BOV and replaced the stock hardware. The car no longer drops below 700rpm upon throttle release. Do you think I have a BOV problem or did my ECU merely learn to deal with the rpm droppage and fix itself?