MAF meters and open-loop.ABout

[Jason_Leone at amat.com]

<<So maybe it is stopping at 5 volts and can't go any higher with more air
flowing through it?>>

You answered your own question. The Mass Air system is not ideal for
forced-induction. In fact, it's pretty damn limiting. The MAF sensor can
only put out 5V and that's it. It's really easy to max it out when you blow
through more air, and even draw through more air. It just depends on the
MAF housing diameter,intake plumbing of the vehicle, turbo characteristics,
and the air flow velocity that cooling the MAF platinum wire.

In my experience with late model VWs, the Bosch Motronic system MAF sensor
gets maxed out at about 8psi worth of boost on a VR6 (and the factory
in-tank Bosch pump maxes out at 8psi on a VR6 too!).
The Motronic system has a little tolerance to play with, by I don't know
about your Hitachi engine management system. You eventually reach the point
at which the MAF system has to be replaced, or modified. You've reached
that point, welcome to the club.

You have a few options here:

1) You can get an aftermarket MAF sensor (from Split Second, etc.) and have
a custom chip done (hey, go w/ larger injectors too)....or

2) You can use something like an HKS Vein Pressure Converter (which uses
Speed Density, but sends a bogus MAF signal to your factory ECU)...or

3) Get serious about life, and get the real deal Speed Density based system
(TEC II, DFI, etc.).

4) Try lowering your boost

Concerning the A/F ratio:

Have you done the necessary fuel requirement calculations to ensure your
fuel supply is capable? Do you know the fuel pressure at the rail, the fuel
pump delivery specs(and the Voltage at the pump), injector flow specs (at
what test pressure), and the potential hp output at full boost? All these
things need to be calculated in order for you to know if you have the fuel
available....otherwise...you will run lean up top, and BOOOOOOM! Bye-bye
pistons!

Jason
'93 Corrado SLC
 w/ Electromotive TEC II