"normal" values for OBD2 diagnostics tool

[Cromer]

Hi there,

I have a Autotap scanner which provides all kinds of diagnostic information but unfortunately alot of it is useless unless you know what the "normal' readings should be for the specific vehicle. For example, i have a reading for short fuel trim and long fuel trim... Very nice, but what is normal? same for oil pressure... the value it provides is based on a voltage... i sure would like to know the conversion factor between volts and PSI!!! I have subscribed to the AllData on line shop manuals in the hopes that I could find some data there but it was not really all that helpful.

I am hoping that someone out there has access to a table of "normal" values for:
2004 GP
and
1997 GP GTP

Any values provided would be greatly appreciated..... If enough enthusiasts reply I will create a summary table and provide it back to everyone who is interested.

thanks

[BNaylor]

The short and long term fuel trim feature and diagnostics normally available with Autotap, Powertuners and other full function odb-ii scan tools may come in handy so it is really a good tool. Especially if the fuel injection system is off or you happen to get misfire DTCs. Also, for performance tuning.

The STFT and LTFT values are typically expressed in percentage and the ideal range should be within + or - 5%. Positive fuel trim percentages indicate that the powertrain control module (PCM) is attempting to richen the fuel mixture, to compensate for a perceived lean condition. Negative fuel trim percentages indicate the PCM is attempting to lean out the fuel mixture, to compensate for a perceived rich condition. STFT and LTFT percentages are the adjustments made by the PCM to maintain the 14.7:1 ratio.

Good idea to put it up as a virtual gauge which you can do with Autotap.