140 amp alternator voltage output issue

[SpeednV6]

I've had this Impala SS alt. on for about a year now. I get 13.1-13.5 VDC at idle, the same voltage that I had with the stock alt. How can I get around 14.1 consistantly? Is there any trick wiring that I can do or is this a bad unit?

 

[SpeednV6]

Update:

I replaced the ECM and ECM/Sol. fuses from 10 to 20 AMP. I actually gained voltage output to 13.5-13.9 volts. My issue is still unresolved.

I decided to check the alt. and battery and Scanmaster readings. The Scanmaster is different from the other readings.

At idle:
Battery: 14.2-14.5
Alt: 14.1-14.2
Scanmaster: 13.2-13.7

Why is the Scanmaster different?

 

[QUIP'6']

scanmaster will read slightly lower than scantool since it has to run its course through the ecm wiring also i got a alternator from napa STOCK ONE and i get 14.1 most of the time except when light are on i get13.8

 

[TurboDave]

scanmaster will read slightly lower than scantool since it has to run its course through the ecm wiring also i got a alternator from napa STOCK ONE and i get 14.1 most of the time except when light are on i get13.8

It's not just the rest of the ECM wiring. By the time the voltage makes it's way to the ECM (drawn down by wiring resistances, etc.), it then enters the ECM and is read, and converted to a digital word, then output to the scan tool.

Remember, the scan tools plugged into the ALDL ports are not reading ANY raw info (like voltages, etc.) they are reading converted data words/streams.

 

[QUIP'6']

scanmaster will read slightly lower than scantool since it has to run its course through the ecm wiring also i got a alternator from napa STOCK ONE and i get 14.1 most of the time except when light are on i get13.8

i meant to say scanmaster will read slightly lower than alternator not scantool

 

[TurboDave]

My point exactly. Scan tools will always read substantially less than the actual system voltage (when measured at the alternator or battery).