ZR1 - Why Tune Reads Fixed Pump?

[06300CSRT8]

Why does the stock tune on a ZR1 show the pump type as "fixed" and have the duty cycles all set to 90% in the pump duty cycle table? We know the pump is variable and duty cycle is used to raise and lower pressure depending on the flow mode.

Is it that the FPCM isn't yet cracked or allowed to be read/write? I noticed the same thing for the 09+ CTSV reads.

[JBZ]

I donno but ive wondered the same thing about the CTS-V pumps and I can tell you that it does modulate to maintain the fuel pump based on 3 fixed values (set points). for the V its 50/60/65 psi based on boost/rpm/and some other factors that I cant recall.

[DSteck]

The ECM isn't controlling the pump, so it would treat it as fixed and let the FPCM do the work.

[06300CSRT8]

Thanks, and so as it looks we have no control or way to monitor what the FPCM is actually doing?

[SilverBullet6.0]

I'm interested in this as well. I have a turbo on my 2010 5.3 truck. I have an 09 6.2 fpcm flashed with a 2011 cts v vin. That combined with a walbro 450 in my stock flex fuel bucket stopped my pressure drop under boost, but once it goes above 10-11psi, the fpcm raises my fuel pressure to 70-80psi which is throwing off my open loop ve tuning.