Quote Originally Posted by dougmac View Post
I don't believe this to be true and I don't understand the term "complain" as it relates to the pcm. I see no trouble codes that indicate a fault condition exists when "the regulator requirement is greater than expected" and it is not listed as a condition for setting the P0087 trouble code or even mentioned anywhere in the P0087 trouble shooting chart.

Excessive injector spillback is however mentioned as a cause.

What leads you to this conclusion?

There is a LOT of diagnostics going on behind the scenes and it is my belief that most of this is only provided on a need to know basis.



Quote Originally Posted by dougmac View Post
It is completely flawed logic that the pump does not pump to capacity when it sees a pressure below requested condition.

Equally flawed is the statement that it reduces output as a protection mode for the pump. There is less pressure on the internal parts because the the rail pressure is reduced under these conditions. There is more fuel flow through the pump allowing for better cooling and lubrication. This condition is a less stressful to the pump than operating at full pressure with more limited fuel flow.... I am not sure what they would be trying to protect it against?

The pump can move to near capacity, but not full capacity. Additionally, it is controlled by a complicated set of PIDs, expected flow rates, flow limits, etc. These are based on small errors and large errors both positive and negative. These are likely there to provide a smoothing effect to prevent the pressures from spiking and sagging. I will not claim that I can even begin to understand the entire interworkings of these tables, but wheat I will say is that I have had solid success in tuning to help the pump stay on target.



Quote Originally Posted by dougmac View Post



I am supposed to rely the "real world experiance" with their calims that make no sense at all over the GM technical documents? I'll stick with the GM information. I have been in this business long enough to tell the BS from the truth, thank you....
So basically you joined the forum to call BS on me...