The programmer does not change the physical dynamics of the system but it does use more fuel. If you going to 500+ RWHP then your approaching an 80% increase in power which demands a lot more fuel.
It comes down to the amount of fuel that's available. Volume is the issue. If more fuel is used than what is supplied there will be a pressure drop at the high pressure pump intake. Starving this pump is going to damage it. I understand your theory that the pump will not be damaged but I must disagree there. Many a good pump has been damaged by lift pump failure. I see no reason to believe this pump is any different.
By installing a gauge there these problems can be ignored completely.
When I put a fuel pressure gauge on the intake to the injection pump on my other truck I found that the pressure drops to 0 psi. That pump needs 3 psi to function properly. It will run without any lift pressure but will be damaged.
The fact that it can handle 24 psi means nothing other than you need to make sure any lift pump mod does not exceed that pressure at 0 volume. The pressure at 0 volume is the greatest on a lift pump that is independant of the engine. As the volume increases the pressure will normally drop because the pump can't keep up 100%. The volume of fuel supplied is inadequate whenever the pressure drops below the minimum specified limit.
Hopefully there is no problem but I would still like to see someone put a gauge on it to prove that it does not starve the pump.
Last edited by DavidPhillips : 05-18-2008 at 10:44 AM.