lupus, Fuel pressure
Normal fuel pressure should float about 14-15 PSI running down the pavement. It should never fail below 10 PSI at all. Here is a colorize fuel pressure gauge to give you a clue of the fuel pressure span you want. You want the needle to stay in the green at all times. Yellow zone is a warning that you should check the fuel filter, lift pump performance, overflow valve, etc.
This is undocumented maximum pressure is 20 PSI. Now take notice to the overflow valve is set for 14 PSI so excessive pumping of fuel does nothing for performance except create more heat in the fuel, which in turns reduces the cooling ability of the fuel and adds more stress to the lift pump. So a little extra fuel pressure is a good thing because it insures the Bosch VP44 injection pump stays cooled and lubricated properly. However, excessive fuel pressure will heat the fuel and reduced the cooling ability of the fuel.
Now always remember that the only lubrication the Bosch VP44 injection pump will see is the fuel itself so if you don't have enough fuel pressure it will cause damage to the Bosch VP44 injection pump. It's like the same as running the engine with low oil pressure it will continue to run but the damage to the engine will occur. On the other hand, the Bosch VP44 injection pumps, which happen to be about $1,200 to replace.
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