True the ECU will try to compensate for rich or lean conditions via the O2 readings. Only problem is in a lower pressure FI there is less time to compensate for a lean condition during a cycle as compared to a higher pressure FI. The pressure is stock at lower RPMs and loads and during greater loads or higher RPMs where is more fuel is needed, it is available so the engine can get what it needs in a shorter pulse rather than going lean. When I was running an adjustable fuel pressure regulator, to get it to run good at the upper RPMs I had to turn the pressure up, but the lower pressure was too high, to fix the lower pressure the upper PSI was too low. I also found out that the AFPR would not limit the low pressure under acceleration and dropped down to 20 PSI creating a lean condition whereas the stock FPR limited the low to 28 PSI. In doing some research for a problem, I ran across articles about the Digifant that indicate that the system tends to run lean under hard acceleration and in the upper RPMs. I might try this in the near future to see if it helps. Others on the list have reported in the past that they have turned the fuel pressure up to @50 PSI and the engine runs better. Robert |
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