my friends d16z6 is boosted at 12 psi, it has a walbro 255hp, 550 rc injectors, aem fuel rail and aem high pressure filter. First had a stock fuel rail and fpr and filter, was losing pressure so upgraded to aem rail and filter, changed fuel pump to another used one after finding out the bag on the pump was all dirty. What can this be? Anything after 15 psi it loses pressure. It will drop at higher rpms.

 

EE_Chris (11:45 AM 1/2/2007): If the pump is known to be good, try upgrading the power/ground wires going to it. Or rather, measure what the voltage is AT THE PUMP and if it's dropping, then upgrade the wire.
And if that doesn't solve the problem, then maybe the pump is just running out of volume for the pressure you're asking it to make.


bump for some good info from EE_Chris