After having changed out in-tank pump & checking for normal operations(volume & line between the pumps flow restrictions, I proceeded to replace the main pump. Both pumps are OEM type from Volvo. Once everything was connected, the car was started, and within a few seconds, the main pump began making noise. Bear in mind that the original main pump lasted almost twenty years & never made any noise except for cycle during cranking. Now I can hear the pump cavatating while I am driving above the road noise. Consultation with my parts supplier & the local parts salvage place here in ATL have yielded no help, only guesses.I spoke with Steve Seekens of VCOA fame, & he thinks that the check valve on the output side of the main pump has failed. This would explain why I have had problems over the years cranking the car, since the line would have drained back to the tank each time the engine was switched off, but it would seem once the pump had established the working pressure during engine operation, then the cavitation would not be present.
Any experienced opinions would be greatly appreciated. Also, what is the proper CO setting supposed to be for the F21 turbo in order not to surge at idle during cold wx warmup operation? Thanks to anyone with the answers.
Jerry M. Carter e-mail CAR544TER@aol.com