This is very boring i know but i saw somewhere that if apc solenoid make a tickling sound (on/off) when you hit the brakes is this ok??? i'm not getting boost over basic boost pressure any ideas,.?!?#!)= thank's!
and another question?
I'm installing progressive fuel pressure controller, can i put it after the standard one, or is it better to replace it with the new one??
many many thanks

Hi mate. I am no expert in search things but can tell you that it waqs the clicking sound on my 1990 900 T16 that led to the accurate diagnosis that the APC unit had seen better days! Had the exact symptoms of base boost as you describe. Had a variation of this on my 89 9000 carlsson a couple of weeks ago and changing the black APC unit above the rad cured it in 2 minutes. Then it was all boost and smiles again!! Thats when you slip the Bic pen tuning tip into the middle pipe and watch the neddle edge into the red!! :wink: