|
These noises are due to alcohol mixed fuels and are inherent to Subarus based on what a Subaru master tech told me (mine was the first BRZ he serviced). I once had an occasional chirp but when I switched to 93 octane ethanol-free fuel, it went away.
From my understanding the TSB replaces the existing HPFP with the same HPFP, correct? Or do they re-install it a different way? My friend is on his 3rd HPFP (replaced twice) and the chirps eventually came back in each instance. He hasn't been using ethanol-free fuel so I believe it's all in the fuel.
My other friend conducted a test. He used 93 octane ethanol-free fuel and had no chirps. Then switched to 93 octane *with* ethanol and the chirp came back. Then switched back to ethanol-free 93 and the chirp was gone.
|