bimbettocavallo

I recently replaced the HFPF in my 67k miles 2009 T4S.
The car was showing code P1025, but was running fine except once when it went into limp mode for a while until I restarted the car.
If I cleared the code, it would reappear after 10-20 miles.
The pump replacement itself was an easy job, getting to the pump was a long process partly due to my inexperience and rusty bolts/nuts in the exhaust area (a few of them broke in the process).
I also decided to completely flush and refill the coolant system using an Airlift.

I haven't seen the error code again after the replacement, but to be fair I haven't driven the car enough yet.
But I started noticing a whining noise coming from the back. I haven't owned the car for long but I'm pretty sure it wasn't there before the pump replacement.
The pitch follows the engine RPM so it must be something that is directly attached to it.

I would be really surprised if it were the new fuel pump. But can it be? It would mean a faulty part.
The other option is something related to the coolant system. Water pump?
Has anyone experienced similar noises?

-Nico.

yelcab

Get a stethoscope and probe around while the engine is running. You could at least isolate the noise to a major component. Water pump is easy to get a probe to.

Petza914

Whining is usually something on the serpentine belt run.

KAGE

This could also be a bad wheel bearing. This recently occurred on my 2007 997. Squeal followed RPMs and came from the rear of the vehicle in my case. I believe my back left wheel bearing went bad. Easy and cheap fix if you have access to the right equipment or an honest mechanic in your area.

Bruce In Philly

+1 on the possible bearing issue and from the belt and its associated sub-systems. I lean to the belt issue because you disturbed that system when you did the pump.

Peace
Bruce in Philly (now Atlanta)

bimbettocavallo

Thanks folks for your inputs.
Bought a stethoscope but nothing obvious I can hear. One observation is that I can only hear it from inside the car, not when I stand behind the engine with the lid open. Weird.

The noise is mostly audible at low speeds (20-30 MPH), at higher speeds it gets drowned in the rest of the engine, tire and wind noise.
I can also hear it when I'm not moving and I just rev the engine. Will a bad wheel bearing justify this behavior?

-Nico.

Petza914

No, a wheel bearing will only make noise when it's rolling and doesn't make a whining sound - it's more a rumbling sound and it will also change pitch or go away depending on which way you turn as the load on the bearing changes.

Odd that you can't hear it from the engine bay. Try turning off your PCM / radio. Noise still there?

weberlukas74

Maybe, check the belt tensioner and idler pulleys. If they're worn or misaligned, they can produce a whining noise that syncs with engine speed. Also, check the condition of the serpentine belt itself.
It potentially could be a vacuum leak. A leak in the intake system or any vacuum hoses could lead to whistling or whining noises.

docdrs

Where did you get your HPFP?

bimbettocavallo

I bought the part from Eurospares while I was in UK two months ago. Genuine Porsche and cheaper (~$1,000) than what they go for in US.