5.7 GXI-HF making "whistling" noise

[HiWard]

So my engine (or drive?) has developed this high-pitched whistle-like noise. I've done some online research and a lot of posts and videos suggest the fuel pump might be the culprit. My pump has been whining for years, but the pitch is more or less constant, eventually drowned out by engine noise when up on plane.

This new noise will appear at around 1500rpm, but will eventually disappear once I throttle to above 3000rpm. When throtteling down, the noise will reappear and the pitch will increase as I reduce revs and eventually disappear (at least out of the frequency range of my hearing) as I come down to no-wake speed which is at around 1000rpm.

Any thoughts on this? Is it the fuel pump or could it be something else? I removed the paint form inside the fuel cell assembly a few years ago, replaced the high-pressure rail screen with and e-clip and cleaned my injectors this season.

 

[Scott Danforth]

Check the IAC muffler.

However throttle blades do whistle

Take care of the fuel pump wine. That issue will leave you stranded

 

[HiWard]

Check the IAC muffler.

However throttle blades do whistle

Take care of the fuel pump wine. That issue will leave you stranded

Thanks for the input. I wasn't aware there was an IAC muffler on the 5.7GXI ('06 or '07). Seems like something which should be a maintenance item. I'll pull the flame arrestor and have a look.

I have an aftermarket fuel cell lying around, I'll install that and see if the problem goes away.

 

[HiWard]

So my replacement pump was a dud (bought second hand, a gamble on my part). Before I buy a new third-party fuel cell assembly; has anyone experienced this kind of whistling noise at certain rpms? I know the classic whine coming from these pumps, this is something else. Any other potential sources?

 

[stouchton]

I have had some crazy noises from serpentine belts - spraying some water on them can stop the noise temporarily. I had a screech I swore was a bearing - was the belt.

 

[ESGWheel]

A vacuum leak can make a whistling noise.

 

[HiWard]

A vacuum leak can make a whistling noise.

Where should I start looking?

 

[ESGWheel]

I would start with any vacuum hoses. My 2005 GXi-E has 2 vacuum hoses: one that goes from the top of the fuel cell to the intake manifold and another that goes to the regulator fm mid intake manifold. Nos 16 and 25 in the attached diagram.

 

[HiWard]

I would start with any vacuum hoses. My 2005 GXi-E has 2 vacuum hoses: one that goes from the top of the fuel cell to the intake manifold and another that goes to the regulator fm mid intake manifold. Nos 16 and 25 in the attached diagram.

Thank you! Will have a look at these.

 

[Mc Tool]

My old MR2 (aw11)had a high pitched squeal that would come and go erratically .....dry bearing in alt

 

[ChooChooSnakeMan]

So my replacement pump was a dud (bought second hand, a gamble on my part). Before I buy a new third-party fuel cell assembly; has anyone experienced this kind of whistling noise at certain rpms? I know the classic whine coming from these pumps, this is something else. Any other potential sources?

I had to replace the fuel cell (complete - both high and low pressure) on my 2011 VP 8.1 Gi-J last year. I had the high pitch whine and was able to tell with the engine cover up that it was coming from the fuel cell. It didn't whine all the time and I think that at certain engine rpms the engine noise covered it up. I had heard the horror stories of people being left stranded by the paint in the OEM fuel cells. I also heard about a few engines that went boom and about some very expensive fuel injectors that had to be replaced because of the paint. I contacted Troy with ManCaveMechanic and he fixed me up with a reconditioned fuel cell. Troy was great to work with and very helpful. Once I put it on no more whining noise and I'm relieved that I caught it before it got to the injectors. I would think that you should be able to tell if it is the fuel cell by getting down close to it while the engine is idling. Another source for whining could be your belt idler pulleys. I hope you find out what the problem is.