Please help with a sound.

I am getting a random very high pitched whining sound in my truck. It is random and only does it with the ignition on run, NOT on acc. It is the kind of sound that reminds me of ringing in my ears, only very high pitch. It is only detectable with the radio off but I can hear it over the engine. Then it will stop whenever it feels like it. I got it to do it with my mechanic in the truck, but he is to old and cannot hear that range of sound.It's not a fuel pump as it continues past the time out. It's not the radio as I have tried it with it off. The truck runs fine and no check engine light. It only does it on RUN/ON. Anyone had this happen to them? Any ideas?

 

if you can match the pitch exactly while you're driving, it'll cancel out and go away.

sometimes, for fun, I'll try to harmonize with it using a 3rd or 5th. also, try a harmonic or melodic key.

 

Most likely the smog pump. The smog pump on my truck makes a similar noise, although I'm not sure how high frequency the noise is since I don't hear those so well either

 

It does it with the engine off as well. Just the key on will allow it to happen, and never on acc.

 

I asked the dealer to listen to it when i first got my truck, and they identified it as the smog pump. They also said it is common to hear it after the truck is shut off.

I suppose it could be something different in your case, especially if it's a new noise that you just noticed.

 

did you have the same thing going on? it will do it with just the key on/engine off. I don't know how the smog pump works on this truck.

 

Yes, according to the dealer, the smog pump will sometimes operate with only the ignition on and/or may continue to operate after the engine has been shut off. Which is exactly what I have experienced with my truck.

At the time, I took their word for it since it was under warranty. It's behaved the same for 4 years now with no ill effect.

Of course, like I said, if it's something that just started happening it might be worth it to have someone (dealer; trusted mechanic) take a listen.

 

yes thanx, I will. Problem is my guy can't hear it.lol Is the smog pump electric? another on here said there were no smog pumps 2005-2011, but I have no clue at all.

 

I'm really not sure. But if there aren't any on 2005-2011, then the dealer here is totally full of crap