What to do about the noise ¿?

[brii]

Hi there, I'm new to the board and glad to have found it! I just bought a '97 X-Sport and discovered a dronning/hum/buzzing intermittent noise which appears when the idle is low; approx. 500 rpm and when lower to be more of a continous off/on dronning/humming/buzz noise. The noise seems to be coming through the steering column and floorboards in the cab as well throughout. I've had the X at the dealership and they troubleshot as much as to say its an engineering design issue. What the dealership did to troubleshoot is listed below; please be aware that I'm not a mechanic and hope what I'm typing about is accurate to understand. Here goes...

1. Re-programmed the computer module (PCM?)
2. Neutrilized exhaust system,replacing u-bolt.
3. Checked the power steering lines, they did notice a pair of lines close together possibly making that noise and tried to give them distance, but were limited to do so. no change, noise still there.
4. Sprayed clean the IAC valve. no change, noise still there.

Oh! I forgot one thing, when I mentioned lower idle, the idling fluctuates between 500 and 700 rpms, the noise gets worst when the rpms are there lowest. I hope all this I'm saying makes sense. Any suggestions and advice is greatly appreciated.

CHeers!

 

[taxx]

Welcome.....

I hate to say it but the dealer may be right about it being a engineering defect. I don't have that problem that I am aware of, but I feel you pain and I know how frustrating it is. But if everything checks out ok and it is mechanically ok, then I wouldn't waste much time/money in it. Truct me on that. You can dump tons of money in and not get anywhere, but back to the start. Although sometimes you get lucky. Maybe someone here will have better tips than I.

 

[TPLYNCH]

My hum/whine at Idle was my IAC. Maybe cleaning wasn't enough. Plus, if your idle is fluctuating that much, it may be an indication that your IAC is going bad. It cost's ~ $70 and you can replace yourself in ~ 15 minutes. Dealer will charge you ~$225. (all figures in USD)

 

[brii]

So the idle doesn't bounce around as much as i mentioned earlier, actually what happens with the idle is when i start the X it goes to an idle of 800 or so and that to me sounds ok, but, after the truck is warmed up, the idle slowly drops down to 600 or so and then drops down again and does a slight dipping from 550 to 500 and thats when this dronning/humming noise starts, especially at the lower rpm. I figured, like you'd mention of checking the IAC valve and having it replaced.

Others have told me too get some fuel injection cleaning fluid and see if that works, and maybe the manifold might be the culprit...hmmm....

Cheers!

 

[topo4u2]

Hello, did anyone check to see if it was your fuel pump making that hum?
Mine does quite a bit and I also noticed the other day that it is real bad if I put my hand on the gas tank sheild. It may be touching the tank slightly and causing a hum through the frame. I may take a look this weekend and put some rubber washers between it and the frame and see what happens.
Just my 2 cents.

 

[dogfriend]

Classic IAC symptoms

Dead Link Removed

Dead Link Removed

Dead Link Removed

and lots of others. Search for IAC.

 

[brii]

Thanks for the links and I'll check out the IAC valve, as well as my fuel pump.

I'm wondering about the gas octane level, would that make the idle act up? I went and filled up once with 89 to see if theres a difference in fuel economy and didn't notice much, but prior to that I was using 87, and then I went back to 87.

Cheers!

 

[dogfriend]

I have a book (Ford Fuel Injection and Electronic Engine Control) that states that you should use 87 octane if your engine runs ok on 87 octane and avoid using 89 octane (or higher) if possible. The reason is because the higher octane grades will tend to build up carbon deposits faster.

I don't think the gas would cause the type of idle problem that you are describing. It has the symptoms of a bad IAC valve.