Strange noise on 93 E350 ,460 engine.

[brenda]

I purchased a 1993 B190 from my brother who purchased It new.it has a strange noise at times which I can only describe as a WHOOOOOOO sound that comes from the front passenger side of the engine. It will do it at times when you stop and the engine is idleing but if you take it out of gear and rev the engine it will stop. It has done this since it was new but when he took it for service it would never do it.Driving me nuts! Any one had this problem?

[skater]

First, welcome to the forums!

My theory is that the Throttle Air Bypass Valve is bad.

The Throttle Air Bypass Valve (also called the "Idle Air Intake Valve") is a device on the upper intake manifold that allows air into the intake when your foot is off the gas and the engine is idling. The reason I suspect this part is that my '99 Cougar has a similar part, and when it goes bad it makes a noise at idle sometimes described as "moosing" - the noise is caused by something vibrating inside it as the air rushes past - and as you describe, it goes away once you touch the gas.

On the 460, the valve is located on the intake just below where the two large air intake hoses connect, and it faces the front of the vehicle. It shouldn't be too hard to change it, although it may be slightly difficult to reach it just because of the distance. I suspect it'd be easier to change from under the hood, but it may be easier to reach from inside the van with the engine cover removed.

I'm not sure that this is the problem - it's just what I would suspect. And note that you described the noise as coming from the right front, but this part is central (but you might be hearing it from the end of the intake).

There is a cleaning procedure which is basically "use carburetor cleaner", but it says not to use it on "Nipondenso bypass valves" or black plastic bypass valves. I have no idea what Nipo... bypass valve is, or how you'd know whether you actually have one (it should be written on it, but...). There is also a diagnosis procedure but unfortunately I do not have that manual (I have some Ford service manuals for my '91, but not a complete set).

Replacement: RockAuto.com has them starting at $42 and going up to about $80 depending on what brand you buy - don't forget to get a new gasket if you do decide to replace it.

I feel reasonably confident that this is the problem, but remember you're getting a diagnosis from a guy on the internet that hasn't heard the noise, and he hasn't had the same issue with his van, so it's a theory based on general automotive experience rather than specific experience with the problem on a 460. Please let us know how it goes.

[craigmar]

I replaced the idle air intake valve on my 92 Mustang 5.0 engine with fuel injection today, as a matter of fact. The part was $59 plus tax. I did not have the problem you and Skater have discussed but just wanted to say that while the part is only like two bolts holding it in place, the mechanic I took the car to, had to put a diagnostic scanner on the cars computer because he said that when you put a new one on, the cars computer must make new adjustments in order for the part to work right. In my case the readout stated that the battery needed to be disconnected for ten minutes then the car had to be driven for at least 15 miles in order to recalibrate. I don't know if this is something that will affect you if you choose to replace the valve but you might give the dealer or your mechanic a call.

[brenda]

THANKS,WILL CHECK ON THIS PART THIS WEEKEND AND LET YOU KNOW.

[Ernie]

Hi, Brenda.
I have the same problem on my 1993 460. It started about three years ago, at 40K miles. It has gotten worse over time, as now I have 65K miles.

While getting the cruise control recall taken care of at a Ford dealer, I asked a mechanic to listen to it, and he said it was "air pump" and that it would eventually get hard to start and then finally quit running. He also said cost would be about $85 for part and $100 for labor.

While we were talking in the parking lot, a lady drove up in a Ford SUV and had the exact same noise! Mechanic said she had same problem.

I think the "air pump" is same part as Skater & Craigmar discussed above as "idle air intake valve". Please post what you find out, as I plan to repair mine myself before next trip in the spring.

[skater]

I think the "air pump" is same part as Skater & Craigmar discussed above as "idle air intake valve". Please post what you find out, as I plan to repair mine myself before next trip in the spring.

The term "air pump" usually refers to a belt-driven pump that pushes air into the catalytic converter to make it run hotter. And, based on your description, I don't think he was referring to the IAC.

[brenda]

Well,my sorry self finally changed the bypass valve.So far so good.Am going camping in 2 weeks and will post.Not to bad a job .had to remove engine cover to reach the 2 bolts,Had to reach in on both sides.Very tight to get a wrench in.Also had to remove air filter box on front to unplug wire harness on front of valve.needed a small screwdriver to release clip.You might be able to unplug from rear if wires are not as tight as mine were.

[Ernie]

Hey, Brenda
Did the Whoooo noise go away? Any other tips before I attempt to replace my Throttle Air Bypass Valve on 1993 B190? Has anyone just tried to clean the valve instead of replacement?
And Skater -you were correct, the noise would not be from the "air pump", as I mentioned previously).
Ernie

[brenda]

So far so good but have not used it that much yet.

[brenda]

Have been camping quite a bit and the noise has never happened again.