I recently replace my 4.0 with a 4.6 stroker. I also converted the TB to 63mm, bored polished and made custom butterfly plate and piped the CAI with filter into the cowl. When driving and you tip into the throttle you get a high pitched tea kettle type whistle that goes away the more you mash the pedal. You get the same thing only different pitch when you back off the throttle. It was cute for a very short while but I drive 6 hours almost every weekend and now its annoying. I have experienced this with Mustang BBK throttle bodies and the old trick was to drill a 1/8" hole in the butterfly. Maybe that will work here as well. Ideas or suggestions?
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XJ whistling since new engine!
- Thread starter nicpaige
- Start date
dan1977p
NAXJA Forum User
- Location
- Virginia Beach, VA
With this and your cruise not working, I'd go with vacuum leak.
RNMedic
NAXJA Member #659
- Location
- Dayton, Ohio
CAI and bored throttle body
dan1977p
NAXJA Forum User
- Location
- Virginia Beach, VA
Oops, I missed that.
VAhasnoWAVES
NAXJA Forum User
- Location
- Lake City, Mi
i have a 60mm throttle body and cone filter... i get a whistle too.
blakews2217
NAXJA Forum User
- Location
- Alton, Illinois
I have a 60mm and cai. I get the whistle at part throttle. It's the air whistling by the blade.
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
- Location
- Hammertown, USA
This is a really common bored throttle body problem.
I've never seen a reliable fix for it.
Not sure that I'd want to drill a hole in the butterfly myself, but i guess if that fixes it.
I've never seen a reliable fix for it.
Not sure that I'd want to drill a hole in the butterfly myself, but i guess if that fixes it.
trippled
NAXJA Forum User
- Location
- colorado springs, co
Yup mine does that too. Supposedly you could radius the IAC outlet under the throttle blade and it would help, but I never cared enough to do it.
blakews2217
NAXJA Forum User
- Location
- Alton, Illinois
I'm with him. Just roll the windows down if it's nice out or turn the radio up if it's not. It can get annoying but if the windows are down my exhaust is loud enough I don't hear it.
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old_man
NAXJA Forum User
- Location
- Loveland, Colorado
Whistling was a common problem back in the day when people would remove the restriction in the flex hose over to the airbox. The restriction was there to force a vacuum to purge the crankcase gases.
Hmmm. I still have the hose connected to the cold air intake pipe. Slightly larger size hose but same valve cover fitting. Of course the cold air pipe is much larger than the original. Easy enough to add a restriction and see if it helps though.
trippled
NAXJA Forum User
- Location
- colorado springs, co
The front fitting is an air inlet. The rear valve cover fitting is a metered orifice under manifold vacuum. Under high load where manifold vacuum is low and crankcase pressure is higher, some air flow out of the front hose would be normal and is worse as the engine ages and blowby increases. The factory fitting is in front of the air box where there should be no vacuum unless the air filter is clogged. I don't think adding a restriction in the hose will solve anything other than blowing out seals.
