joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
Me thinks a vacuum line along the firewall/battery area?
The pitch can be varied with very slight changes in the throttle. It is very loud but will go away when the vehicle warms up.
Additional thoughts?
Rather than hose it all down with starting fluid I prefer an unlit propane torch, less mess, same results.
After you clean the throttle body and replace the TB gasket, if the noise is still there try putting a little wheel bearing grease on the ends of the throttle plate shaft where it exits the TB--a slight leak in that area can cause a high pitch noise.
FYI--last year for the EGR--Exhaust Gas Recirculation--on the 4.0 was 1990. On the valve cover is the CCV--Crank Case Ventilation--like a PCV system only with a metered orifice rather than a valve. The front grommet on the VC is the filtered fresh air intake. The rear has the metered orifice and is connected to the vacuum port on the intake manifold.
Searching through youtube, I found a 2003 WJ that has the EXACT same whistle, http://www.youtube.com/watch?v=Y5_m6LRqkAw I hope that the original poster checks in to see if their whistle is the same as this.