Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Longjon on May 10, 2010, 02:14:01 PM

Title: Possible vacuum leak 4.7 V8
Post by: Longjon on May 10, 2010, 02:14:01 PM

Hi,

As the title says, I have what sounds like rushing air at the base of the throttle body, the small opening with the idle control valve. It sounds like a vacuum leak, and when the ignition is turned off the rushing sound carries on for 1 to 2 more seconds. Is this normal for these engines. I have removed and cleaned the idle control valve and had a good look round but can't find anything untoward. The fuel consumption has increased a couple of MPG.

The  Jeep is a 99 4.7 V8 Grand.

Any help most appreciated.

Thanks

Jon

Title: Re: Possible vacuum leak 4.7 V8
Post by: Longjon on May 11, 2010, 01:35:43 PM

Quote from: Longjon on May 10, 2010, 02:14:01 PM

Hi,

As the title says, I have what sounds like rushing air at the base of the throttle body, the small opening with the idle control valve. It sounds like a vacuum leak, and when the ignition is turned off the rushing sound carries on for 1 to 2 more seconds. Is this normal for these engines. I have removed and cleaned the idle control valve and had a good look round but can't find anything untoward. The fuel consumption has increased a couple of MPG.

The  Jeep is a 99 4.7 V8 Grand.

Any help most appreciated.

Thanks

Right I've removed the TB and cleaned it all up, and the noise is coming from the opening for the IAC, sucking in lots os air even when the Ignition is turned off.


Jon