Hey folks. I searched all over the forums and even on google but didn't find anything that resembled my issue.
Have a 2001 Jeep Grand Cherokee Limited. V8. 150K
Runs great. no issues to speak off.
When I floor it and accelerate hard, when it shifts, there is a faint sound that sounds like a super charger blowoff valve. Im not talking about a vent to atmosphere aftermarket type. Im talking about something that would sound stock on say an F150 Lightning. I say this for reference because I used to own an F150 Harley Davidson with a stock Supercharger and it really sounds the same to me when I hear the "blowoff" sound.
Does it in 1-2 and 2-3. Never kept my foot in it long enough to see if it does it again.
This truck is stock, so no supercharger.
Doesn't seem like its doing any harm, but it cant be good.
Anyone know what this might be? Is this normal on these vehicles?

 

I had a buddy with a 5.0 foxbody mustang that had something like this. It was coming from his intake manifold and it sounded like a tea kettle. Not sure if you have something similar.

I'd start by checking your whole intake system and check for leaks/cracks.

To be clear, does the sound occur when you let off the gas or when you get on it?

 

The sound happens right during the shift with the throttle all the way down.

 

Belt squeal? When upshifting the engine RPM suddenly drops and the accessories want to keep spinning at higher RPM causing the belt to squeal or chirp. This would mainly happen at higher RPM, heavy throttle shifts. I've seen alternator applications that actually had a one-way clutch to prevent this.

 

one of the bolts on the back of the manifold may have backed its wa y out just a bit allowing a small amount of air to get sucked in. it does sound like forced induction. might be worth a check.

 

This sounds more like the sound. Ill have to dig around back there and see if I can tell. I'll try shooting some starter fluid around the back to see if theres a leak.

It does sound like forced air. Like a "phisss-hsssssss". Lol. Comic books. Definitely not a belt squeal sound.

 

haha, i didnt fix mine right away cause it doesnt impact performance and i love the sound of turbos.. but yeah, people give a second glance sometimes, pretty funny..

 

Let us know if that's where the problem is.