TOPIC: 2007 Buick Rendezvous 3.5litre V6

Hey wes, I have that same noise but for me its a reminder that something is working. I have done my 07 MDX and 03 Denali. My my results have been good and my kids say it sounds like jet so I am cool with it.

Thanks for clicking through and following my path on this, gents.
What I think the groove does is mixes air and fuel better, causing the computer to decide less of each is needed; you get less air in the system by closing down the main air valve.

EDIT BY GADGETMAN: The Groove is explained time and again as amplifying the pressure curve created by the natural motion of the piston. Please see "How does The Gadgetman Groove WORK?" on YouTube.


I really only notice a whistle at stoplights, and I think that's because of the throttle plate being more closed than what was intended by the factory.
Sure the manifold vacuum is higher because of a more closed butterfly, but that is more a side effect than what the groove actually does. the bonus of that is the atomized fuel vapourizes more readily, and is mixed by the waveform into a more consistent air-fuel charge in the cylinder.

Anyway - the whistle...I'm leery of putting anything into my intake that might get sucked into my engine that shouldnt, and tape is one of those things. I'd be more inclined to try screen mesh - the aluminum or steel stuff that'll not dry out over time.

Thanks, I wish I could say mine sounded cool, but it just sounds like ear-piercing brake squeak; I will certainly try Ron's suggestion with the duct tape though.

I received the latest in this thread today, re: the whistle/squeal sound. This is just an idea, I don't know if Ron or anyone else ever tried this to fight the annoying whistle-at-idle sound.

Wes, the idea is Ron's concept of Throttle shaping. Ron had or has a Youtube vid on this. IT's easiest to do on the bigger V8 GM drive by wire TB's, harder on smaller V6 ones. You need an appropriate Dremel or similar cylinder-shaped tool, like the sanding drum one. I forget the exact one Ron used. Anyhow the idea is that you are carefully shaping the downstream throttle plate edge. You want to feather it down a bit, to eliminate the 90-degree edge, yet not touch or cut back the upstream edge. The area of the plate edge to re-shape, is the edge that the bit flat side goes against when cutting the Groove.

The very edge of the plate that seals the plate to the bore wall is beveled at a precise angle. This edge, MUST remain intact, or big problems can follow!

This is just an idea of mine, again I don't know if anyone has tried it to reduce the whistle at idle on GM DBW TB's

hopefully, Ron will see this and respond- so Wes, don't do anything unless Ron advises to do this. IT will require a Very steady hand to do, difficult but not impossible.

Tracy G

I’ve never thought it would be an issue applying plate shaping to the manifold side of the plate edge opposite the groove as well, but I think the key to this would be to do it after the groove is in place, or you could end up placing the groove too close to the closed position.
The thought here, I think, is to get as much air past the plate at the smallest opening as possible, so that the waveform the groove creates starts coming together as soon as possible as the butterfly opens. It might even aid in a larger waveform/vortex pattern being created/maintained at smaller throttle angles. The more air hitting the groove, the stronger the waveform.

I’ve used this twice- once on a 4.6liter f150 and once on a Nissan Titan. It seemed much more effective on the Ford. I started with the dremel’s cutter wheel because it seemed easier to round the sharp edge of the plate off faster, then I “dug in” as far as I dared with the drum grinder. It helped to run a Sharpie Marker around the edge of the plate beforehand so I could judge the evenness of the amount of metal I was removing. I’ve been tempted to pull Wendy’s TB and get deeper into it on my own, but Wendy’s is a bit of a pain to remove because the metal heater bypass tube connects to the threaded stud in the manifold that the TB is secured with. Removing the tube for access would involve topping off and burping the cooling system after reinstalling it, and on this vehicle, air bubbles are a bother to get rid of for some reason.

Then again, more air moving through a smaller opening could make the whistle worse, but it might also shift the frequency into a range higher than a human ear can detect. Regardless, when it’s right, you’ll probably be able to achieve a slightly lower idle speed which translates into better response off idle, when you put your foot in it.

In other news, since I relocated the MAP Sensor and tweaked the MAP enhancer circuit I put on a few months ago, fuel economy doesn’t seem to drop as much as it has in the past when the weather turns cooler and the intake air is denser (more MASSive - air/fuel ratios being calculated by the weight of the fuel and air catalyst). So I think Webdy’s running about as lean as possible prior to installing an EFIE on the upstream O2 sensor to further tighten up injector pulses. How can I tell? I took a longer drive yesterday for work, and the temperature gauge has only read that high in the summer- In the middle to upper range of what the owner’s manual says it should.

Hi Tracy, thanks for your reply.

My engine is tiny compared to those you've referenced. It's just a 2.4L four-cyl, 2009 toyota camry. As far as the whistle (specifically) at idle, it would happen on cold starts, not warm. However, it will always whistle "eeeeeeeee!" when the throttle position is between 4 and 7 % open, so coasting with very light throttle (naturally between 4 and 7 %) will produce a constant "eeeeeee" as well as letting out on the way to idle or on the way opening up past the 4-7%.

I appreciate your detailed description. I have no experience with the dremel or creating the groove for that matter and I hope it doesn't come down to that, so I will definitely attempt to exhaust all other simple possible solutions first and report back here...

When swapping throttle bodies, the biggest PIA I encounter is coolant squirting all over the place from the two coolant lines that connect to the TB. Do you all have any simple method to mitigate coolant spilling all over when you remove the throttle body?

Thanks again.

Could the whistle possibly be due to a tiny vacuum leak somewhere that's only becomes apparent with the grooved TB? I'm also wondering if I should just replace the intake manifold since this 2009 2.4 camry has over 360,000 miles. Who knows what kind of crud has built up on the inside over this kind of mileage that the air could be slamming into?

This car also does not have a seperate IAC valve/passage way, the idle air control happens entirely via the ECU & throttle body

By the way, here are a few photos of the throttle body:

Hi Wes. Pardon me, I'm a bit confused. Did you do the Groove and dimples in this TB? IT all looks real good to me!

To stop coolant squirting all over, I just clamp a small Vice Grip onto each hose before pulling them off the nipples on TB. Find a spot close enuf to the TB to minimize spillage, yet allow room to back the hose clamp back off the metal nipple.

Yes the hi pitch whistle at idle can be annoying. And the throttle plate shaping technique might or might not help that. BTW- thanks to Greg K for giving details on how he's done it!

Another subtle thing I learned years ago- is to lightly sand the upstream leading Groove edge. This removes any burrs and raised material there. You could try that before anything else. IT just might be, that there's a shape in the material there that acts like the reed in a clarinet or saxophone to make that sound. Looking at your pics of this TB, there are tiny up/down undulations in the Groove's leading edge- this is un-avoidable when Grooving. It's a VERY well-done looking Groove BTW!

Anyway, there is some combination of shapes between the Groove's edges and the plate edges, that's causing the whistle. I'd try to lightly break that upstream edge of the Groove w/ light sandpaper, or similar.

Tracy G

I've posted this in another thread, but here goes again.

The Whistle is an affect of The Groove that has been totally unpredictable as to when it will occur. It's due to the motion of the air over The Groove and the acceleration just like when you purse your lips.

To attempt altering this, I am recommending placing a piece of duct tape over the INPUT side, under the air duct, like so:


If the quality of the sound alters or goes away, THAT'S what we're looking for! Any change means we're getting close to the solution. Reposition the tape and try again.

PLEASE REPORT YOUR RESULTS ON THE THREAD I STARTED ON THE WHISTLE, Gentlemen as the primary. Then, feel free to post it anywhere else you like!

Ron

Wes- this is for you. I just did a little write-up on how I handle the coolant hoses on a TB. Just did one this afternoon, I included 2 pics as well. Look at the top of the Recent Topics, or in Service Bulletins. One way to do it!

Tracy G

Just curious as to what kind of fuel mileage you are getting I think I seen somewhere that you would mentioned over 50 miles per gallon?
Is that with a 3.5 liter V6 engine?

Sorry for the delay in approving you, Kyle. I've now got FIVE people (including yours truly) to handle my email, and they can't even catch up!

Enjoy your adventures here, and let's make EVERY vehicle Groovy!

Ron