TOPIC: 2007 Buick Rendezvous 3.5litre V6

Greg, if you want to post or repost pics of this TB, I'll have a look. Mainly it's the basics: it's a DBW TB, look for the dark stain denoting hot engine idle throttle position. Use your Panavice to find comfortable work angles, and don't be afraid to re-position the TB in the vice several times. I find best control is when I am cutting left-to right in as close to a level position as can be.

Several years ago Karl Fortner in Wash. state was doing his DBW Chevy truck TB, and a tip he gave for DBW was to use modeling clay to hold the plate in position. I've tried it, it works, just stick a gob of modeling clay on upstream side, opposite side to the Groove location. Clay holds plate against the motor tension, frees up both hands. Set plate at or slightly open from the dark stain edge. If stain's not there, Ron's business card between plate and wall trick is the fallback. Caveat from my experience is you want the Groove located so the plate starts to cross upstream edge at a greater throttle angle than idle. Too "early" in throttle angle degrees can cause excess idle RPM's, or a truck that hot idles at 20 MPH!

Check bit/tool angles before cutting, I will mark center of axle shaft w/ sharpie pen to give aimpont to line bit shaft up to, and bit taper parallel to bore wall. So you check left/right axis alignment (tool shaft to centerpoint)and up/down axis is bit taper parallel to bore wall. I like to spend time w/ the Panavice to find a comfortable position. Begin at left side about a bit cutter-width in from bore wall, set the angles, place spinning bit flat side against plate and cut straight down, 'till shaft taper touches bore wall. Avoid "penciling" keep steady. Dipping in light oil, or water, even spraying with WD-40 between each cut or two keeps it cool! Go a half-bit cutter width to the right, repeat, I try hard to watch bit axis alignments in both planes constantly. Center of the bore/plate radius is most critical area. I find it seems to go faster as I go, I have to make myself stop, brush out the shavings w/ a toothbrush, and keep from getting carried away, it's easy to do!

I never get a "perfect" Groove despite my best efforts. Funny thing is, some of my worst-looking ones have performed the best- go figure. But a "tight" Groove where it will hold or close to hold a loose bit in it, full depth so the taper is touching the wall, all along it is ideal.

After Mike Holler's inputs several years back, I took to lightly smoothing the leading edge of the Groove (upstream side) w/ fine sandpaper to remove slightly the rough edge, the downstream edge I leave rough.

Throttle plate shaping is an option, but only AFTER the Groove is done.

hope that helps!

Tracy G

Ah, you were reading my mind about shaping the plate, and the right time to do it. Just so I don't mess with the edge that seats, I'm going to run my sharpie around the edge so that as long as I can still see black, I should be safe.

I don't have clay, so it's the business card trick for me. I'll have a better picture in my head about placement/distance from idle position once I get the TB off: I was called out unexpectedly this morning, and now the truck is cooling off while I grab a quick lunch. With luck, the rainclouds that are threatening will decide to be my friends...

Pics will come...I'll take them as I go...I really hope I don't need too much JB kwik!

Alrighty, here I go:

Battery first



Remove the PCV re route and upstream intake tube.

Intake tube. I hope that dribble of oil is just what was in the breather line before I did the PCV re route.




Inside the MAF




Time for a new one of these:

First stumbling block:
It seems I may have to remove the heater bypass tube to remove the TB:






I think I can just loosen the bolt below the bleeder valve to get myself the wiggle room I need.

Hi Greg, try a short piece of vinyl clear hose to the breather hose nipple on the air duct, to watch for gook coming thru that hose. Use Mass airflow cleaner spray on the MAF, just spray off don't touch anything in it.

I hope the dark stain is in the TB, it's your guide for Groove placement. Hobby and craft stores have the clay, it will free hands. The throttle plate will want to go to the at rest position, without clay you have to hold in place with fingers, much harder that way. Ron could do it, but I dislike that way. I'll keep my phone on if you need to call me.

Tracy G

Success!! It just took a bit of elbow grease and some gentle persuasion.




Also, it does have the line, so I know where to park the plate before I cut. So, off to get some JBKWIK, clay and a new filter.

The TB is thin, maybe 3mm, 1/8", so I'm going to build up with Kwik BEFORE I cut the groove.

Also, MAF is now clean:

Yahwhol, Herr Doktor! All ist Gud zo farr!

I'll check in here from time to time, and the phone is on. The large bit may break thru a bit, but you will have no trouble once you have built it up. Do remember to check it w/ a flashlight inside and out, and check bit fit. If you like, you can highlight the Grove's outline w/ a black Sharpie it photographs better.

I really take time when shaping a throttle plate, gotta preserve the edge seal!

Tracy G

So I've cleaned and replaced the MAF, dropped in a new filter element and built up the outside of the TB with permatex cold weld - they were out of jb kwik.





I may have laid it on a bit thick, but I don't want to have to chase down any pinholes. Also, I jammed some clay into the back of the TB to hold it in place...the pic may not show that I have the edge of the plate just at where the black carbon starts.





Clay:





Now, I don't think I'm going to be able to do a full 160 degree groove because of the housing of the DBW mechanicals...one of these pics should show the area of my concern on the left. Seeing as not much happens at the ends of the groove other than at full throttle, I'm sure it won't be a concern. Also, I'm going to start on the right and go left, like I'm writing in Arabic.

Also, while I'm posting pics, I REALLY like this stuff to clean gunk off stuff:




And for bit cooling:




And that's the last product endorsing I'll do here.

Greg, put the throttle blade at the furthest down-stream edge of the black stain, maybe a tiny bit past that. You have to strike a balance between good off-idle performance, and cutting the Groove too "early" in the blades rotation arc. I 'm unsure about cutting right to left, have you practiced that?

Tracy G

I'm about to wrestle it back on.
How do you think it looks?