TOPIC: 2007 Chevrolet Avalanche with 5.3L Vortec Engine

Thanks guys.


And for the record, before they changed to "winter blend" on the fuel, I was averaging 16-17 hwy. When they switched, the mpg just went into the dumper.

I'm hoping when they switch back to "Summer blend" it will get even better.

Also, what is cool, my new next door neighbor has a 2004 Avalanche that's "feeling a little sluggish" and is interested in the Groove.

It "IS" a Groove thing...

Karl Fortner
Tacoma, Wa.
Gadgetman Tacoma

Wow! Great job Karl and everyone. It looks like another one for the books.

@Dan,

you mentioned cutting the groove at the 15 degree, were you referring to the bit angle to the throttle plate or the throttle plate position?

Karl

Ron has the bit cut at a 15 degree angle look closely at the stem behind the ball if you groove using that as your guide you`ll have better results. I THINK THATS WHERE THE ONES CUTTING THROUGH ON THE 5.3 AND 6.0 GM`S ARE HAVING TROUBLES. I`ve never went through on these. I also get at least alittle mpg on these if not alot.

Okay, that is what I went by. It was a very small break in the wall but I wasn't taking chances on a leak... and it looked better with that pocket filled anyway.

I moved the PCV over to the plenum side, used a T on the other hose on the left side.

There is one more hose up front that goes over to a valve or sensor, not sure which that I haven't touched and I haven't looked at doing the plugs yet. Picking up a few mpg but not a lot.

Figure I'll give it some time...

Thanks

Karl Fortner
Tacoma, Wa.
Gadgetman Tacoma

I re-visited this because I wasn't happy with the results to date.

Pulled the TB off and chased the groove again to make sure the cut was consistent... it is now. ( had a second little hole pop on the other side )

Also, worked the bottom edge of the throttle plate, it's shiny.

And it whistles

This was the before...




This is the after




Also, anyone know what this vacuum line is for, it goes over to a valve of some sort




Karl Fortner
Tacoma, Wa.
Gadgetman Tacoma

Hi Karl!

I believe that goes to the Evap Purge Solenoid, but without seeing the valve itself, I'm unsure. The valve probably has another line going from it and that line may have a service port on it - a green cap labeled "Service port 5psig max" or something like that. This is where you hook up a smoke machine to test for evap leaks.

Hope this helps.

By the way, don't cap this off at the intake - will set codes.

Scott Castleberg
Pellston, MI
Gadgetman Michigan

I believe the shorts will keep adjusting neg give it some time. As for the line I`m not sure but it is pulling some major vaccum when its open.

It goes to this and there is a vacuum line that comes off of it heading towards the firewall.




Thanks Scott

Karl Fortner
Tacoma, Wa.
Gadgetman Tacoma

Yep, I do believe that's the purge solenoid. I'll check my online resource to be sure.

Scott


Karl - that IS the purge solenoid valve.

A couple of better pic's





Also, could the flow be reduced without throwing a code or does it become time dependant?

Karl Fortner
Tacoma, Wa.
Gadgetman Tacoma

Another thing I found interesting, the Manifold is in two chambers, the front chamber - from the TB is shaped like a 2 Liter bottle with the opening to the second chamber narrowed down to about 50mm approx. Almost like a horizontal riser.

Karl Fortner
Tacoma, Wa.
Gadgetman TAcoma