TOPIC: 1999 Chevy S-10 4.3 V-6 Grooved w/ IAC Mod

I just finished Grooving a '99 Chevy S-10 4.3L V-6 throttle body. I also did an IAC mod on it.

Large bit. Epoxy backfill behind the Groove, in the IAC port, in back of the thin bore casting section. The bit did go into the epoxy, visible as a grey rectangle in one pic of the Groove. Backfill done before the Groove, and the epoxy worked like it should.

IAC mod- I used a hose wrapped in clear box tape inserted full depth in the IAC valve bore. This formed a base to the IAC air entry channel epoxy fill. Keeping the IAC valve bore free of epoxy. JB Quick, and other epoxy, won't stick to the slick side of box tape. After full cure, the hose comes right out with tape still stuck to it.

The square of epoxy seen in the TB upper bore fills in the entire IAC entry channel. Fill is done in a few steps. I use box tape w/ a slick side facing the channel as a dam to keep the JB Quick from going everywhere. Once this second fill step is cured, I pull the tape and do another fill of the top of the channel. After cure, I carve and sand the cured epoxy flush with the bore wall. This way airflow entry to the plate area is smoothed, to reduce air tumble. Then a hole is drilled straight down thru the epoxy fill to reach the IAC valve bore.

First two pics are an identical TB I did before, as "before pics". In second one the blue hose w/ box tape is just visible inserted in the IAC valve bore.

This method provides an adjustable IAC restriction (the hole can be drilled larger if needed.) Plus, the big nasty IAC entry channel is turned into a contour closely matching the rest of the upper bore wall.

On this TB, the big IAC entry channel is almost centered above the Groove. Without this IAC fill in mod, the air flowing down the bore wall will be disrupted, right above the critical Groove center.

This Groovy IAC-modded TB goes out to a very nice guy in Illinois, Steve Cosgrove.

You AND your '99 Chevy S-10 4.3 V-6 will Love this!!

Thank you, Steve!

Tracy G