LT5 Vacumn Routing

The vacumn routing in the 1991 manual is not clear as to the correct routing of of secondary vacumn and 1/4 inch pipes specifically to the purge solinoid under the plenum (this car has the purge cannister at the rear).Does a clear drawing exist for the 1991 engine with purge solinoid under the plenum.The drawing on zr1.net is also for a 1990 with purge cannister left front

[Rob]

Chris,

I'm not sure if this will be helpful or not, but check out my article here: http://corvetteactioncenter.com/foru...threadid=14272

Great article Rob.This is the real problem.A non Zr1 person had previously worked on this car and many a system had been played with .My task is to bring this car back to standard with the help of a manual and form informative articles like your own.I have no secondaries openining and no vacumn on the cruise control system.My objective is to replace parts were necessary as per your article and to get the system working.The secondary vacumn pipes have been replaced with part number 10146221 and o rings and injectors have been ultrasonically cleaned and flow tested. Does any body now why the 93-95 has a differant part number 10168824 and is this because the purge solinoid on the later models is under the plenum and therfore has differant routing?

[Rob]

Hmmmm....interesting....I was under the impression that the secondary port vacuum system was the same for both generations of LT5. I didn't realize there were different part numbers.

As far as diagnosing secondary port vacuum problems, I can't stress enough how important it is to have a hand held vacuum pump like the one I show in my article. That little bugger has saved me a lot of time and hassles.