stock sequential setup. second turbo does not come on line. have a boost guage and see the initial spike in boost followed by the drop, but it never rises again. had all the stock lines zip tied and replace with silicone a few years ago, just looking for a likely culprit before i pull the manifold and start searching.

 

I'm having the same problem. Check the lines to the vacuum chamber. I checked ALL my lines and found no leak... so now I'm thinking it's a missing/turned/otherwise FUBARed restrictor pill.

God, smog is just a month away for me... I'm half tempted to just go single. Two more times under the car, two more WHOLE days, I think, and then everything's coming out.

 

I've heard good things about Viton vac lines staying put, as they tend to be thicker and harder than silicone.

Of course, the zip ties also help.

 

Viton works really well - and the extra $60 in cost over silicone is noise compared with the amount of labour involved in replacing all the lines.

I'm deeply skeptical that zip ties have any effect on non barbed lines (and pretty much all FD hard vacuum lines have no barbs). I could not detect any difference when removing stock versus zip tied lines.

 

I doubt zip-ties would have much effect on vacuum lines. Pressure lines yes, vac lines....not so much. My first suspect would be the pressure lines.

 

the best way to prevent a vacuum/pressure line from coming off is to use the smallest, tightest hose you can fit on the barb. You should be struggling to even get that thing on it's so tight. Zipties are of limited usefulness. This has been confirmed by me with pressure tests on a single turbo car that sees 18psi.