Im not to familiar with my car yet. I bought the car after it had sat for a few years. The motor had a fresh rebuild by rotary performance about 5000 miles ago. I replaced all the vacuum lines and double checked. The car has 102,000 miles on the turbos.

Heres my issue. The turbos are always spinning but they're not always building boost. Sometimes I will get on it and i wont build boost, then when i get off there's a funny sound coming from the motor. Then ill shift a gear and the car feels fantastic and holds 10psi until i get off and there's no funny sound. The boost isn't consistent enough. One gear will have boost then the next has nothing. If i role into the throttle it seems to build boost. Its weird and i just need some opinions.

My friends have told me it sounds like my turbo manifold is cracked and its a known issue. Rotary Performance said my turbos looked great, so...idk.

 

the sound is like..? mods on the car? more details

 

the sound is likely the wastegate dumping exhaust. the issue usually arises after the sequential system tries to activate at around 4000-4500RPMs then you switch gears and the secondary hangs open and dumps all the boost indefinitely. there is no pinpoint cause for what causes it as it can be one of many things, but usually the culprit is faulty control solenoids on the UIM for transition and wastegate controls.

you can also make a boost leak tester from couplers at home depot and a tire valve stem. ruling out leaks in the intake tract will help keep boost levels more consistent, if the stock system can't reliably get up to 10PSI then the sequential system will not work properly regardless if the electronics and lines are all perfectly fine.

 

i had a similar issue.

my problem ended up being the Charge Control Actuator in the Y-pipe getting stuck closed.

bought a used y-pipe with a known good CCA and all is well.

 

Start with the basics. Boost leaks can cause these symptoms and they're easy to solve.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/boost-issue-not-going-over-7-psi-716185/

 

good luck! at least its boost and not seals!