My FD recently developed an issue building boost. The car drives happily naturally aspirated and the turbos spool a little bit, but the car is only capable of boosting to atmospheric pressure and won't budge a single PSI over.

I've listened and tested for air leaks with a smoke test and soapy water on all the couplings with no luck, the car isn't making any obvious air leak noises.
I've also checked my BOV/charge relief valves for leaks and they hold pressure fine and actuate when they're supposed to.
When I let off throttle suddenly my HKS BOV will still vent but only very slightly.

Maybe there's something wrong with my wastegate/wastegate actuator?? Does anyone have ideas for other things to check?
Thanks,
Joey

 

Typically no boost means a huge boost leak. This can be as simple as a hose clamp going to the intercooler that's not tight. A visual inspection and it will look fine, but all the pressure is escaping.

Ran into that on a friend's car once - no weird noises, just non-turbo FD .

For it to be NO boost it has to be a substantial leak, not just a small vacuum hose or something.

Wastegates fail closed, so if the waste gate had some sort of problem you'd have too much boost. If the arm broke off or came off or something it would be flapping around, you'd get a metallic rattling at idle and driving around of the waste gate flapper moving.

Anyhow, I vote boost leak

Also, a smoke test may not show anything if it's a loose hose clamp or something. The smoke isn't under significant pressure, that leak is probably somewhat sealed at zero pressure.

Dale

 

As you look for those boost leaks, be sure to check the big rubber coupler that connects the top of the turbo Y pipe to the cross-over tube. They can develop a lengthwise split that opens up under boost but is nearly invisible otherwise. You may have to remove it from the car and stretch/poke at it from the inside to reveal the split.

This covers it and a lot more: FD3S:Twin Turbo Troubleshooting - Rotary Engine Wiki

 

I checked the wastegate actuator arm and the c clip had come off and left the wastegate flapping open.
I reattached the arm with a new C clip and the issue persists.. Still no boost
Haven't yet checked again to see if the new c clip also fell off since the wastegate actuator is really hot after test driving.

I've already inspected, and reinstalled all the rubber couplers besides the Y pipe coupler. Could not see any signs of a boost leak. Tried the soapy water test with the car running and also could not see any leaks out of the couplers. Where else should I check for leaks?

 

Thanks for the tip I checked that y pipe coupler but didn't take it completely out of the car to inspect the inside wall. Will pull it out to see tomorrow.

 

Secondary charge valve stuck open would do it.

 

I know this thread is old but did you end up finding out what was wrong? Having the same issue with my boost currently

 

One time I had a silcone coupler come all the way off (on one side), and the car still made a few pounds of boost somehow.
I guess it was just throwing enough air in the general direction of the intercooler to keep it above atmospheric.

He should be able to clearly hear such a massive boost leak.