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Discussion Starter #1
So ive searched a bunch about this issue but couldnt figure out the problem.

Set up is a MAP short runner tube mani, FP red BB, and a COBB ebcs running TEPHRA V3

Car boosted to target pressure (24psi) using a Perrin Pro ebcs.

Had a clutch TOB failure and pulled the trans to install a 3 puck exedy clutch

Since the install, the car wont boost over 19.5psi, which is roughly gate spring pressure.

First i tried to re-align all the IC piping and intake couplers, in addition to inspecting the vac lines.

I attempted to trigger the perrin ebcs with a 12v battery to listen for the solenoid to click, and i didnt hear anything.

I ended up buying a brand new COBB ebcs, and the issue did not solve itself. No matter what i set target boost to, the result is 19.5psi. Im not getting any excessive shaft play, or oil consumption, nor is spool latency any slower than when i was able to hit 24psi.

i cant find any cracks in the manifold, or at the turbine flange. Im running a Synapse bov/dv, which seems to be working properly. At one point i connected the hot side ic piping port, directly to the gate and still got 19.5psi.

At this point im pretty stumped. All i can think of is that something is mechanically wrong with the gate actuator or the flapper. Idk if the turbo is ok or not, however, it sounds the same as b4 the clutch job, boost latency is also the same. I would think a turbo failure would produce more symptoms, ie, slower spool, oil consumption, shaft play, etc.

i looked at the boost tables and logs from all my Tephra v1 24psi pulls, vs my v3 and new clutch logs/tables, and i cant find any differences. btw, im using cobb upper and lower ic pipes, agp ic, and moore perf. 3.5" intake, with id1000s, walbro 450, AMS dp, uego WB, and the FP red BB with a 19lb gate spring. i log with evoscan and live tuner.

Any thoughts are appreciated. I have no way of doing a boost leak test, due to a lack of a air comp, but all my clamps and couplers seem ok. The ebcs is hooked up correctly as far as i can tell, with a direct line from compressor outlet, and a direct line to the WG. no T-fittings or pills. the passive solenoid is looped and plugged in as well.

This issue is driving me nuts, and id love to know if anyone has had a similar issue. Is it common for a WG spring to weaken, or the flapper to leak when closed, without having a slower spool up, or consistent max boost level? Seems like a leaking flapper would cause slower spool, or some other decreased performance symptom.

Thanks for reading. Keep it between the ditches and keep those wrenches turning!!

I should also mention that i just discovered the lack of boost problem, and its been about 4 months and 3000mi since the clutch install, and V3 update, so the clutch, ECU mod, and ebcs are the only parts that are different btwn seeing correct target boost and not seeing it. I monitor boost via a 5v ref aem boost gauge and the oem map sensor, both of which agree with each other.
 

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Ensure you have the right lines going to the right hose barbs on the EBCS.

Also make sure you have the right solenoid plugged into the correct connector.
 

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Discussion Starter #3
So i finally figured out the problem. It was a vacuum leak as far as i can tell. i searched the engine bay too many times and found nothing. until one day i had the back seat out for some reason with the engine running. I see a random rubber hose coming through a grommet on the passenger rear seat floor. i traced it and found it wasnt connected after it passed into the cabin. i plugged it my finger and my idle smoothed way out. (id been fighting a wonky idle for months). then i saw a barb on the washer tank. i connected the hose to it and the idle remained good. i traced it under the car and saw that it went to the rear diff of all things. since then, i can hit any target boost i set. i have some thoughts on what that vac line does but i see no mention of it in the mitsubishi service manual, so who knows. all i know is it fixed all my driveability issues. i even had to re tune the injector dead times because my idle LTFTs got high after i fixed it.

i never thought to look for a vac leak under the rear seat. Who would really?
 
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