madhat1111

I've been having symptoms of a sticky TCV...boost falls to zero at high rpms, car is sluggish after a mid to higher rpm shift. I've gone through and checked vacuum/boost using @DaleClark sequential trouble shooting guide, and I *think* it might be the TCV that's sticking. Everything seemed to show boost/vacuum as Dale described, though the charge relief valve didn't have any air noise when disconnecting (not that he said it would). I've done @Speed of light "easy fix" adding in the extra check valve. I haven't taken the TCV itself out to test, but I think I need to confirm before I just replace it.
Contacted Ray, who of course said NLA...what's the solution at this point? Do I get a used 25 year old valve and hope it lasts? Has the aftermarket come up with another solution, other than going single turbo?

(Stock 94 JDM car, equivalent to 14k miles, other than Tanabe exhaust and Profec boost controller.)

DaleClark

iTrader: (55)

Is this something that it just started doing or it has done since you got the car? Have you done any work on the car between when it was working right and now?

Typically a sticking turbo control valve will transition to twin turbo and will then stay open. So you run it up in, say, 1st gear, then shift to 2nd or 3rd, and at low RPM the car is sluggish since that door is still open.

Teeing your boost gauge into things is the next step. That will let you find out exactly which component is not cooperating.

Dale

madhat1111

It's post me getting, but before I had a boost gauge. It is definitely more sluggish than it used to be. I replaced the turbo control solenoid already, and thought that fixed it, but it might have been a placebo and I just didn't really run it through its paces.
I've gone through with my boost gauge and tried all the ports you mentioned in your guide, and they all seem to be working as they should. Maybe I should record my boost/tach and test at each location again in case I just missed something acting screwy that yall might recognize.
What you say is a symptom of a sticky valve is exactly what I'm feeling...sluggish/low boost after a shift to lower rpm.

DaleClark

iTrader: (55)

This is the valve that many have problems with -

https://www.atkinsrotary.com/store/9...A1-18-741.html

That link also has the part number, it looks to be in stock no problems. You may want to tee into it and observe its behavior first.

Also is the car in good shape besides - fresh spark plugs, etc?

Dale

madhat1111

I replaced that solenoid (sourced from Ray) this spring. I'll tee in again and make sure they're closing (I remember them doing it, but I'll video it)

It's in very good shape otherwise - idles perfectly and has plenty of oomph when the turbos are actuating correctly.