Grant01

Besides my idle issue, One thing I have realized is the turbos spool precise one time. Basically as soon as you start the car after it sits for about 10 to 15 minutes it will spool the turbos completely normally, once you finally let off it will only build low pressure at best and it sounds like I'm running with a boost coupler off when you go full throttle. I have checked for vacuum leaks with a smoke tester and was unable to find a leak. What is the next step to start with. It seems like boost release is controlled by multiple sensors.

Project88Turbo

iTrader: (22)

I had a similar issue with my car when I first got it, it would make full boost sometimes, then you'd shift gears and it would be gone. And there was a really odd "whooo" sound when it happened.

Fritz Flynn directed me to check the big silver actuator at the front of the turbo manifold with two hoses attached. It would hold pressure or vacuum on one side, but the other leaked badly. The one he provided me fixed the issue.

Good luck!
Vince

moehler

iTrader: (12)

See if this describes your issue -

https://www.rx7club.com/3rd-generati...ctive-1120259/

Grant01

Are you referring to the wastegate actuator on the bottom of the turbos?

I already smoked checked the car, did yours leak to the external

Did you replace it?

Grant01

This sounds very similar to what I'm experiencing. If I am at highway speeds it still feels like I build boost but it just can't build enough to feel quick. When thetsequential turbos work right after first starting it up they bang on so hard, but once it's over you still feel it build boost it just doesn't work very well. I will buy some parts and give this a try tomorrow. Nice easy cheap *** to try if nothing else

KompressorLOgic

iTrader: (6)

one time I used a purge control 2way valve instead of a turbo control 3 way valve and it did something like that.

Project88Turbo

iTrader: (22)

I'm not talking about the 2 wastegate type things, but the much larger one that is lower attached to the manifold. If I'm not mistaken, it is the TCA they are referring to in the link above.

I never smoke checked it so I can't say if it leaked externally, but it probably would have if the smoke was applied directly to it. You could hear it leaking from one side.

The only easy way to see it is to get under the car with the under tray off, and it is right there under the turbos with a little heat shield on it. Then I tested it with a Mighty Vac. You will see the actuator move one way or the other depending on pressure or vacuum, then try the other hose hooked to it.

Post describing the TCA and how it works.

I'd start looking at the TCA, when more than one person gone up with the same answer here it's usually the right one.

Vince

Grant01

I completed the a solenoid bypass as recommended in the do-it-yourself above. Now I do not even get a single spool of the secondary. The primary seems like it still works but secondary does little to nothing all the time.

I also inspected the vacuum lines on the TCA and it is in good condition

nickmc07

iTrader: (1)

Have you tested the solenoids that control the sequential system?
great write up here
https://www.rx7club.com/3rd-generati...o-stuff-802060

Grant01

I have not.... Sounds more fun to ram my head into an ice pick than test the bastards since removing them is the shitties job ever

Project88Turbo

iTrader: (22)

Did you apply boost or vacuum to the TCA? That's the only way to test it.

Vince

Grant01

I plan to tomorrow. I also intend to check the vacuum lines feeding the charge relief valve and actuator. I found a couple videos/posts showing the tca still actuating, but not boosting due to a crossed line to the valve. And best I can tell this valve is only for the secondary turbo.

I just replaced the engine and all the rats nest hoses, so getting a line crossed is possible.

Project88Turbo

iTrader: (22)

It took me about a week to fully reassemble my engine, with the vacuum lines taking almost a whole day. It is a lot going on under the plenum. Don't give up though, it's worth it to feel them working properly!

Vince

nickmc07

iTrader: (1)

​​​​​ Thats a pretty accurate statement.
A lot going on under there you'd be surprised what you uncover.
Good luck

Grant01

I have validated all of the lines and found I had double throttle and vacuum chamber switched as they entered and to the upper intake manifold. I also had the check without going into the vacuum chamber backwards.... Time to button this all back up and see if that was the culprit.

I did also validate the TCA does work under pressure using my air compressor and a line as it enters directly behind the vacuum pump. It fully and completely actuated with smooth operation

Grant01

The source of my problem what's the incorrectly flowing vacuum chamber hose and check valve. Now I have consistent and strong boost everywhere I should. Thanks for the help everyone. Hopefully this post help somebody else along the way