My Second Turbo is not kicking in. boost shows 11-8-4.5psi. Is there a chance that secondary turbo is not blown? Also there is a strange sound only at around 2500-3000rpm. It goes like BRAAAW. i found the tube is open i dont know what tube is this, the sound comes from around that area, not not sure though. I'm uploading the video on youtube and will post it as soon as available.

 

Your turbo is not blown, you simply have a sequential control issue. Just search on the forum there is a ton of info but it is really hard for us to diagnose over the computer.

 

Charge relief solenoid (pretty easy to get to)
Charge relief valve or "CRV"
Boost leak from rear half of Y-pipe

Could be lots of things, but that's where I'd start.

http://www.fighters-garage.com/rx7.html
Scroll all the way down to the bottom, that thing is a life saver.

 

I don't believe the sound has anything to do with your boost issue. Check this thread on the sound:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/eliminate-air-pump-moo-%241-1-minute-486061/

As for your boost issue, I would start with checking the check valves for the turbo control system. Make sure you don't have a mis-routing issue with the vacuum lines as well.

 

Here is the video of i took today the sound comes only at certain, very nerrow rpm range and the dissapears again: http://www.youtube.com/watch?v=8MECu98alOw

 

Search the user name DaleClark. He posted a very simple fix for hte "moo cow" noise for the air pump piping.

 

is it dangerous that this pipe is open?

 

today i checked that primary turbo is not generating full boost always. sometimes it goes and sometimes it does not

 

Its not dangerous it just makes the annoying noise you hear.

 

https://www.rx7club.com/showpost.php...34&postcount=8

 

ok this thred turns into official help beqa with his car thread. i noticed that when warm but still not at fully operating temperature i rize revs a little and let them fall beck, the engine stumbles a little for 2-3 seconds and then goes back to normal idle again. this doesnt happen when engine is fully warmed up

also, we tested boost again with another gauge and it showed 7psi and then started to go down at very high RPMs it stayd at 4psi

 

i was looking at this diagram, found charge relief valve but didnt find charge relief solenoid. where is it? where on diagram can i find it?

 

The solenoid is on the rack:

http://www.fd3s.net/vacuum_hose_replacement.html

 

Car is probably just running rich while warming up and your plugs are fouled a bit.

You'll have to start checking vacuum hoses, solenoids and check valves. Good luck, the seq system can be a nightmare for a first timer.

 

Check the hose off the y-pipe that leads to the charge relief valve. It is the 3/4ths inch hose just below the 3" hose in your picture. You can also see the top of the charge relief valve in the picture (right at the bottom edge). The hose I mentioned is known to split or crack at the bend.

 

I checked it. it's fine. i found today that pressure hose that goes to the blow off valve was cracked. you can see it on the picture


I replaced it with another hose. Also i found that fose on primary turbo inlet was lose and tghtened it. didnt have a chance to look under the car at turbo control actuator but with KOKO test i saw charge control actuator work. Now primary spools up realy fast to 10psi but then boost again falls down gradualy to around 4 psi. I will check turbo control actuator tomorrow, what else should i check?

 

Then it is probably either the charge relief valve or the charge relief solenoid (in the rack) that is not operating properly. You are blowing boost out of the y-pipe so if the hoses are all intact and the charge control valve is working, then it comes down to the charge relief function. It mus be hanging open. Be sure also that the y-pipe is bolted up tight to the turbo output ports.

 

getgone
I will test charge relief valve today with pressure and boost gauge, we fabricated custom, very funny device for this

Maybe i'm missing something but i didnt find charge relief solenoid on your link only charge relief valve.

 

So i decided to open new topic, my previous topic is here: https://www.rx7club.com/showthread.php?t=723333

After finding and replacing cracked hose leading to blow off valve, my first turbo boost improved. its boosting 10psi and then gradualy falls down to 4. I'm measuring boost from intake manifold.

Today I checked double throttle actuator and i found that there is no vacum in that hose . We removed intake manifold an saw that that hose was going into a pipe and the other side of that pipe was leading nowhere also there is one empty pipe there
see the pic below:



On vacuum diagram i checked that it must lead to second vacuum chamber but i couldnot find this second chamber. do you guys have pictures by which i can find this chamber?
follow green wire coming from double throttle actuator below:

 

Oh the small one, I think that is only on automatics.

 

since you've already got the uim off why not upgrade to the simplified vaccum line setup?

 

blwnrtr93
links pelase?

my secondary still not kicking in i dont think double throttle will affect this

 

Look at the legend on the vacuum diagrams for solenoid "H".

 

DT would cause lower boost at all RPMs. Worse on the high end, but you would prob notice some loss on the low end as well.

 

By how much can it lower the boost? I'm getting a bit over 4psi on high end