Well with all of your help and suggestions I replaced my intake manifold gasket and got the car running with a smooth and stable idle, its really nice and I'm pretty pleased with it. a 1/2 turn from
But the RX-7 gods givith and takith away and now my car that had a reliable 10-8-10 boost pattern has a 10-5-5 boost pattern, It falls off after 4500rpm and never recovers full boost. I'm pretty bummed after all of that work and am a meticulous re-assembler so the most logical thing is something I did but Im having trouble seeing anything wrong in my work.

I removed the turbos and the intake manifold, but left the rats nest alone. I never removed the turbo wastegate or turbo precontrol actuators from the assembly so only moved off the hoses needed to move the turbo assembly out of the car. The turbo control actuator I did remove, and replaced the retention clip when putting it back together.

Here's what I know, I tried to follow the diagnostic notes for the issue

• Little turbo works great, I have full boost down low
• My little turbo makes 4psi+ on WOT without load
• My double throttle actuator stops drawing vacuum when the engine is up to temp
• I have 17 inches vacuum
• My Pressure tank holds pressure
• My Vacuum system does NOT hold vacuum.
• The tank itself holds vacuum, hooking up to the rats nest it does not hold any vacuum on my mighty vac gun
• My check valve for the vacuum side is great, holds 25 inches for a really long time
• My Turbo Actuator Control is really really hard to pull on with the lines attached, but it does move.

So... Im guessing I have a leak somewhere in the vacuum side of that system, whats the best way to diagnose? Do I pump smoke into the vacuum tube on the nest and look for it? Key on Key off check?
Should I check the TAC? Am I going the right way? Good next step idea?

I would love for this thing to run right finally (-=

 

First off, you are saying "little turbo" - there's a myth that goes around that the FD has 2 different sized turbos. It doesn't. They are both identical. You can refer to them as primary turbo and secondary turbo.

That said, it does sound like your vacuum system is at fault. If you have no vacuum going to the TCA for transition it's not going to work right.

Could be the solenoid is sticking or you have a small tear in one of the vacuum lines. I would start with that.

Also make sure the 2 lines to the turbo control actuator aren't swapped. If you have the OEM lines to it they are pretty hard to mix up but if you have aftermarket lines it's possible.

Dale

 

If the hoses to the actuators aren't swapped, is it possible that the wastegate and precontrol solenoid connectors got reversed?

 

The fact you're getting 10psi sounds like wastgate/precontrol are OK. Big thing here is the system not holding vacuum. No vacuum = no turbo control door opening = no boost worth talking about after 4500 rpm.

Dale

 

small, front, Primary , large, back, Secondary. Fixed it! (-=

I can definitely make 10 psi on the Primary so that's a good check, I was worried about that a little as well. So ill blow smoke in the vacuum side and see what i can find after a try to switch the TCA lines, They are still stock so I dont think that would have been an easy mistake, but its an easy test

If i do have a sticking solenoid am i thinking correctly that I would check the turbo control solenoid first? or is it the "E" turbo control solenoid together with the turbo control solenoid that controls it ?

 

My guess is a vacuum /boost leak between the secondary turbo and the charge control valve. The charge control valve is closed low RPM when only the primary turbo is operating, so a leak there would only affect manifold pressure at high RPM when both turbos are supposed to be operating.

 

The E solenoid is TCA pressure. The turbo control solenoid that sits above the rats nest is the one that controls the vacuum and connects to the vac tank. There is also the charge relief solenoid H connected to the vac tank.

 

So what i did was....

Thanks all for the help, I think I've got her sorted now.

Got the most helpful girlfriend to acquire more cheap cigars and we smoked the vacuum circuit with a T between the VAC reservoir and the check valve so we could look for leaks in the whole thing and double check my previous troubleshooting, pulled the nipple off of the Upper intake manifold extension so if the check valve leaked we would see it in the intake track.
Started smoking and after lots of looking we were able to see smoking coming out of the airbox? So i pulled off the airbox, and airpump, then started pulling off the extensions to the turbo inlets and... Smoke was coming out of the turbos, on the intake side.
After a lot of looking at the color coded vacuum diagram and struggling to find how in the hell the vacuum system was connected to my turbos now, I found the error I made in hooking stuff back up, switched two lines on the back of the charge control actuator. This was leaving the vacuum system open to atmosphere/Turbo manifold pressure at idle since it should have been hooked up to the charge relief valve and I guess that means it had boost hooked up the rest of the time.
I didnt understand the series of 4 lines running to the LIM were pass thru and not some weird common manifold draw, So I needed that leap to get it and I hadn't thought about it before.
Car now feels right on the butt dyno and can hold a 10-5-8, I don't have a nice strait near home to give it a good go so its probably just my lack of WOT but its never felt faster so i am quite happy.



theres your problem right there,

in living color, the green needs to go where the yellow is currently connected.

 

Nice. I've seen a lot of cars that have those lines hooked up wrong, you do have to study the diagram to make sure you are on the right nipples for each thing. And you are correct, those nipples just pass through the intake manifold, they do not plumb into the lower intake manifold.

Dale