So I have an ongoing issue, say if I shift out of 2nd and stomp the gas into third to getter goin, I have no boost unless I let the rpm drop down to idle then stomp it, I'm assuming the wastegate is getting sluggish, I have a spare set of twins on the way, so my questions are,

A- does my diagnosis sound legit
B- do I need to pull the twins out to fix wastegate
C- do I need to pull the engine to pull the twins
D- how much does this job suck haha 1-10


Any help is excellent

And I'm always looking for different opinions on witch spark plugs to use, stock internals stock twins, thanks again in advance

 

How much boost are you making when you do get boost? Could be something with the charge control valve and actuators possibly? I believe they stay in "non-sequential mode" until rpm drops below 4500. The wastegate actuator can be replaced from under the car but the actual wastegate is in the turbo manifold. Last time i pullled the turbos i undid the motor mounts and lifted up the motor a little to get out the turbos.

 

I seriously doubt it's the turbos itself, it's the turbo control system. There's a whole troubleshooting page on fixing these issues.

Dale

 

One way check valve.

 

I currently have a thread started:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/my-personal-sequential-boost-thread-broke-hopefully-fixed-988242/

And I have somewhat experienced this...my car would boost on primary turbo to 12-13psi, and when I would shift and stomp on it, I would get about 3-4psi. I found a bad check valve that was split in half and have since replaced 3 of the 4 check valves (thanks Dale) and now I am getting 3-4psi at all times. I am making progress though, and I am sure it is an actuator of turbo control solenoid of some sort.

Trev

 

You dont have to pull the engine or loosen motor mounts to get the turbos out. Mine cane right out the top after I took the other stuff out, intake stuff, y pipe, undid the vacuum hoses, coolant hoses and the oil lines. Its not that bad, but like whats been said I doubt its your turbos its the control sysytem.

 

I. Had a feeling it was the controll system, I replaced the check valve on the pressure chamber and 2 more from under the UIM and looked over the diagrams and it looks as if they're in correctly, time and time again the pressure chamber blows the vac lines off, I have also replaced the pair of green solenoids that bolt to the UIM, and the problem still exists, another odd occurance is my catch can has accumulated fuel, could this be due to secondary injectors spraying with no additional boost to burn fuel resulting in fuel in oil evaporating into catch can, or could this have anything to do with fouled spark plugs? Any recommendations for new plugs?

Thanks-
Jeff.

 

If you have hoses blowing off routinely, you're either using baked stock hoses or the wrong vacuum hose. I only use HoseTechniques silicone vacuum hose, 3.5mm fits most of the regular vacuum hoses.

Do you have stock check valves or aftermarket? The stock ones fail ALL the time. PM me, I sell Viton replacements at a fraction of the stock cost.

Next is your vacuum line routing, if you have vacuum hoses hooked up to the wrong places you'll have problems. Get the vacuum hose diagram and have it printed in color in 11x17 by a local print shop. I had mine printed at 11x17 and laminated for $6 at a local Kinko's, I use it ALL the time.

Catch cans always have a gas/oil vapor, that's normal. If it's pure, rank gas something really weird is going on. The secondaries will only inject the appropriate fuel for the amount of boost, that's what the ECU's job is.

Old plugs are always a possibility, if your car is modded more than stock get 4 of the NGK BUR9EQ or EQP's. They're usually available at local parts stores for a fair price.

The green solenoids you replaced are the stock boost control solenoids. That could be an issue, but it sounds like the second turbo isn't coming online, and they have nothing to do with that.

Dale