So here is my issue, about 5 weeks ago, i noticed a huge drop in power while driving as i always do. I checked the boost gauge and it was only making 5 psi and once the change over happened it barely made 6 psi. I also noticed that there was oil coming out of the turbo inlet once i got it home and checked it out. so i bought a used set of turbos and just finished installing them today. I took the car for a test drive and still the same boost situation. Any suggestions? HELP!

 

download a vacuum line diagram and go over every inch of the turbo actuation system and test the solenoids to be sure they are functioning.

 

1. What are your mods?
2. Have you checked the boost couplers (from turbos to IC to intake) for leaks and tears? These are often hard to see without removal and inspection. This is the most likely culprit.
3. Do you still have the stock precat? They are prone to internal collapse and plugging up.

Check the stickies for turbo troubleshooting tips.

 

i would have thought he checked those things during the turbo replacement but those are also some things to consider.

 

I never assume anything. It's easy to overlook simple things - I know from experience...

 

my mods are simple, downpipe, midpipe, Racing beat cat back, Power FC, RE-Amemiya intake filter, and I just installed the greddy pulley kit and got rid of the factory air pump. On the turbo side, i checked all of the vaccuum lines and connection couplers as i was re assembling everything. My guess would be a vac leak somewhere because i also have a problem once it warms up, the engine reve from 1000 to 2000 rpms in 1 second pulses. I was thinking this has to do with the double throttle control. So i disconnected the white plug and it still does it but only when its hot. So i guess i am still ******* deep in aligators. I bought a hose kit and i will be spending some time in the cold buffalo winter re tracing all of the vacuum lines so maybe that will solve the problem. Also, could it be the wastegate actuator valve opening prematurly?

 

If you are getting only 6 psi with a full exhaust, you have a major boost leak, it's as simple as that.

 

I am not ruling out the boost leak, another possible problem may be a bad bypass valve opening prematurely as well. I have started re doing all of the vacuum lines so maybe i will find something leaking.

 

since i'm more knowledgable on FCs i am taking a stab with this one, i do believe the actuator lines have check valves on them and it would be very easy to install one backwards and cause all kinds of headaches tracing out a control problem. double check them and be sure they are facing(flowing) the correct directions and not causing a actuator to hang open or stay shut.

 

Look for this: https://www.rx7club.com/showthread.p...43#post4981043

 

More turbocharger troubleshooting...

http://www.autosportracetech.com/RX-7/rx7stuff.htm

 

I actually replaced all of the couplers, so that is not a problem.

 

Just make sure the clamps aren't pinching them. It's easy to overtighten them or the pipes to not align and pinch into a perfectly good coupler and get a leak.

Next question is check valves - do you have a Mityvac to test the function of the vacuum and pressure chambers? Are there any loose vacuum hoses under the UIM?

Dave

 

well folks, thanks for all of the good advice, i just finished the poor man's non-sequential and still only 5 psi, i checked the action of the double throttle control and that works fine. I have heard that if the secondary throttle plates don't open that it limits you to 5 psi. So that all checks out fine. I even put a turboxs manual boost controller in line with the wastegate actuator and tried cranking the boost that way, no luck. I am now on the edge of what i think is going to be a pretty harsh Buffalo winter so today being the last good day i think we will see for a while, I am putting the car away for winter. I will finish the rest of the vac lines come march or april.