Ok..this issue is, if I do a 1, 2, 3 and ride out 3rd, and then just cruise, I get no boost, just goes to 0, below 5500 rpm. Once I get past the transion I get boost, 10psi. If I KOKO, its just fine. Or if I drive for a bit it sooner or later goes back to normal.

What would be causing this? Something in the Y-Pipe? Oh I have done the sequencial simplification. I did see a "butterfly" (whatever they are called) in the y-pipe, could that be it. Solonoid not opening/closeing it? Where should I start?

Thanks,
Jeff

 

I'm not exactly sure what you mean here...full throttle?
Are you getting normal boost except in 3rd gear?

 

You might want to check your turbo control solenoid, the one on the ACV, but your description is pretty unclear.

 

I had the same problem and I have since gone to the non-sequential. My TCA was very difficult to move once I removed it so I think it was about to freeze up.

 

Sounds like he is getting secondary with no primary. That can't be possible ... can it?

 

Technovice: No it's said that the primary needs to make 7 psi before it's possible to get any boost on the secondary. So technically it shouldn't be possible.

By sequential simplification, you mean "non-sequential" or "poor mans non-sequential" right? Did you remove the TCA, and wire the door open?


Was this a problem before the sequential simplification and what is KOKO?

 

Wastegate issue?

 

OK..sorry. Just got back home.

1, 2, 3 WOT. Then If i just shift to 4th and criuse I have no boost under 5500, or in any gear. Now if I downshift and bring it back above 5500 I have full boost. Also its the same if I just keep it in 4th, no boost till after the transistion would be.

Its not a 'whooshing' sound under the hood. More like something is closed and perssure is forcing its way out. Dunno how to explaine the sound...

And heres the kicker. Is sparatic. Sometimes it does it others it doesnt. More times then not I can plan on it happening as to not pull out into traffic. Im a little stumped.

Oh and by simplification I mean the one on robs site. Im still sequential. http://www.rx7turboturbo.com/robrobi...lification.htm Has a vac hose map.

KOKO - Key on key off.
In this case I turned the car off then back on. Everything is fine then.

 

Did you check for leaks in your couplers etc? I know this sounds weird but if it's a small leak, sometimes you'll still get boost on the secondary turbo because you're simply pushing too much air through with that 2nd turbo to have all of it leak out.

Other than that, I am at a loss for what it could be. Have no idea what would do that and still be sparatic.

 

Any other mods?

I think I'd look and look again for a boost leak. I can't see how this would occur otherwise.

Have you been rerouting hoses?

I wonder if it is possible to leak all primary boost through a malfunctioning pre-control valve.

 

Well I dont see how a leak could do it. If I do a quick 1, 2 at WOT, 9times outta 10 I wont have the prob, and I get full boost through out. 3rd seems to be that magical gear. After I strech out its legs in 3rd, 8 times outta 10 I will have the boost prob. Man its annoing.

Well Ill start looking for leaks anyway.

Any other ideas or have I stumped the rotor gods?

 

You need to do a 40-70 run in 3rd gear. Cruise steady at 35 mph in 3rd . Floor it and have someone watch the boost and note the boost pattern. Be as thorough and specific as possible. If you get instant 10 psi @ 4500 rpms, I need to know. If it is slow to build, I need to know. Your information is still very vague. We can help you, but very precise information is required.

You should get:
rpm psi
3,000 10
4,500 8 (as 2d turbo comes on)
4,500+ 10 (recovers almost immediately)
6,000+ 8 (and holds to redline)

Let me know what your numbers are.

Have you checked the usual boost leak culprits?
Y-pipe
Y-pipe coupling
1" diameter hoses
Primary Turbo Inlet
Couplers To/From Intercooler

You may have multiple issues.

1. Give a FULL report on your boost behavior based on the "chart" above. How it builds, drops... everything.

 

Searching for something else I noticed I left a problem unanswered. I hate those threads. So resurrecting to close it for future reference.

My boost pattern was:

RPM - PSI

Run 1
3,000 - 12
4,500 - 10
4,500+ - 12
6,000+ - 12

Run 2 - Right after run 1. Condition would remain untill car sat for ~20 min.
3,000 - 0
4,500 - 0
4,500 - 12
6,000 - 12

Problem was in fact the solenoid that controlled the TCA (Turbo Control Actuator). The TCA would remain out. Pressure would be built up by the first run to actuate the TCA, but the solenoid would never release it so it would be stuck.

Replaced the solinoid on the wiring harness and everything worked fine.

Thanks to those who helped.