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-   -   Still no boost after all this? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/still-no-boost-after-all-37224/)

7-sins 12-06-01 04:36 PM

Still no boost after all this?
 
I was out testing my car tonight and the boost is always 10-5-2 :rant: it just kinda slowly drops the higher the rpms. I just installed a downpipe and midpipe thinking it was a clogged cat. I also did a hose job while my car was down. Still no boost. I know all the hoses are in the right spots and all the "C" clips are on the actuators. What do you guys think, could I have a bum secondary?

DavidZ 12-06-01 05:24 PM

I think i have a similar problem, but my boost pattern is 10-5-5. I also just put in a downpipe and midpipe, with no improvement.

I'm thinking it is now something to do with my turbo control actuator. The pressure side of the actuator is not holding pressure that well.

Have you tested your TCA?
Have you teed a line into the crv to check if the 2nd turbo is prespooling?

I'll keep you posted if i solve it. E-mail me if yoiu have any testing questions.

Dave

hapa 12-06-01 05:27 PM

7sins, I would check your solenoids, I think one of them is lazy and doesn't open completely. I'd get a hand pump and test them individually. Most turbo failures are primaries, not secondaries, and since your getting good boost on the primary and your boost is falling off, my guess would be a solenoid or actuator.

eric

Mach2 12-06-01 05:40 PM

I highly doubt that your secondary turbo is bad. It sounds like you have a problem with the turbo control system(solenoids, actuators, check valves, etc.). It's very hard to diagnose these kinds of problems without actually seeing the car. I had a problem with the boost on my secondary, but I wasn't getting "any" boost (0psi) after the transition. Ending up being the two hoses that lead to the turbo control solenoid attached to the ACV on the LIM had been reversed. Be patient and you'll eventually figure it out. Good Luck!

7-sins 12-06-01 08:07 PM

Thanks for all the responses guys!! :bigthumb:

I dont think it is pre-spooling but.... I have tested the Turbo precontrol & Wastegate control solenoids. They tested out fine, I also checked the actuators and they moved with the hand pump. The lines are all in place and the pills are in the lines. How many other solenoids under the manifold have to deal with the secondary? I know the Charge control & relief would but most of the others are like EGR, Switching, Double Throttle control, ect. Maybe it's pre-spooling but the Charge control valve doesnt open.

Do think think it would be wise to do a "poor man" non-sequential set up just to test? It looked pretty easy to do and is reversible.

DavidZ-
Which line is the one I would want to tee into. The one closest to the firewall?

DavidZ 12-06-01 09:20 PM

Yeah, i'm not getting any prespool. I've got to check some more solenoids later. But anyway heres where i teed into. It is right behind the where the CRV comes off the lower portion of the y-pipe. See the pic. Anyway, i off of this line, i get 0 psi until about 4000 rpms then it goes straight to 5 psi, same as what it shows on my boost gauge.

Normally it should start seeing pressure at 3000-3500 then it should climb to about 8-10 psi by 4500.

good luck, let me know if you solve it. Dave

7-sins 12-07-01 12:31 AM

Ok, after looking over all the diagrams it has to be either the TCA gone bad or either of the solenoids which control it. I'm not up to pulling off the upper intake manifold again because I have done too much to it over the past two weeks and im burnt out. I really do think Dave you might have the same problems. If you look at this diagram..... http://home.istar.ca/~dvandit/Second...rolDiagram.htm you can see that the valve that lets most of the exhaust to the secondary turbo, is the TCA. The precontrol valve is just a smaller valve to prevent boost lag. Now if the majority of the exhaust was being held back by the TCA's valve then you would only see a small amount of boost because the small amount of exhaust flow through that precontrol valve.

Since I would rather not pull off the upper intake manifold again leaving my car down, I am questioning just to do the "poor man" non-sequential setup for a little. Maybe when it starts to snow, since I wont be driving my car, I will pull off the intake manifold for some more work. I am going to make a new thread asking people about their thoughts on non-sequential.

Once again thanks for your guys help,
Chris


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