RaceReadyRX7

My first turbo does not boost all the time. The second turbo is working just fine.
Sometimes I get full boost 10psi when I step on it and sometimes I only about 2psi when I step on it. When I let off the throttle after a low boost I hear a strange unwinding type sound. Without pulling the turbos is any way tell if they’re toast? Or do I possibly have another problem wastegate or vacuum? I have 79,000 miles on the car.
Thanks in advance for any and all help.

ptrhahn

iTrader: (9)

Is there any repeatable scenario in which you get the low primary boost? Low speed? Light throttle, hard throttle, from a roll, from a stop?

amp

iTrader: (50)

check ic piping..couplers

RaceReadyRX7

Mostly from a stop, but also any gear while moving with hard throttle. Light throttle I don't expect full boost. Wish I could narrow it down to a specific scenario, but I can't

RaceReadyRX7

I have check all the couplers. Wish it was that simple.

ptrhahn

iTrader: (9)

Do you hear your BOV or CRV fire when you let off? If you get back on the gas after letting off, is it generally fine?

ptrhahn

iTrader: (9)

Also... have you changed/installed anything recently?

RaceReadyRX7

I have a HKS BOV that sounds when the boost is working probably. The other sound is something else. I thought it was the throw bearing at one time, but I hear it even when I'm not using the clutch.

RaceReadyRX7

Nothing new since I added the front mount over year and half ago. Every worked great untill two months ago.

areXseven

iTrader: (1)

Check for a pinched or busted CCV vacuum hose.

Mahjik

iTrader: (1)

Yep, don't forget to check the Charge Control Solenoid:

http://www.autosportracetech.com/RX-...leshooting.htm

RaceReadyRX7

Great link. Thanks.

turbojeff

iTrader: (30)

Hey Steve!

What's up, you ever coming auto-xing in Eugene anymore?

Anyway I had a similar problem, one of the hoses down on one of the actuators (big ones near turbos, I forgot which) had a small slice in the hose.

The second turbo worked just fine, the first didn't produce any boost.

RaceReadyRX7

Hey Jeff,

I hope to get back down there again. Have to fix my problem first. Maybe my wife will let take her new Acura TL.....NOT.

I replaced those hose when I installed the front mount. I will check them when I get home.

BigIslandSevens

iTrader: (4)

Sometimes the CCA that is in the y-pipe gets "sticky" This will cause the flapper valve to hang open and create very low boost on the primary.

Sometimes the rubber valve inside the CCA gets old and cracks. (Causing the vaccum and pressure action of the valve to not operate properly.)

This is more noticeable while under throttle, shifting and getting really low boost. I get around it by "pedaling" the gas once and the valve snaps shut.( Audibly, and a big increase in power.)

Something to think of maybe. It dogged me for a long time until I just risked it , bought the CCA and it was fixed.( The inner valve was bad)

speeddemon7

a cut charge control solenoid vacuum line will cause the ccv not to open and will make a booo sound.
Although Your primary isnt boosting right so it must be something simple.Check all of your c clips as I had one fall off my wastegate door and I would get very little boost at all.Also double check all of your couplers as one may have a split in it.I had a similar problem when my y pipe coupler had a split because the hose clamp dug into it and eventually cut it.Take all of your couplers off and stretch them out.Also check all of your gaskets for some oil residue along the seams.If you find some consider it a boost leak.

ptrhahn

iTrader: (9)

The sound he's describing when he lets off sound like compressor surge... could the primary be trying to boost through the secondary and surging it if the CCV was left open?

RaceReadyRX7

I did the simply test yesterday from http://www.autosportracetech.com/RX-...leshooting.htm The CCV rod did NOT pull in when the engine was running. It did pull in when I connected a vacuum pump to chamber A. Both hoses to chamber A & B are in like new condition. I don't know what to make of the CCV now.

I cheked all the couplers and the other solenoid for loose or missing clips. NPF

Mahjik

iTrader: (1)

Check the Charge Control Solenoid on the rack.

Mahjik

iTrader: (1)

Actually, if the CCV was left open, the primary boost would be getting partially vented through the CRV until around 4000 rpms when the CRV is closed. This would cause low primary and then full secondary.

Since it's more boost going through the CRV with the primary boosting through there as well, it does make a nasty sound (don't ask me how I know).

areXseven

iTrader: (1)

That explaines the low primary boost. The flap is not closing or creating complete shut-off in the Y-Pipe. Most of the primary boost is venting into the Secondary Turbo and out through the intake.

Do as Mahjik advised and check your CC solenoid.

RaceReadyRX7

Is there a way to test without removing intake manifold? I can't even see the CC Solenoid.

Mahjik

iTrader: (1)

Nope. Unless you are a magician, this is a "getting the hands" dirty one.

Klar

God the search button is great.
I had this problem on the way to work this morning. It happened twice: once when I slowed down so a car in front of me could turn. As soon as he was out of the way I down shifted to third and did a pull. Shifted back to fifth and it felt like it hung. I looked at the boost guage and saw only one psi. Let off and back on I heard the valve snap shut and everything worked fine again. Later, just before I got to work, I turn my last corner and did a second gear run. When I shifted to third it did it again. Fixed with modulation of gas pedal.

I don't have my tools here at work so I can't take my car apart. But I think its the valve since we had a cold snap last night. But I have one extra sil I can move around I think. If not I'll probably order both the sil and the CCA.

dgeesaman

iTrader: (7)

See if the CCA moves freely (snaps back) with both hoses disconnected. If it moves slowly, then try taking it apart (carefully), cleaning/greasing, and reassembling. Then, test the actuator diaphragm by seeing if it holds pressure on the pressure side, and vice-versa on the vacuum side.

I pulled the whole y-pipe assembly to do it. After cleaning, it moved nice and snappy. Just be sure you have the valve door oriented the same way on reassembly. Given that it started in cold weather, I suspect it's getting gunky.

Unless you don't mind putting the money into a new CCA, this is a pretty easy fix.

Dave