Liemoanh

Finally I notice whats going on with my boost, I think. Every single time I start the car the turbos don't come on at all, no primary or secondary. The only way they come on is for me to make them come on. I have to floor it in any particular gear to about 5000+ rpms to start to hear it spinning really loud. If I shift to the next gear or if I let off then floor it again in the same gear the boost comes on at 10 psi, then if I keep the gas floored the boost will stay at secondary 10 psi, untell 2,3,4, 5th gear. I notice that while I'm flooring it the boost will stay at 10 psi while the rpms are above 4500 rpms. If I let it drop below 4500 rpms no more boost, that's one thing I notice. Second is that when I do the 5000+ rpm thing to get the turbos on, I notice that if I shift and let the rpms drop below 4500 rpms I get 10 psi of primary boost, once I hit 4500 rpms while on primary boost the boost drops to 5 psi and then 2 psi by 5000 rpms and stays at 2 psi tell redline. I've been reading alot and I think the rod is the thing that controls which turbos gets boost. What controls the rod? Because I don't think it's switching like it's suppose to. Also when I start the car why does'nt it move back to the primary, because I think it's stuck on the secondary, which in turns brings me to the conclusion of having to floor it 5000 rpms which is in the secondary range. Somone please help. I've been dealing with this ever since I got the car, which is about 1 year now and have spent enough money on this turbo problem to basically buy me a single turbo. I can't take it no more. Thanks for your inputs!

Fd3BOOST

iTrader: (7)

The secondary turbo comes in line at 4500 rpm. If your getting anything other than 10 psi after that you have a boost leak period.

You can check the pre control actuator arm if you want but I dont think thats your problem. There is a clip on the bottom side that I guess could have somehow came off but it's not likely.

Liemoanh

Thanks for the reply, but I do get 10 psi. I don't think its a boost leak because I get the inital 10 psi. My point is that if I get the turbos to come on, and if it comes on after 4500 rpms the boost will stay at 10 psi, and if I let off the gas but still keeping it above 4500 rpms and then floor it the boost will jump right back up to 10 psi and hold at 10 psi untell redline. If I let it drop below 4500 rpms the boost won't come one meaning no primary turbo. Then if I make the turbos come on again by doing the 5000+ rpm thing then shifting to the next gear and letting the rpms drop below 4500 rpms then the primary boost will come on at 10 psi. The primary will then stay on tell the rest of the drive. So if I'm on primary boost and gun it past 4500 rpms the secondary gets no boost, but if I'm on secondary boost and let it drop below 4500 rpms I get no primary boost. So basically what controls the switching of the turbos from primary to secondary, or from secondary to primary. Thanks for your help?

Liemoanh

Please help I'm almost there.

Rated R1

Your secondary turbo does not work unless you get primary boost. This is an excellent page to troubleshoot boost problems and it also explains how the control system works. If you haven't checked it out do so.

http://home.iSTAR.ca/~dvandit/turbocharger.htm

cymrex

iTrader: (2)

I had the same problem. I had taken the car to 3 rotary specialists and none could find the problem. They kept patching things up rather than fixing the actual problem.

The root of my problem was the Charge Control Valve, the one in the back half of the y-pipe, was staying open. This causes the primary turbo to spin the secondary backwards when there is not enough exhaust pressure available to the secondary turbo to keep it moving forward. Or when the Charge relief valve is open all of your boost is vented. Below 4500 rpm the turbo control actuator is limiting the amount of exhaust provided to the second turbo. Also the charge relief valve can be open venting all of your boost. Now for the solution, double check the vacuume system. It provides vacuume to the Charge Control valve. Check the vacuume chamber for leaks. Also check the check valve from the vacuume chamber to the UIM that it does not leak and is oriented the right direction. Check the function of the Charge Control Valve. The specs are in the service manual. I had a switched vacume line that was not supplying vaccume to the chamber causing all of my problems including multiple turbo rebuilds.

Hope this helps. Pm me if you want to talk.

Liemoanh

Thanks alot cymrex. Funny thing is that I took my car to Rotary Specialist on Rartian Rd in Denver and they did'nt know whats wrong and basically gave me a bill of $1,000 and still know boost. Anyways when you had your problem did you even get primary boost? When my turbos are not boosting and when step on the gas I could hear a very faint spinning, then nothing and no boost. Have you experience this. How can I check if the charge relief is getting vaccum? Also all my check valve blow one way but the it you have to blow on it kinda hard. Also I notice that when I floor it to 5000+rpms the turbos start spinning really load but the boost gauge shows the needle at 2 psi, once I start to hear the turbos spinning the needle drops to a vaccum of -1 then shoots up to 10 psi. Have you experience this? Please respond

cymrex

iTrader: (2)

Rotary Specialists is one of the mechanics i had look at my car when I could not figure out the problem.

Here is a typical scenario before i fixed the problem...
Start the car and warm up.
First acceleration run normal 10-6-10 (I live at 8100 ft so the low transition)
If I drop below 3000 rpm i would have 0 - 3 psi of boost, let it drop to vacuume. Go on another run and at 3000 rpm the boost would jump instantly to 10 psi causing the rear tires to squeal or break loose. Sometime I could not manage more than 3psi ever, until I would drop to vacuume.

When is your jump to 10 psi? Do you get a normal pattern right after starting and warming up? You are local so I could come see if I can find the problem. PM me your telephone number, maybe we could look at your car together.

Kahren

iTrader: (13)

your wastegate actuator might not be functioning properly check that out. u can find a shp manual here www.iluvmyrx7.com

P'cola FD

Hook a boost gauge up to a nipple coming right off of the y-pipe. That will tell you if you're getting boost from the turbos but it's not getting to the manifold. If it reads 2 psi on the primary, then hook a gauge up to the nipple on the y-pipe between the secondary turbo and the charge control valve. There should not be any boost at that nipple until 3,000 rpms.

Liemoanh

Thanks for the reply. Thanks cymrex for the offer but I recently moved back to San Diego about one month ago. I wish I sould of meet you sooner. Anyways when I start the car in the morning or when its fully cold and I make the turbos come on they come on but won't hold. I notice that if I drive awhile after reaching operation temperatures then floor it, it will come on then hold and stay on for the rest of the drive. Somtimes if I'm boosting alot and then shut off the car, then turn it on again within a 5 minute spand. The turbos will come on without me having to make them come on. The longer it sits the less of a chance they will come on automatically. As of right now I only using primary boost for all my drives. Today after going for a test drive, I floored it in second gear, nothing all the way to redline shifted to third and let the rpms drop to about 3000 rpms floored it to about 5500 rpms still nothing, I let off the gas and the rpms dropped to about 4000 rpms, then floored it again. Nothing untell 4500 rpms then the boost gauge shoots to 10 psi really fast. I took the 10 psi to about 6000 rpms the shifted to fourth, then let it drop to about 3000 rpms then primary was on. It stayed on for the rest of the drive. I going to try everything you guy say, but I just need to know what to do. I'll try what P'cola said and tell you what happens. Hey Cymrex what was your solution to your problems. Mine sound very indentical. Also I had a shop recently replace the TCS, and the vaccum chamber under the altenator. Shop said they don't know whats wrong. Anything else I sould do???