ATPRX7

Hey, I just tested both my actuator, and my solenoid, and all the lines in between, and they all tested fine, but the thing is, when i did the test on Istar's turbo troubleshooting site, and reved it to 5000, but basically the actuator did not move, even though everything in that system tested fine? What could be the problem?

Thanks,

Ravi

Blue-GTU

Let's forget Istar's site for a sec, and get down to what's going on.
After all your testing, where are you now? What are your symptoms?

If you could list every single test that you have done, I think us sequential adicts can help a little better.

ATPRX7

my symptoms is a boost pattern of 11-7-5, and I have narrowed it down to my turbo precontrol actuator not moving at 4500!

spooledUP7

Get your self some T adapters and lets start doing some test.

Tee your boost gauge into the nipple that is on the back of the Y-pipe just behind the Charge Relief Valve's (CRV) hose connected to the Y-pipe.

Go for a drive.

This is what I saw on my car with this test (My car is 11-8-11 boosting)

3rd gear - WOT

2000 RPM - 0PSI
3000 RPM - 0PSI
3500 RPM - 0PSI
4000 - 4500 RPM - Rolled up to 8 PSI +-1PSI
4500 + RPM 12PSI

What is happening: Page F-84 in the manual

0-4000 RPM -
Precontrol controlled by ECU,
CRV off (Venting)
Charge Control Valve on (closed).
Turbo Control off

4000-4499 RPM -
Precontrol Optimized by ECU,
CRV off Charge Control Valve on (closed).
Turbo Control off

4500 RPM -
Precontrol fixed (5% open)
CRV on (closed) and Charge control valve off (open)
Turbo Control on

If you are getting anything close to what I saw with my test, then you can rule out that your precontrol is not working. This means that you should see a build up of boost just before 4500 RPM on the secondary turbo.

If you don't see any boost before 4500 then you may be right, the precontrol is not working.

If you notice in the above breakdown, the turbo control is off before 4500 RPM. The Turbo Control Actuator is the flood gate to the secondary turbo, and if shut, you will only have the fixed 5% of the precontroller pushing the secondary turbo. Does this seem like enough to move 10 PSI? No.

So, if your Turbo Control Actuator is not directing exahust gas to the secondary turbo then you will be facing a sympton such as:

Loss of boost on secondary turbo.

ejmack1

THanks for that post that was very helpful i think there are enough of us on this list with that problem....

ech

do we know that the stock system will bother to go into parallel mode if there is no load?

also just the pre-control actuator alone shouldn't cause low secondary boost. It could cause low primary boost if it doesn't shut <3000 and it can cause a bad transition if it isn't open 3000-4500 - but >4500 it it's open it shouldn't really matter that much should it? The charge is already going to both turbos.

just a thought...

ATPRX7

I just did that test and what happened for me is that I have a 11-7-5 boost pattern, and in that test there was no boost until 4500. when I got 11 psi on the secondary.

So what is my problem? ejmack?

Thanks,

Ravi

ATPRX7

But i thought that with the CRV venting before 4500, there shouldnt be any pressure in that Y pipe before 4500? With the CRV venting fine, why am i supposed to be getting boost before 4500?

Mach2

ATPRX7,
Just a thought, but did you check the small 1" hose that is attached to the CRV and makes a 90deg bend into the y-pipe? I had a similar problem and found that the hose had a slit in it. Check it out. Also the reason why you should see "some" boost before 4500rpm is because the secondary is prespooled before coming online. If it weren't then it wouldn't be able to come on seamlessly at 4500rpm. I think that you should start seeing some positive pressures in that hose around 4000rpm and should see 10+ psi around 4500rpm.

KZ1

no boost is built by secodnary turbo until 4500 rpm, it is only pre-spun, the boost is vented via the CRV, so I don't think that test is worthy of saying wether the TPC is working, because I don;t think you woudl see any pressure at all., now if you plugged up the CRV and did it, okay.

Mach2

KZ1,
You're absolutely right. I wasn't thinking when I posted. Anyway ATPRX7, you should check that hose that I mentioned.

spooledUP7

Dude, you guys, do the test. Bond007 turned me on to this. You will see boost pressure when you T into the nipple. The CRV is venting, but there is boost. Do the test. I did the test.

ATPRX7

so what is with my symptoms, 4500-redline i have 10-11-12 psi with this test, but when i have my boost gauge hooked up normally i am only making 5 psi past 4500! What could it be!?!

Thanks,

Ravi

Lunar7

I've also been experiencing low boost on second turbo ( 11-8-8 ).

Thanks to this thread and advice from Mach2 I just discovered that the very short hose from the Charge Control Actuator to the y-pipe had a pinhole crack. That hose is buried kind of deep (its under the CRV) so its hard to see.

I'll be replacing it this week and hopefully it cures my problem.

Thanks Mach2

KZ1

I am sorry I don;t understand what you are getting at.

Spooled, I am sure you will see some pressure, but 8psi??? I don't think so. I just think you made mistake in typing. I like the test, just 8 is high, I would expect maybe 1 since CRV is venting, not even 1. Unless of course I misunderstand where you are saying to T into, what line does it T into? (name of actuator swlenoid please)

spooledUP7

Ok, bond007 help me out.

Yes, T into the Charge Control Solenoid Vacuum hose that is the furthest back on the Y-pipe. It is behind the CRV hose. I know that there is a charge control valve with two hoses on it, and that it may be confusing to say "Charge Control" but the hose that I am describing is the "third" hose most visibly involved with the Charge Control system.

So, before you dismiss the chance of any boost ( I was the same way until bond007 asked if actually tested it) try it out. It's simple to do, and the results are totally backwards from what you would think, but there will be boost up to and perhaps beyond 8psi before 4500 depending on how quick your secondary spools.

It's confusing, I know, I thought that a smaller pill on the prespool side would increase prespool, but I was wroong about that. Give it a whirl.

ATPRX7

ok, so when you do this test, what are the results supposed to be? Boost is supposed to be what to what?

Thanks guys,

Ravi

spooledUP7

The test is to figure out if you are getting any prespool based on Teeing your boost gauge into the y-pipe secondary only. (See above)

I saw boost rising at 4K up to 4500 with a max boost of 8 psi just before 4500RPM.

Some claim boost starts at 3K, but on my car it was 4k.

At or after 4500 I got 12 psi.

My persistance with this test was fueled by KZ1 having trouble believing that you would see any boost due to the CRV venting. I think it's funny because I was with the same mind set until I tested it myself.

Off the subject:

I get often get 11 psi at the manifold, but normally 10 psi. I'm not sure if 1 psi of pressure drop is right for a stock IC, but I am guessing it is.

ATPRX7

Prespooled7, i have a question, Ok, when i Teed in the vaccuum line at the Y pipe, I got 9-10 at the transition and then up to 13 past 4500. Ok, when my boost gauge is connected at the manifold, I get a boost pattern of 11-8-5 at the manifold, does that mean the butterfly on the y pipe is not opening? because when i test it with the KOKO it does work? What can this mean?

spooledUP7

prespooled7 is funny.

If I were to get that same result I would be curious if charge control door is actually opening. I would T into the charge control actuator. There are two hoses. I would choose the vacuum side for my T hookup. I would use my vacuum gage and go for a drive.


On page F-84 of the shop manual, the operation flow chart shows that the charge control is on at prespool, and then turns off at combo boost. This means that there should be vacuum at prespool and no vacuum at combo. But..is it really 0psi when the
switching solenoid switches to off?

On the same page, there is a diagram of the turbo system, and it shows the charge control solenoid, the electronic switch, is connected directly to the nipple I talked about earlier for performing the prespool test. The diagram shows that when the switching solenoid changes from the vacuum source it switches to this hose attached to the back of the secondary turbocharger Y-pipe. Common sense would say that the charge control actuator is now being bombarded with the pressure built from the turbos. This would make sense in forcing the door open.

Now, if there is a leak in this path, one could speculate that the door would not be able to stay shut as well as it would with pressure holding the door open.

Add on top of all this, there is a second line going into the charge control actuator that is pressure activated. It is on the primary side of the y-pipe. If the pressure from the primary turbo is trying to hold this door shut, then a leak on the other line could mean that there is a battle going on with the door.

chew on that!

This is all theoretical mind you.

spooledUP7

Not sure if anyone cares, but I decided to test my previous theory on the Charge Control actuator.

I teed into the vacuum side of the charge control actuator with my boost gauge.

here are the results:
Description Result control action
Car on - Vacuum up to 25 inches - Door shut
750-4500 - Vacuum - Door shut
4500 + - Boost up to 12 psi - Door open

What good is this test?

Tells you if the charge control door is getting the needed pressure to stay open.

That's about all the use I can see of this test. The problem with this test is that it doesn't really show if the door is open, just that it is getting the boost to open it. You would need to rig up some sort of contact switch to really know if the door is fully opening.
Not to hard to do since there is set screw that the fulcrum door rest on at full open.

aReX-7

iTrader: (3)

I was just checking out the thread and thought I would share my recent experience in a closely related area.

I bought a second 3rd Gen a couple of weeks ago that was getting little or no boost past 4500 rpm. After checking all vacuum/pressure lines and actuators, I finally decided to test all of the solenoids. Sure enough, the turbo control solenoid that is bolted to the air control valve was toast. I had been given the impression that these solenoids did not fail very often, but when I ordered it from Tim at Mazda Comp. Parts, he said it is a common order. Just thought I would pass it along!

I am keeping my fingers crossed that this is my only problem.

Happy Rotoring!

KZ1

guys, this is getting way to complicated.

you shoudl see the Charge control valve (CCV) rod pulled in with key on and vacuum in tank. if not, turn key on and pull of hose to see if you hear hissing. if not, go to the slenoid and check for operation. if you do, double check valve is fulty by applying vacuum manually with pump. That will cover and assure you CCV is working. Remember, there are only a few items that contribute to secondary boost (main ones) TCA, WG, CCV, CRV. that is it. others could be fucked, but you shoudl still see secondary boost.

I still have no idea what nipple (hmmmm... sory guys) prespooled7 is talkaing about, can you tell me what it accesses? is it in y-pipe before or after CCV?


BTW let's assuem prespooled's test means secondary is producing boost, then the ONLY thing it could be would be the CCV. oh yeah, stock intercooler drops about 2psi if I rememebr right 2.64

Philip


Guess what I saw yesterday for the first time. 12-12-12, hehehe

spooledUP7

KZ1, Prespooled7 was funny the first time.

Too Complicated? Maybe, but I tend to be complicated and neurotic when it comes to complicated issues.

To say that there's no need to look further than common sense is like saying that the world would have been better off without spam.

My non-conventional perspective on the sequential turbo operation is a spin off (no pun intended) of the discussion normally found in issues such as this. My attempt is to bring a visual description of the actual function to the acronyms we throw around to describe our diagnostic awareness. We could preach all day about the TCA, CRV, BOV, CCA and MIA affecting the sequential turbo setup, but who really goes, ahh, that makes sense.

Not me. I need the visualization of function. I need to know what happens when the switch switches, and what pressure presses on what valve. Did you know that there was boost in the second turbo before 4500 even though the CRV is venting? No.

Did you know that the Charge Control Door is forced open not only by vacuum but by pressure and in the same hose? Probably not.

Do a search on the forum for this kind of detail.. You won't find it. Nope, just. the mundane and safe replies of; Your TCA’s not working, leaking check valve, or you must not have your muffler bearing on tight and so on.

So, dig the depth. learn something, or add something, but please don't simplify the complexity.

bond007

Spooledup7: You seem to be on here more than I. Feel free to e-mail if you get any issues (it is in my profile), that are out of the ordinary or don't get solved. I still know a few things that most people have yet to ever mention on here or the big list :-) I just need some time to make up a webpage, but other things keep me busy. Your thinking seems okay. Keep it up.

Others: Why I don't like this format - advice gets lost. Especially when troubleshooting, e-mail is best. I've kept in contact with 2-3 guys working on low transition over 3 months now. We are almost there (they can't tinker everyday). Here, it seems like if an issue is partially solved, it doesn't come back up as a recent topic...or comes back ever again, and the poor fella with the problem is still stuck....

Anyhow....that is my $0.02

Next: I'm at MADS. If I'm not too busy tearing up VIR in my "stock" car, I'll be happy to talk turbo troubleshooting.
Red FD, license plate Bond007

My background: Simple. Spent 1 year under the hood chasing boost problems in my car at various stages of disrepair, and later other folks' cars locally. 'nuff said - I know this stuff cold, and colder than nearly anyone else (not to be egotistical, but it is pretty darn true....I get a lot of mail on the big list for help and am batting 1.000 for those that reply back and actually stick through troubleshooting)

I'm a big lister, and just roam the single turbo section here. I don't mind helping out an intelligent question, but honestly, folks - read the FSM, and Derek's FAQ and do some thinking and diagram drawing/tracing. It is the only way to learn the turbo control system.

The turbo control system isn't hard. It is just a PITA to get to the "MEAT" (solenoid rack). If that wasn't the issue, most boost issues would be solved quickly. Actually, I can pull the UIM in about 10minutes <grin>. The funny thing, is that the meat (if already silicone and wrapped) doesn't fail too often. Yes, you get a dead solenoid, but you can detect them without pulled the UIM.

So, I've skimmed the thread, and it seems like most are getting the gist of things and how to "troubleshoot" - it is a fine art, and not hard to master.

One more time: READ THE FSM! There are two diagrams of the turbo control system in there - the "complicated one" and the functional one. That should help explain things. Both are on the web.

If you are having transition problems, and in this case, it is a loss of boost above 4500, I've troubleshot/determined:

1) A BOOST LEAK! They happen such that you get 10psi primary, and zilch or low pressure secondary. How do I know? That is what spun my head around for several months of the 1 year - I did too much maintenance at one time (leaking turbo oil lines, didn't replace y-pipe gaskets = disaster)
2) Turbo control not coming online - highly suspect for 3-5psi after 4500
3) Charge control not opening up
4) Charge relief hose (well, this is #1)
5) Leaking BOV or CRV
6) Gaskets or couplers
7) Bad turbo (I just troubleshot this one....yesterday....) but that was for 0psi everywhere (and HE DIDN'T want to LISTEN and do my testing philosophy for 2 weeks). I kindly replied to his responses and asked him to test this/that. Never tested. Kept asking questions. Finally, he listens....and there it is....
(again, I'm not trying to toot my horn, but I'm well versed in this area of the car, more than I care to be....)

One of my pet peeves is going back over your work AGAIN, another day especially in daylight, to see stuff you don't see in the wee hours of the night, when your brain is "slow".

I also don't see any verification of the BASICS (#1/#6 are a BIGGIE!)

Call me when you've gone through the above list, then we can talk about why your car isn't acting right. Boost pattern is a symptom. Hey doc, I've got a fever....is it bacterial? a virus? etc....etc....each requires a different medicine.

Same here.....

Check the subsystems, and do it WHILE DRIVING the car and it is hot! It isn't the same sitting cold in the garage. Teeing into lines will help you a lot more than pulling the whole solenoid rack and testing it cold. That is unless you know some tricks and have experience some VERY STRANGE FAILURES (ahem, been there done that....do it in the car to avoid this)

I still have more tricks up my sleeve, but I doubt they will be needed if all of you boost problem "owners" check this list and listen to spooledup7 or me. (He?) seems to know a good bit about things and is willing to go out and empirically determine what is going on (stick hands in hot engine bay!) - I LIKE THAT!

I'm not gonna proofread, I'm tired, if I botched up grammar or spelling, sorry...I know better!

a.f.
afarrag@triad.rr.com