Won't make boost(Update and resolved!)

Ok

On my third turbo now. Bought the car with bad turbo seals(Turbo 1). Smoked like hell.

Buy a used turbo(Turbo 2). Put in on. Make 7 pounds of boost once to a loud noise. Pull over everthying looks fine. Won't make boost anymore. Examine it next day and the nut tightening the compressor blades to the shaft isn't tight. Seems as though the shaft is spinning inside compressor blades. Tighten the nut. Still make no more boost. When i check if the nut has loosened again, it hasn't its TIGHT.

Buy 2nd used turbo(Turbo 3). Begin to remove first used replacement. Notice that where the wastegate bolts up to a bracket on the right side of the turbo(also where some coolant lines bolt up to a bracket) IS NOT bolted up. Think, holy carp this musta been why i wasnt making any boost. My wastegate was stuck open. Decide to replace with Turbo 3 anyway b/c its in best condition with hardly any shaft play at all. Replace it and get everythign hooked(besides downpipe to the under car exhuast) up and go to drive the car. Don't make any boost! Boost gauge read 1 pouond a couple of times compared to turbo 2 that never read above 0. It almost sounded like I could hear some spoolng but with this exhaust disconnected the car was so damn loud i'm not sure.

I'm at a loss and am getting turned off on working on this car. Its been my dream car for so long but I've had no luck so far. Help me regain my love!

Questions and ideas I've come up with.

When I bought the car, looking at the wastegate it has TWO nipples on it. One of them has a vaccum hose going off of it towards the firewall. The other one is plugged. What is the second nipple for? (This was like this on while Turbo 1 was on the car and I DID make boost)

Also to determine if wastegate is faulty: is it a good idea to pull vaccum hose that goes to wastegate and do a 3rd gear pull higher up in the rpms to see if i start to make a slight amout of boost up high in the RPM's. Reason I say 3rd gear is so that I can somewhat controll the boost with the throttel and will be less likely to overboost.

All your help is greatly appreciated.
Mark

forgot to mention that car has a Greddy Profec B boost controller installed. This was instlaled when I bought the car and I know nothign about the instalation. For all i know, being ignorant of this may be hurthing my abiltiy to diagnose my 0 boost issue.

I did have boost gauge both turned off and on to see if it made a difference. Shouldnt the car make stock boost with the boost controller turned off even if somethign is messed up with the boost controller(such as the solenoid going bad)?

For your wastegate nipples...the one pointing towards the firewall should be the one capped and the one pointing out towards the front is the one that is plugged into the compressor housing on the stock ct26. Since you said that you have a profec b...the nipple that points out to the front should be going into the compressor housing. I forget which side goes to which on the selenoid, but the compressor side nipple goes into one side of the selenoid and the wastegate nipple said before goes into the otherside of the selenoid. I think it's NO and COM on the selenoid...just have to figure out which line goes to which one on selenoid.

To determine if wastegate is faulty or not, I would just unplug the vacuum line that goes to intake manifold from boost sensor so the car can just boost whatever it can. Take it onto the onramp on the freeway hard or long empty straightaway for a pull or two to see if boost goes up at all. If not I would change the wastegate from your original turbo with the car to your third turbo and see if it boosts any better.

The COM goes to actuator (the nipple that point toward the compressor housing)
The NO goes to the compressor housing
The other nipples on the actuator that point away from the compressor must be capped. (without boost controller, this line must go to VSV)

You might want to isolate the boost controller by physically disable it.
To do this, just bypass the solenoid by connect the nipple on the compressor housing to the nipple on the actuator (one that point toward the compressor). You can cap the other one. If the actuator is OK, it should boost to 7-8 psi.

If it doesn't boost at all, it might stuck open.
Try moving the wastegate arm with your hand.
To test if the spring or diaphram went bad, with engine off, apply pressure to the nipple that point toward the compressor housing, while capping off the other. At more than 7-8 psi you should see wastegate arm moves. It should return back to original position when there is no pressure.

Ok

The nipple off of the wastegate pointing to the firewall is capped. The nipple off the wastegate pointing to the front of the car has a vaccum hose going towards the firewall. The nipple coming off of the compressor housing ALSO has a vaccum hose going off of it towards the firewall.

For your wastegate nipples...the one pointing towards the firewall should be the one capped and the one pointing out towards the front is the one that is plugged into the compressor housing on the stock ct26. Since you said that you have a profec b...the nipple that points out to the front should be going into the compressor housing. I forget which side goes to which on the selenoid, but the compressor side nipple goes into one side of the selenoid and the wastegate nipple said before goes into the otherside of the selenoid. I think it's NO and COM on the selenoid...just have to figure out which line goes to which one on selenoid.

Click to expand...

So are you saying that the nipple off of teh bellshaped wastegate thing that points forward should have a short vaccum hose that goes direcly to the nipple on the compressor housing? Or did you mean to type on stock CT26 with no boost controler it does that but NOT with the Profec B. Seems like you may have accidently typed the sentence about the nipple from wastegat pointing forwards going to nipple on compressor housing.

If that is what you mean it sounds like I need to find out where the two hoses go. Sounds like both the one coming off the nipple of the compressor housing and the forward facing nipple of the wastegate should go into my (boost controllers?) solenoid?

If thats is my corrrect understanding maybe I have them mixed up. Should I try switching them around?

Gary":2yecqhlf said:

The COM goes to actuator (the nipple that point toward the compressor housing)
The NO goes to the compressor housing
The other nipples on the actuator that point away from the compressor must be capped. (without boost controller, this line must go to VSV)

Click to expand...

What do you mean when you refer to the "actuator" Also can you please identify the "COM" and "NO". I have no lines going from the bell shaped wastegat nipples to the compresor housing nipple. Seems from both of your ideas this is wrong. Sounds like only thing I have correct is the nipple facing rearward capped because it usualy goes to the VSV, but I have a boost controller and that prevents the need of it.

You might want to isolate the boost controller by physically disable it. To do this, just bypass the solenoid by connect the nipple on the compressor housing to the nipple on the actuator (one that point toward the compressor). You can cap the other one. If the actuator is OK, it should boost to 7-8 psi.

Click to expand...

Almost sounds like you contradict yourself here saying that the nipple coming off the compressor housing is currently going to the boost controler and to isolate it put it directly to the nipple on the wastegate.

If it doesn't boost at all, it might stuck open.
Try moving the wastegate arm with your hand.
To test if the spring or diaphram went bad, with engine off, apply pressure to the nipple that point toward the compressor housing, while capping off the other. At more than 7-8 psi you should see wastegate arm moves. It should return back to original position when there is no pressure.

Click to expand...

I have tried moving the wategate arm with my hand. It is stiff. I assume this is a good thing. As for testing with air pressure I don't havea any acces to an air hose as of current.

Your car has the Profec B installed and it doesn't boost.
The best way to diagnose is to bypass the Profec B.
It seems you do not clearly understand the basic of how wastegate and boost controller work.

Here we go:
The wastegate is a device that controls boost. In this case, the internal wastegate in our car consists of wastegate actuator (the bell shape thingy), wastegate arm, and wastegate door (flapper) that locates inside the turbine housing. Inside the actuator, there is a spring that push arm and make the door shut. The actuator detects pressure from the compressor housing and if the pressure overcome the spring (7psi or so), it pushes the arm and make the door open to let the exhaust bypasses the turbine, hence, limitting the boost.

The wastegate actuator has another port that connect to the VSV. When VSV opens, it releases the pressure inside the actuator and fool the actuator that the pressure is less than 7 psi. This lets the car boost over 7 psi in some condition.

Now, the Profec B boost controller has a solenoid unit. The solenoid unit must be install "between" the compressor and the actuator in order to manipulate the pressure to the wastegate actuator.

In your current setup, this is why you see two vacuum line goes to the firewall, where the solenoid unit is mounted. The COM and NO, I mentioned earlier are the ports labelled on the solenoid unit.

I recommend you to isolate the Profec B from your system and return it to stock setup by hooking the compressor and the wastegate actuator with a vacuum line. This way you can see what where problem really is. If the problem persist, it's your wastegate. If the problem is fixed, it's the Profec B that prevent the boost.

check the 2 post down for a pic of turbo, the nipple with no hose goes to the turbo vsv http://www.alltrac.net/phpBB2/viewtopic.php?t=2618

nice pic gary

Here it is



Note: I edited Rob's pic.

Gary always have the answer hehe

But yes on ct26 w/out boost controller the front facing nipple on wastegate has a short vacuum line that connects to nipple on compressor housing as shown on the pictures Gary posted.

On Ct26 w/ boost controller, the two nipples does go into the selenoid like the pictures Gary posted as well. Trace the vacuum lines from compressor housing and wastegate to see where they end up at towards the firewall, they're most likely connected to the selenoid of the boost controller.

Also, there's also a vacuum nipple that is located near the coolant lines for the ct26 beside the block...very hard to see unless you know what you're looking for. It's pretty much under the tmic if you still have it, that nipple also needs to be capped off as well. So the one on wastegate facing firewall needs to be capped and the one nipple across from it needs to be capped off.

Aweseome! Thanks so much everyoen. Your help is greatly appreciated. I haven't had a chance to get out to work on the car just yet but will go and try these things here in about 30 minutes.

Even if they don't help me solve the problem I no doubt have a better understanding of how the boost controller works with the wastegate!

**One thing I just thought of, back when I had Turbo 1 on the car I was messing with the radio one day. The Boost controller main unit is located right under the radio. After installing everythign I remeber hearing a whipsing sound while boosting in car from around that area and was getting a boost leak. I think a hose may have come loose or completly off of that. I'm going to check that first.

Ok everone

Just isolated the boost controller out of the problem.

Connected the nipple on compresor housing to forward facing nipple on wastegate. Still made no more than 1 pound of boost.

Things to note:

As I mentioned about hearing a whisping noise in the cabin. When I went for this test drive I had the boost controler out of its pocket sitting on the middle console. You can hear and feel a EXTREMLY SMALL whisp where a SMALL amount of air is coming out of the vaccum hose into the back of the boost controller. One hose leaves the rear of the boost controlelr with a T-hook up where one goes to the aftermarket boost gauge and one appears to go throuh the firewall.

The hose that connects the intercoooler to the throttle body has a rip in it. When the clamp is tightned down on the hose NO air escapes. Here is a picture of me spreading it open with my fingers.

well you are going to need a new one if you want to build boost. in the mean time black tape the crap out of it,reinstall then check for boost.

I honestly don't think that is affecting it at all! When the clamp is tight you seriusly can't even notice that there is a crack.

I do intend to get a new one though

Honestly, it may seem that it will not be leaking from there...but I'm sure it is slowly that's why you're not building boost.

actually, mine is ripped too, but i still make full boost. however, replacing it won't hurt, it could be a contributing factor.

MADE BOOST! YAY

Ok, i had to disasemble the whole thing b/c I was leaking a litle oil. Thought it was b/c of my oil line not being quite right on the underside of the turbo.

In the process I put a new exhaust manifold gasket on(old one was past shot) and redid everythign quite meticullously. I also used a different wastegate. I dont know what exactly was the culprit last time but it works now!

After driving it I see that I still have the oil leak though . It doesnt look like its coming from the oil line into the turbo though. Looks like its coming from the back of the engine bay. Not sure exactly where.

So, I"m a lot happier but:

1. Need to isolate and fix that oil leak
2. I have a small boost leatk but its real small and I know a couple of culprits so I'm not concerned.

Thanks for everyones help.

Mark

woot good job mark.

8) , I too had this prob, nice big crack in the inlet rubber where IC conects to, solves by custom making a new one, now no leeks, and yes that bick crack can kill the boost big time.
:smokes: