dbtk2 Posted July 18, 2003 Report Share Posted July 18, 2003 OK, so some of you may remember my post a few weeks back about the problems we have been having with the turbo on our TGP since we got it, well hopefully you can help me here. I replaced the boost controller, because it made sense that that could be the problem. It did not fix the problem, and the car still runs (according to the guage) 2psi boost (every once in a while the guage will hit a whopping 3psi). So, all of the vacuum lines appear to be correct and everything, and I can't find anything wrong that would cause the problem. I checked the turbine in the turbo and it has no play at all, and there is no oil or anything showing that the turbo is bad, so I think the turbo is actually in fairly good shape. The only thing that I can think of that could be wrong is the wastegate controller that is attached to the turbo. Now, someone told me something about how if you pull the vacuum lines it should run huge amounts of boost and the computer will shut it off due to overboosting, well no matter what vacuum lines I disconnect for the turbo it will still run the same amount of boost. This is what is making me think it is the wastegate controller on the turbo. What I want to know is if this makes sense to anyone else, and if not, what do you think could be wrong. If the wastegate controller being bad makes sense, do you know where I can get one for it? This information would greatly help. Now let me get into the rebuilds. My dad thinks the problem is the wastegate controller, but he is going to send in the whole turbo, which to me seems to be in very good shape, almost like it is brand new, because the place that rebuilds the turbo, rebuilds the wastegate controller also. So he is going to spend $300 to get the wastegate controller rebuilt basically, because the turbo doesn't need the rebuild, or at least it doesn't seem like it does to me. So...does anybody know if or where I can buy one of these new so my dad doesn't fork out $300 for this simple part. Thanks. Shawn Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted July 18, 2003 Report Share Posted July 18, 2003 Test 1 Take your hose of the front of the turbo and don’t drive down a dirt road. This will eliminate any restrictions in the intake side. Check intercooler hoses for tightness. First thing you need to know is it boosting and how much. With the stock gauge you can’t really trouble shoot cause its to inaccurate. Go get a vacuum gauge that also reads pressure (about 10# is what I think they are) at any parts store, 6’ or more of hose and a tee. If you get a female rubber tee you can hook it up on your modulator vacuum line on the front of the throttle body. You will need a barbed hose connector also. Connect it up and get it where you can see it when driving. Tape it to your dash if you have to. Now see that you actually have with the pressure line disconnected from the waste gate actuator. That’s the 2’’ round gold thing on top of your turbo. Basic I know but I don’t know what you know. Keep in mind to raise the boost slowly because you have no protection for over boost other than the spring in the actuator. Still 2# go to test 2. Test 2 Take the actuator arm of the waste gate. The arm in the closed position should be parallel to the exhaust flange or pointing right at you if your looking over the fender. Move the arm and flip it closed. I should make a solid metal clunk when it closes. That will let you know that at least the waste gate is attached to the arm. Now wire the arm closed with like with bailing wire not electrical wire or you will have a sticky mess. The actuator tube is a good place. Make sure the arm can’t move. Test drive but go slow. If you have boost bring it up slowly. You should hit fuel cut around 6-8# unless you have a chip. If it doesn’t hit fuel cut don’t go over 10#. If you are now getting boost then your actuator spring is rotten. If you can’t get boost and you have a turbine wheel in the turbo than you have an exhaust restriction, most likely the cat. You can check that by disconnecting the down pipe in front of the cat. Two big bolts with springs on them. Post back the results. If it is the actuator I have one that about a year old. Save you about $40.00. Hope this finds your problem jud Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted July 18, 2003 Author Report Share Posted July 18, 2003 OK, I do not think it is an exhaust restriction or actual turbo problem for this reason. When we got the car it was OVERboosting. It would get up to ~9.5psi and the fuel cutoff would come on. So we took the car into the shop to get an oil leak fixed, and asked the mechanic if he could look at the turbo and see if he could figure out why it was overboosting. Well, when we got the car back from him, I don't know WTF he did, but the car was only running ~3.5psi according to the guage, and wouldn't upshift into the next gear at WOT, you would have to let off the gas and then it would shift. So we figured it was a vacuum problem. All the vacuum lines appear to be correct so we replaced the boost controller (the one that the vacuum lines run to) thinking it was leaking vacuum, and boost dropped to ~2psi according to the guage, but now the transmission shifts itself at WOT, but the old one looked like it was bad and leaking vacuum so it is probably a good thing we replaced it. Because of this I highly doubt it is an exhaust restriction or a bad turbo. So, I am pretty sure it is the wastegate controller (or actuator or whatever) on the turbo (the round thing that sets on top). I can do some of these test to make sure, but I am pretty sure that is what it is. I will do some of these tests and let you know I guess, but I think that is what it is. How much do you want for the actuator?? Read the original post, that may help you know what is going on a little better. http://www.w-body.com/forum/viewtopic.php?t=5282&start=0 Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted July 18, 2003 Report Share Posted July 18, 2003 Just wire the waste gate closed, you don't have to take the rod off just the clip that holds it on. There is a little grove you can wrap the wire around. You might take the rod off and pull on it you should have stiff resistance. Make sure there is no line to the actuator(yellow thing on top of turbo) the other thing is the waste gate control valve solenoid. The one on front of your intake. You will know the minute you step on the gas. Don't floor it. Do this test and then we can get your vacuum(pressure) lines on correctly and check out your solenoid. $50.00 plus shipping which is about $6.00. Its got about 5000 miles on it. Its drilled for a spring should you ever want more than 8# and the mounting holes are slotted for easy installation. The bolts that hold it on are a bitch to get out. Don’t know where the spring is. Cost me $93 plus tax an a weeks wait. jud Quote Link to comment Share on other sites More sharing options...
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