I just bought a Sunbird gt Turbo and the top end was apart cuz one ov the valves were toast. So i put on a rebuilt head that i had for my other bird and put it all back together. Now the car runs fine on idle and little accel. but studders under heavy accel. I suspect a vaccum. There is one that doesn't have anything plugged into it. Let me try and explain wich one.. so there are 4 lines out under the intake and those are all there, and there a rubber holder of 3 lines shortly after it. 2 of them go to hard lines but the top one doesn't go anywhere. What am I missing? If someone has a diagram for these lines, it would be great. There is also a vacuum sensor of some sort that has 1 line going to it (has a 2 pin connector with a blue rubber thing). Should it have 2? Cuz it looks pretty beat up. Please let me know ASAP, i hate driving like this. Thanks.

check to make sure there are 2 lines going to the charcoal canister. from what you are describing, this is all i can think of.

this doesnt realy sound like a vacume leak. you gotta remember that with a turbo under acceleration you are in boost, meaning positive pressure in the intake, so your vacume leak is now a boost leak. my buddies turbo bird has a bad "shudder" (seemed like a bad miss) at heavy throttle, turns out is was the pickup coil in the disributor (dont mix this up with the ignition coil). it seems that after years of wear, the pickup coil was vibrating around, basicly cauing the timing to fluctuate, im gonna guess, at least 15 degrees. this caused bad detonation. changed the distributor, it was fine.

I think you're right. I was driving it around today and i noticed that the boost guage was going right up to 100+ under high accel. and the CE light came on. So i pulled the codes and got 31, actuator trouble. Is there a way to test it? I can move the shaft with a screwdriver. Any ideas are very appreciated!

ummm, check the vacuum line that runs to the wastegate.. As far as the disconnected vacuum line that you don't know where it goes, do you not have a vaccum hose routing diagram on the underside of the hood at the front? If not I can take a pic of mine, same year and engine, and post here a little later. What shaft are you talking about moving with a screwdriver??

No i don't have that diagram. And that pic would help alot. The hood was painted and i guess it was pealed off. I checked the vacuum line and it is connected on the turbo but i can't really follow it. I am talking about the shaft that comes out of the actuator and is connected to the springloaded wastegate. All i was saying is that it didn't seem to be seased or anything.

anybody have that diagram?

Hey, sorry. I needed to take about a 50 mile trip to my grandparents house to get a pic of the sticker, which I haven't done. I think I will do that now, just for you. LOL Not really, but anyway, I will post it in a little while

Alright thanks a bunch. Whenever you get around to it just post it. I'll be keeping a look out for new posts here. But isn't there anybody else that has a sunbird turbo just take a quick look or pic of the vaccum lines, or a diagram? Thanks in advance!

I took some pics, but there was no way you would be able to understand anything from them. Tried in all kinds of light but always came out too blurry to use. Thinking about other options, maybe draw a diagram and scan it?

I've got a Chilton's book with a diagram in it, but I don't have a scanner. I'll do my best to describe them for you but I'd recommend getting the book to be sure.

All of the directions will be based on looking at the engine from the front.

There are 3 lines on the charcoal canister. The one furthest left goes back behind the valve cover and connects to the throttle body at the 3rd port from the left.

The next line to the right on the charcoal canister follows the first and goes behind the valve cover and connects to the throttle body on the left most port.

The third line on the canister goes to the fuel tank.

The boost controller is near the front of the engine just over towards the left. It has one vacuum line that connects to the boost solenoid (near the center of the engine between the intake and valve cover). The line comes out of the other side of the boost solenoid and continues to the port on the throttle body furthest to the right.

A vacuum line comes out of the left side of the intake manmanifoldd goes slightly left, T's at the fuel pressure regulator and continues on to the map sensor.

A vacuum lines goes out of the EGR valve (in front of the intake) and travels under the intake between the ports and goes to the electric vacuum regulator on the back side of the intake just right of the center of the engine. That line connects to the vacuum regulator on the port closest to the front of the engine.

The other port on the vacuum regulator (the one closer to the firewall) goes around to the right side of the intake and through a check valve on the right side of the engine bay, it then turns left and connects to the last remaining port on the throttle body. The port second from the left side. It looks like this connects under the other lines on the throttle body so It might be tricky to spot to find.

There is also a line from the pcv valve to the intake.


That's what my book shows for a 1990 turbo 2.0. I hope it make sense and helps you find your problem, let me know if you have any more questions.





You can't outrun the radio.

Thanks guys! I'm gona print those out and go have a look and see if everything is right.

Alright well i think i found the problem. The line going to the turbo was broken in half behind the timming belt plate. So i fixed it and it runs better. But i do have one question. Under mild accel the boost guage stays at half or a little bit over. But if i gun it to the floor the needle almost hits the top. Is that normal? this is my 5th bird but the first gt turbo i could find around here, so not sure whats considered normal. So anybody let me know plz! Thanks.

welcome to turbo cars. a turbo motor wont make full boost at light- mid throttle. typicaly, at mid throttle, you will have no vacume or boost. the turbo is spinning and pushing enough air to keep the motor fed, but not enough to create pressure. once you roll into the throttle harder, more exaust flow spools the turbo and you get more boost. just always remember, with a turbo, boost is not linear with throttle opening or rpm, superchargers are like that.

oh, and always keep in mind that the stock boost gauge is highly inacurate. without an aftermarket gauge, about all you can know is if the car isnt hitting fuel cut, your below 12psi.

Thanks for the info and i gotta say that i love the feel of a turbo! . And i aware that the stock boost guage isn't acurate and i have a boost guage and a manual boost controler comming in from eBay (no shops in town have these). Thanks again for the help and advise.

Glad to hear you got it running better.





You can't outrun the radio.