Why Me. Please Help Turbo Issues

[civileclipse]

I have a 95 GST, and it's been running great. No funny sounds, spooling well. All up until tonight. I was late for work and I didn't let it cool down like i usually do. I hadn't really been getting on the turbo on my way to work though, and I was mostly sitting at stop lights and what not so I didn't think it was an issue. I got out of work and gave my friend a ride and I ran it through first and second and it was spooling great, then I let off the throttle and stopped at a stop sign. I wasn't really getting on it for a few minutes next thing i know the turbo does not spool at all. I looked under my hood and my air filter was completely off of my cold air intake. So i thought well maybe thats the problem. I put it back on and tighted it down but it's still acting funny. My boost gauge shows -20 pounds when i'm off the throttle but goes only goes to 0 pounds when I hit the gas. I checked all of the hoses running from my blow off valve to my boost controller to my turbo, etc. I didn't see any leaks (although it is 11 PM and I didn't have the best source of light) I couldn't see anything right off hand. Like i said i didn't smell anything odd, the turbo looks fine there's nothing dripping out of it or smoke pouring out of my hood. I'm guessing this is likely a vacuum issue. But then again that's only a guess. Please help.

Civileclipse

 

[MrBoxx]

Anything under 0 on your boost gauge is measured in in/Hg of vacuum, not negative psi. So your "-20 pounds" should be phrased "20 in/HG vac". Just FYI.

Check that the wastegate actuator arm hasn't fallen off the wastegate flapper arm on the turbo. You may need to replace the cotter pin if that has deteriorated or fallen out. A paper clip works in a pinch.

Also, do a boost leak test.

 

[lexx620]

check for any boost leaks . start with your intercooler pipeing. some thing similar happend to me and it was because my upper intercooler pipe had come off the intercooler. If u had blown the turbo u would have seen some smoke. good luck

 

[civileclipse]

This is a newb question but is there a better way than just feeling for leaks to see if there's a boost leak?

 

[MrBoxx]

How to make a boost leak tester.

It's very simple and cheap to make. To use it, get an air tank and set it to release air at about 20 psi. Put the boost leak tester on your turbo inlet, attach the air tank hose, and start pressurizing the intake tract. Watch your aftermarket boost gauge. If there are no leaks, it will go up to 20 psi. If you stop the air supply, watch the boost gauge and see how long it takes to fall back to zero. It should hold pressure for at least 30 seconds. When the system is pressurized, you'll be able to hear leaks, but you can spray soapy water on the intake tract to help pinpoint where they are.

Did you check the wastegate actuator arm?

 

[civileclipse]

It is indeed the wastegate actuator arm.. My only problem is how to get it back on? I've been working with the arm trying to get it back onto the little peg it fits on and its really close to going back in but its a little off. I don't want to pull to hard on it and break the arm, any suggestions?

 

[MrBoxx]

It's a little stiff to move, but it'll move more than you think. Make sure that the flapper arm is as close to it as you can get it.

 

[civileclipse]

Thanks. I had it just about on, and i ran about 5 or 6 psi into the hose that runs into my actuator and it gave me an extra 1/8th on an inch to fit it on. Thank you for all of your replies.

 

[MrBoxx]

No problem. Just remember to put a cotter pin or something in the hole to keep the actuator arm on. Riding around town with 0 boost really sucks.