Hey everyone, I was helping my friend try to fix his turbo'ed 420a, because it stopped boosting. We checked all his clamps on his piping and they are all tight. He replaced the pcv stuff today and that didn't cure it. Basically, we took a test drive last night and his gauge, when he revs it, zeros out and as his revs get higher up (5,000 and up) the gauge begins to read 3-4 vacuum. When its under a load, he can get to maybe 1 psi of boost, but thats it. I'm going to try to do more searching on here, but I haven't found anything yet so that's why I posted. Anybody have any ideas?

Check the wastegate maybe it lost the pin that holds it and it stays open.

What's up, I'm the guy with the problem. I don't have a cotter pin going through to hold the actuator arm on, but I do have an e-clip.

I bought the new PCV valve today, and before I put it on I tried blowing through it, and I could. It wasn't as easy to blow through as my original one, but I could still do it. I guess that is still the problem? B/c if I can blow through it doesn't that just mean that the pressurized air in the intake is escaping out there? Later I'm going to cap off the nipple on the intake and see if I build boost then or not.

How is it possible to register vaccum with the throttle open?

It's not the PCV. Even if you had no valve there at all you'd still make boost.

Check your turbo, and recheck your piping. Check your BOV. Make a boost leak tester (search before you ask what it is) and use it.

I do get some boost, 1-2 psi.

Originally posted by DarkOne
It's not the PCV. Even if you had no valve there at all you'd still make boost. Check your turbo, and recheck your piping. Check your BOV. Make a boost leak tester (search before you ask what it is) and use it.

What should I check in the turbo? There is alittle shaft play, but the fins were still good.

make yourself a boost leak tester like D said!