I was fine tuning my 18psi MAP for Hybrid’s dyno day coming up. Everything was working fine, I was getting the TurboXS boost controller set at 18psi. While I was messing around with it I was doing some highway pulls to get it set at 18psi. When I got back on the highway and did a pull the boost gauge showed it pulling until 15psi, then it dropped to 10psi. I got back off the highwas thinking that a vacuum line came off. I double checked everything and it seemed to be fine. I adjusted the boost controller back down some but it did not help at all. The turbo will spool fine, but it will build slow to about 8-9psi. What’s strange is the blow off valve is also not working. Normally when the turbo starts to spool and I let off the gas, there is a flutter, but nothing. I rechecked the vacuum lines and looked around the engine bay real quick and everything seemed ok. Thoughts?
I did some more investigative work into my problem. First thing I did was check and redo some of the vacuum lines off of the manifold. I moved the blow off valve vacuum from the brake booster line off of the main intake manifold line. Took it for a drive, and now only boost until 5psi. I played around with the TurboXS boost controller and even took it off to run stirctly off the wastegate, nothing. I untightened and retightened all hose clamps to make sure everything was good, nothing. It’s weird, the engine will run perfectly fine, if the head was warped of lifting, it would run like shit, if there was a hole in the block, it wouldnt run at all. If I had a bad piston ring, that would not cause a no boost issue.
I checked the b.o.v again, when the screw is tightened down completly, the b.o.v will not open at all. I believe I have narrowed it down to the external wastegate. But from my understanding, a wastegate can only be open or closed. The turbo will take a good long time to spool now, so I’m thinking it’s stuck at some point. There is alittle bit of a loose fitting from the wastegate to the dump pipe, but that wouldn’t cause anything. I’m going to take it down to Jeff in the following weeks so he can get a better look at it.