2001 V70T5M Less Than (Stage) Zero

[dux02v70]

Finally had the chance to dig into it a little. The hose to the CBV was cracked at the nipple so that was where the low vacuum was coming from. And most of the low boost I would imagine. I also pulled the tube running from the turbo to the intercooler and it was cracked around the mount that attaches to the top of the manifold. I cleaned it with carb cleaner, sealed it up by melting the plastic with a soldering iron, scuffed the area up with 80 grit then reinforced it with some plumber's epoxy I had (basically white JB Weld.) Now I have 20 in Hg at idle, 22 during closed throttle coast, and boost spikes to 18 psi followed by a steady 14.8 psi. Man this thing pulls hard. I'm now very concerned about the durability of my license.

By the way, I would say that a combination of low vacuum and low boost with no codes would point to a leak in the CBV line if that is where you have tapped in for the boost gauge. The vacuum/boost values indicate the condition present near the gauge so if the engine is performing fairly well otherwise the leak would likely be near the port where the gauge is connected. The vacuum readings within the manifold were probably significantly higher than the 6 in Hg I was reading which is why the engine was able to run well. I also had no issues with the brakes which I would have expected if the vacuum was truly that low.

I still haven't done the turbine pressure hose. I'll get to that this weekend. Plus I need to make my boost gauge tubing more secure. The connections popped a few times and although I found some worm-drive clamps that seem to fit I want to make it cleaner and more robust.