Turbo Loss During Long Drive

[tooberand]

This last weekend I was driving along I-70 with a sustained speed of 80-85mph for 170 miles. Then when I started hitting some steep climbs, my turbo would not engage. Typically, when going up a hill (and being at 8000+ ft) just a slight increase to the accelerator and the car will downshift, kick in the turbo and accelerate easily to 10 or 15mph faster. However, once the turbo felt like it disappeared, I would have to push way down on the accelerator for the car to downshift and then there would be no turbo kicking in. There were a couple of times while having the accelerator way down that the turbo would kick briefly and get me back up to speed, but it was mostly nonexistent for the last hour of my drive. This is the second time this has happened to me. The first time was a year ago on the same drive and I didn't have any problems with the turbo for the year afterwards.

Is this behavior typical for turbos or is this symptomatic of something that may be old or going bad?

My car has 104k miles on it.

[Antherzoll]

Could be the BCS(TCV).

https://www.fcpeuro.com/products/vol...valve-30670448

Or a leak.

How is power from a dead stop?

Could also get it scanned to see if there are any pending faults. The computer in this vehicle monitors and controls turbo pressure, if the computer notices an issue it will usually set a code.

[VolvoXC70NO]

Agreed. This was the TCV on mine at least. Same symptom. Could downshift twice in uphill, still keeping same speed and just an increase in rpm. Also if trying hard acceleration from standstill it would overboost and misfire, engine control light blink (but of course stop after letting off the throttle). The original Volvo part is the best, that performance TCV isn't any better (Antherzoll has found a good one). Buy a new one, don't bother trying to buy a used one, you won't know if there's something wrong with it..

Another hint was that during cold start the TCV part would be noisy when idling. Sounds almost like an air compressor (not turbo sound).

[Reverend]

Another hint was that during cold start the TCV part would be noisy when idling. Sounds almost like an air compressor (not turbo sound).

Oooh? Interesting. My boost is rock solid. I get about 9psi when I romp on it and "normal" use of the turbo gets about 5-6psi. It also holds it nice and solid as long as I keep the foot planted.
From that, I gather my TCV is in good shape, but I do get a slight turbine whine under the hood for the first 30 seconds when it's cold and I get on the gas a bit to get out of my driveway. Nowhere near boost, so that's not it. Vacuum going through the TCV or whatnot can cause that sound?

I wasn't worried about it, but I was curious.

[VolvoXC70NO]

Oooh? Interesting. My boost is rock solid. I get about 9psi when I romp on it and "normal" use of the turbo gets about 5-6psi. It also holds it nice and solid as long as I keep the foot planted.
From that, I gather my TCV is in good shape, but I do get a slight turbine whine under the hood for the first 30 seconds when it's cold and I get on the gas a bit to get out of my driveway. Nowhere near boost, so that's not it. Vacuum going through the TCV or whatnot can cause that sound?

I wasn't worried about it, but I was curious.

Sounds like the TCV should be fine then I have the same whine on mine with a new TCV. I'm not sure why it's like that. But that sound was the same both with and without a faulty TCV. I forgot to mention that you gotta have the car hood open in order to hear that sound from the faulty TCV.

[alcraig]

Where is the TCV located? Is it a simple replacement?

Al

[Antherzoll]

Vacuum going through the TCV or whatnot can cause that sound?

I wasn't worried about it, but I was curious.

I get the same sound on cold starts, but much much louder due to the open air element and the billet compressor wheel. What's happening is when the turbo and engine oil is cold the turbo bearing has some resistance. On cold starts, air that is drawn into the engine, and exhaust being pushed out, has push against the turbo's wheels, once the engine is up to operating temp the turbo spins freely so you don't hear the sound (the turbo produces this same sound at normal operating temps when in boost). This is why you should always wait until the vehicle is up to operating temp before romping on it.

[Antherzoll]

Where is the TCV located? Is it a simple replacement?

Al

Google is your friend here. Super easy. Side of the air box, 3 hoses, and one electrical connector. Hoses may be brittle so inspect them before replacement.

[Astro14]

I would argue that you should wait until the oil is up to temp before you romp on it....oil temp lags engine temp by several minutes in normal driving...

[tooberand]

Thank you all for the advice. I'm taking my car in Friday for the 105k service. I'll get a price on TCV replacement and see if it's covered by the "Never Pay Again" warranty. If it isn't, I may get the part and tackle the job myself.