Not necessarily the tcv, however you definitely have a charged air leak. Does it idle rough, or stumble at all?

 

The car idles perfect but it does have the odd stumble where the idle suddenly drops then returns. This doesn't happen often.

 

So what are bad TCV symptoms then? I find my car has become sluggish (like V6 SUV sluggish) and I rarely can get boost above 9 psi even with the foot on the floor in 2nd or 3rd. Seems to rev a bit more slowly under load as well, which makes sense if power is down.

 

I should have realized this immediately, the dump valve noise means your leak is past the turbo. Could be something as simple as a radiator coupling that is unseated. You have a hard plastic charged air pipe that goes over the engine, that plastic goes to a rubber coupling to the radiator. Every connection point after that is a suspect. You are getting a blow off noise sometimes and a whistling which indicates there is an active gap somewhere in the charged air system. That whistling is your boost air escaping but since you don't have a consistent blow off noise or rough stumble it shouldn't be your tcv at all.

check the radiator air pips and the throttle body connection as well. By check I mean remove them reset them where they should be and crank it down. Don't bust your bolts but remember you have boost so don't let couplings back off things. I cleaned my over engine pipe and didn't tighten it enough and the moment boost hit they whole thing blew off immediately. I've also had the connection to my throttle body walk back until there was a whistling noise under boost and a blow off valve noise every time I let off.

Check those I would place a safe bet that you will find something and fix with a flat head screwdriver and you'll have boost again.

 

Thanks for the replies.

I will check the points where each boost hose joins.

When driving I can hear the turbo working but the car just isn't making the same power pr mpg as when I first bought it.

 

I recently replaced my TCV due to age-related failure. it would sit and chatter after engine shutdown plus had very low boost. After TCV change, it still wasn't right and would also occasionally stumble at idle. I found my charge hose (back side) was loose. Tightened it up, cleared the fault codes and let the ECU 'learn' the characteristics of the new TCV (the IPD heavy duty TCV). It's back to running as it should. No chattering, stumble, hesitation or anything.

 

^ Change in weather, old ageing hoses and ruber, slowly loosening clamps, and not to mention the boost pressure. All of that can slowly push a coupling loose or a clamp loose. tighten everything, hell I check my clamps every so often just to make sure. IF there's ever a stumble of a feeling of no boost I Immediately check the air pipes.

 

I checked the hoses that I could see/reach and did t find any that were loose.

I also sprayed inlet cleaner around the hose joints while the car was idling to find a leak. I didnt find anything.

Does the 2.4T have a recirculating dump valve fitted that could be leaking? Where would I find it if so?

 

Does the 2.4T have a recirculating dump valve fitted that could be leaking? Where would I find it if so?

Yes, it is mounted on the turbo and they are known to fail sometimes. It's called the CBV or compressor bypass valve. It's under the plate with 3 screws on it on the cold side of the turbo.

 

You won't see anything if there is a leak with the engine running at idle as everything is under vacuum. It sounds like you definitely have a leak somewhere. You need to do a proper leak check while your have positive pressure in the charge air tubes.

If you can't do that then I would suggest removing the rubber charge air tubes and inspecting them for rips/tears/splits.


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Thoroughly inspect all the air connections that have pressurized boost air. It's going to be something from the turbo to the manifold.

 

Thanks for the replies.

One day on the way home from work I had a dump/blow off valve sound every time I let off the gas after hard acceleration.

This hasn't happened since but I was thinking this could of been caused by the compressor bypass valve.

I will remove all the soft rubber hoses to get a better look at them for cracks.

 

Just wanted to update this.

I removed the rubber intercooler to turbo and the hard cross over pipes. I intended to check the CPV for rips/tears.

I got two of the CPV cover bolts off then ran out of time. The third seemed impossible to reach. (Any advice for this?)

I put it all back together and now the car seems to have power again when accelerating.

I am guessing it had a leak from one of the charge pipe joins.

 

^I'll be doing this just before my road trip to palm springs next week as well as replacing the 3 vacuum lines to the tcv and the tcv itself. Any advice on removing the heat shield and on adjusting the waste-gate? I want the car to boost just a bit earlier and to have a tad more responsive throttle.

 

Limber up. It's a pain to access the bolts. You might be able to hand adjust the wastegate rod without removing the shield but probably not.

 

You can reach the heat shield by leaning over the engine from the passenger side.
- Remove the stabilizer bar.
- Remove the 3 10mm bolts from the heat shield using a ratchet wrench and push it to the side.
-Remove the pin that hold the actuator arm on the waste gate.
- Loosen the counter hold nut on the actuator arm and tighten a 1/2 at a time and test drive until you reach your desired level.
IPD has a good video on the adjustment.

If working on the CBV.

- Remove the stabilizer bar
- Remove the charge air pipe.
- Remove the turbo intake pipe.
- Plug all the opening on the turbo with paper towel
- You'll have to straddle the engine to get down to the CBV.
- Use a 10mm ratchet wrench and remove the two top bolt on the cbv.
- Rotate the unit to the side to gain better access to the bottom bolt and remove.

It is a bear to do so much patience is required. I strongly suggest a ratchet wrench and a magnetic wand to retrieve any dropped bolts. During install do not over tighten the bolts as if they snap off you're boned and will need to remove the turbo to work out the stud.

 

Folks,
Followup if I may (post #7 in this thread)?... I have a problem nobody seems to want to help resolve (even with me paying for it)

Car has been perfect post TCV changeout & adaptation. Power (low end boost) and Econ (26-27 mpg highway stable 93 octane gasoline) all per normal operation.

6 weeks ago, car went to dealership for maintenance (alignment and simple checks). Upon exit, no boost, no fuel economy.
Took car to other dealership in town after call to VCNA. Results: Tire balance improperly done; alignment improperly done.. had bend in trailing suspension arm due FOD strike.. very visible by tech.

Dealership checked entire vehicle and test drove. They conclude boost low/non-existent but find no faults/leaks.
I've driven over 1000 miles attempting to retrain. Unable to 'retrain' the system. Engine performance (as if natural) starts gaining strenght at 2500-2700 rpm, reaching maximum around 3000-3500 then plateaus.
Gas mileage in the toilet. 5-10 mpg around town (previous 18-20), highway 15-18 mpg at stable cruise 65 mph level terrain.

I have since learned (been educated by the tech) all adaptations were purged/cleared, which describes what i experienced immediately upon leaving first dealership (one's who caused

Today I performed a complete adaptation reset/clear and immediately took the car out on the limited access highway (interstate). Set the cruise. Drove 180 miles out and returned (360 rt)
Fuel gauge shows approx 1/3 tank remaining. D.I.M. calculations with odo reading indicate ~450 miles full tank range (compared with 475-480). D.I.M mpg display indicates 22 mpg which doesn't match it's range calculations & trip odo.

Boost non-existent (or VERY low) until ~2500 rpm as before. I *think* i felt a flutter around 3800 rpm under 3rd gear load. power 'dropped' suddenly and only momentarily, then immediately returned.
Engine starts and idles fine but a ) very low-throaty, almost gargly exhaust note, frequently smell 'hot exhaust' after vehicle shutdown. These are not normal.

Question: Given VIDA can be forced to overwrite and the dealership in question refuses to admit any mistakes might have occurred, could the wrong maps been loaded but is being denied because they don't want to 'own the problem'?
-or- could a simple set if mistakes (which I think is the case) really dorked up the maps, hence wiping all the previous adaptation files?

My other option as I see to this point: Check CBV when I pull the manifold (have a minor exhaust leak when cold), replacing if needed with IPD. Give the actuator arm 1/2 or a full turn while turbo is off to compensate for 'new norm' on the low end.


Thoughts and suggestions?
Thanks,
C

 

It really sounds like they left something unplugged or put a hose on wrong or something. I'd check everything related to the boost starting with the wastegate and TCV hoses and electrical connections. But if the car is not running right you should definitely see a code.

Also as far as I know VIDA can't be forced to overwrite. It loads software based on the VIN it reads out of the ECU, it will not allow you to load alternate software. That's why it's so hard to do manual swaps on these cars, you can't even tell it that you changed the transmission, it only loads software for what they built the car with. So it's very doubtful that the wrong software got loaded. It's going to be a hardware problem. There's a hose missing or a sensor unplugged but it's a mystery why there is no code.

That said if it ran fine and then they messed with it and it didn't run fine after I'd be raising hell until that shop either fixed it right or paid me for the car.

Your hot exhaust and changed exhaust note might be clues that the catalytic converter is clogged. That can happen at any time, the core is ceramic and it basically breaks up into chunks and blocks off exhaust flow. Try to tap on it or shake it and if you hear any thing resembling rattling you should probably replace it.