2001 V70XC - struggles to idle when coming to stop light Topic is solved

[xHeart]

Yes!

Try to swap it back? :)

Also did you do a vacuum test for membranes in wastegate and in CBV? When they tear the pressure coming from turbo becomes erratic, not what ECM expects.

Old TCV is going back.
The yellow tube coming off of westgate holds vacuum. Red from CBV does not - I can also blow air into it.

[vtl]

Old TCV is going back.
The yellow tube coming off of westgate holds vacuum. Red from CBV does not - I can also blow air into it.

Red as here? viewtopic.php?t=63924

CBV is green, it is attached to inlet manifold. If you really found that the air/vacuum leaks through CBV - you have found your problem.

The data freeze looks promising for the torn CBV theory: the pressure is above typical for your engine and load, fuel trim says ECM was cutting back fuel delivery in a hope to reduce the pressure, which is not dropping, because CBV is torn.

If you going to replace the CBV with the turbo in place, it will be tricky, but doable, with a good selection of tools. Advise would be to thread in the lowest bolt first.

[xHeart]

Old TCV is going back.
The yellow tube coming off of westgate holds vacuum. Red from CBV does not - I can also blow air into it.

Red as here? viewtopic.php?t=63924

CBV is green, it is attached to inlet manifold. If you really found that the air/vacuum leaks through CBV - you have found your problem.

The data freeze looks promising for the torn CBV theory: the pressure is above typical for your engine and load, fuel trim says ECM was cutting back fuel delivery in a hope to reduce the pressure, which is not dropping, because CBV is torn.

If you going to replace the CBV with the turbo in place, it will be tricky, but doable, with a good selection of tools. Advise would be to thread in the lowest bolt first.

Hopeful! The color coded IPD hose set matches the colored dots on Pierburg TCV. So the RED is connected to nipple just below the triangle shapes fixture, Volvo Bypass Valve -- this one:



Correct, attaching Mityvac on the red line coming off of nipple below Volvo Bypass Valve 271640 does not hold vacuum. This replacement part is meanly prices.

There is also an MTC branded replacement.


The IPD website shows this repair kit above^, any good?

[vtl]

Maybe your engine vacuum system is different, but in my 2.5T the CBV is connected to inlet manifold (after throttle) and TCV is connected to turbo's cold air outlet (before throttle). Here I hold the other end of CBV hose that attaches to the manifold (not present in the engine bay ).



Anyhow, CBV should hold both the pressure and vacuum, and IPD w/ the stock-rated spring will do just fine.

[xHeart]

Maybe your engine vacuum system is different, but in my 2.5T the CBV is connected to inlet manifold (after throttle) and TCV is connected to turbo's cold air outlet (before throttle). Here I hold the other end of CBV hose that attaches to the manifold (not present in the engine bay :wink: ).

Anyhow, CBV should hold both the pressure and vacuum, and IPD w/ the stock-rated spring will do just fine.

I'm imagining taking off the metal engine bracket cover over the rear cam seal sensor to reach the bypass valve -- what hand tools, offset type?

[abscate]

14mm M8 or M10 hex bolts, but kiss them with some heat for 30 seconds first, using propane.

THose bolts are steel into Al and they like to hug their Al buddies for as long as they can.

Crack them with a 24 inch bar, lay down the Holy Water of PBB, and then zip them off.

14mmsocket, deep socket, extensions, and wobble.

[xHeart]

Maybe your engine vacuum system is different, but in my 2.5T the CBV is connected to inlet manifold (after throttle) and TCV is connected to turbo's cold air outlet (before throttle). Here I hold the other end of CBV hose that attaches to the manifold (not present in the engine bay :wink: ).



Anyhow, CBV should hold both the pressure and vacuum, and IPD w/ the stock-rated spring will do just fine.

Pulling my hair moment vtl (bewildered).

Found the green line between CBV and intake manifold, like you show in pix. Tested, and CBV holds vacuum.

[vtl]

Found the green line between CBV and intake manifold, like you show in pix. Tested, and CBV holds vacuum.

What about the wastegate? Can you do the same vacuum test?

[xHeart]

Found the green line between CBV and intake manifold, like you show in pix. Tested, and CBV holds vacuum.

What about the wastegate? Can you do the same vacuum test?

Westgate holds vacuum.

[vtl]

Westgate holds vacuum.

The last things to check are the wastegate adjustment (https://www.matthewsvolvosite.com/adjus ... wastegate/) and whether MAP sensor is faulty/lying. If everything is fine, it all points to the ETM, I think.