97 V70r turbo/boost issue

[Muzzleflash]

Symptom: - Stage 1 remap that boosted well to around max 13psi. Over the last couple of days, it's started boosting to around 6psi only and a fairly audible whooshing/rush of air noise is heard on deceleration. It never did that before and it doesn't do it on acceleration, oddly. The car is fitted with an analogue boost gauge, connected to the vac tree.

I have replaced and done: A vac smoke test and replaced all perished hoses. I have fitted a new OEM Pierburg TCV and a Forge Motorsport Diverter/recirc valve.

I will be checking my wastegate arm/movement tomorrow as a next step. Any pointers appreciated.

[Dangerous Dave]

You're on the right track, check all the hoses, wastegate, etc.

Things to watch out for are breaks in hoses that are hidden, once had a tear in the hose from the intercooler to the throttle body but it was around the back of the pipe and wasn't at all obvious even when pressurising the system with a compressor (could hear it but not see it).

And check the intercooler isn't leaking as the plastic tank ends can break.

Also there is a couple of check valves that form part of the emissions system, one comes off the front of the manifold under the vac tree and is 8mm piping, the other comes off the same pipework and connects onto the turbo inlet by the pcv valve. The flap inside the check valves disintegrates and lets the boost out.

[Muzzleflash]

Also there is a couple of check valves that form part of the emissions system, one comes off the front of the manifold under the vac tree and is 8mm piping, the other comes off the same pipework and connects onto the turbo inlet by the pcv valve. The flap inside the check valves disintegrates and lets the boost out.

Now this got my antenae tuned, as it's basically the last vac pipe I need to replace. The garage smoke test highlighted two tiny pin holes in other pipes, which were rapidly replaced - but as it didn't cure the problem I decided to replace the rest myself. Where are those plastic check Valves available from??

[MoleT-5R]

Just in case you don't already know, but when checking the intercooler you will/should find a small leak as the std intercooler has a small drain hole in it, but as Dave has said the end caps can crack and leak after time.

[Muzzleflash]

I disconnected one of those plastic check Valves and blew into it. It will take air either way, so presumably it's fecked. Was going to replace with aluminium ones, but the OEM versions have 8mm outlet and 11mm inlet. Very odd, but very difficult to get so it seems. I guess Ovlov only??
https://s22.postimg.cc/hw2qwv2e9/DSC_0181.jpg (https://postimg.cc/image/ozamch7tp/)

[MoleT-5R]

That could be the answer to your problem then, they are available from volvo and do cost a bit for a plastic valve, order from FRF Swansea and you should be able to get them for a sensible price using the discount code, which for the life of me I can't remember, search it here or someone will probably be kind enough to post it here on this thread. Hope this solves your boost issue.

[Muzzleflash]

That could be the answer to your problem then, they are available from volvo and do cost a bit for a plastic valve, order from FRF Swansea and you should be able to get them for a sensible price using the discount code, which for the life of me I can't remember, search it here or someone will probably be kind enough to post it here on this thread. Hope this solves your boost issue.

Thanks - somebody over on the Facebook forums said he tried to get them from Volvo recently but they are now discontinued. No matter, I have ordered some 10mm ally ones off Fleabay cheap and will give those a go before attempting to source something better (if)

Reckon I should be able to stretch 8mm vac pipe over a 10mm nipple...

[Dangerous Dave]

I disconnected one of those plastic check Valves and blew into it. It will take air either way, so presumably it's fecked. Was going to replace with aluminium ones, but the OEM versions have 8mm outlet and 11mm inlet. Very odd, but very difficult to get so it seems. I guess Ovlov only??

That would probably be it :)

I did try to get some from Volvo some years ago and just for one check valve it was £49.


Thanks - somebody over on the Facebook forums said he tried to get them from Volvo recently but they are now discontinued. No matter, I have ordered some 10mm ally ones off Fleabay cheap and will give those a go before attempting to source something better (if)

Reckon I should be able to stretch 8mm vac pipe over a 10mm nipple...

I got some 8mm inlet/outlet aluminium fuel check valves off ebay for about £3 each and bought some 8mm black silicon hose as the original stuff was perished anyway. Then stretched the 8mm hose onto the T piece after the valve, has been fine for the last 8 years.

Fingers crossed this is the problem :D

[Muzzleflash]

I got some 8mm inlet/outlet aluminium fuel check valves off ebay for about £3 each and bought some 8mm black silicon hose as the original stuff was perished anyway. Then stretched the 8mm hose onto the T piece after the valve, has been fine for the last 8 years.
:D

Thats exactly what I plan to do - except I bought 10mm valves and both 8 & 10mm vac hose
We shall see..

[Dangerous Dave]

Should be fine :)

[MoleT-5R]

Had mine a year our so ago for the 850 with no problems, just need a good parts dept, frf should be able to source these valves at a sensible price, as like Dave I paid a premium from volvo for these.. :(

[Muzzleflash]

To be honest, im not convinced replacing these will solve the issue - hence for now Ill buy cheap ones and hope for the best! I mean how and why would these cause a fairly audible 'whoosh' on decelerating?? ��

[MoleT-5R]

Just a thought if you still run the original by-pass valve on the turbo, check if the diaphragm is not split or broken, that could possibly give the whoosh you mention and would also cause a loss of boost.

[Muzzleflash]

Just a thought if you still run the original by-pass valve on the turbo, check if the diaphragm is not split or broken, that could possibly give the whoosh you mention and would also cause a loss of boost.

I replaced it less than a week ago with a Forge Motorsport one. Didn't make any difference, unless I fitted it wrong?? ��

Edited to add: This one :- https://www.forgemotorsport.co.uk/Recirculation_Valve_for_Renault_Volvo_Hyundai_and_ Kia--product--787.html

[Muzzleflash]

I also meant to ask what vac readings (in/hg) people are getting with a known good system on tickover??

[Dangerous Dave]

I usually get around 19in/hg at idle

[Muzzleflash]

I usually get around 19in/hg at idle

I'm getting between 20-23 in/hg dependant upon engine temp (no frills analogue vac/boost gauge).

Those NRV's have only just turned up in the post and I won't have time to fit them until middle of next week.

Am also going to pull my wastegate line off the actuator and tenatatively see what boost I get then.... ��

[Dangerous Dave]

Just been out and mine was reading 21in/hg at idle on a hot engine

[Muzzleflash]

Just been out and mine was reading 21in/hg at idle on a hot engine

So I'm getting that, even with the knackered valves. Hmmm..

[Dangerous Dave]

Don't forget the one way valves allow flow into the manifold when under vacuum so the reading would be the same even with dodgy valves.

[Muzzleflash]

Don't forget the one way valves allow flow into the manifold when under vacuum so the reading would be the same even with dodgy valves.

I've no idea the state of the valve closest to the turbo as I didn't check it. Am fitting them Wednesday, so will report back then. Cheers!

[Dangerous Dave]

Guess what.....

I've just had the exact same problem with my car.

Loud whoosh noise when boost comes in and 21in/hg at idle without any idling issues. It started as a quiet whoosh yesterday and by today it was quite loud with a large drop in boost pressure.

So when the rain stopped I dashed out to find the problem.

I removed the air filter box completely (by undoing the pipe from the MAF) and blew into the intake pipe sealing my face around it to create a little flow. I could hear the air escaping, so I felt along the intake rubber piping starting at the top of the turbo. And that is where the problem was.

The top turbo hose had split.
https://i.imgur.com/WtYxArFl.jpg
https://i.imgur.com/DBj6yzZl.jpg

Fortunately I had a bit of spare hose, so problem diagnosed and sorted within 10 minutes.

If you haven't pressure tested yet then it maybe worth trying. Doesn't have to be an elaborate pressure testing kit, just blowing into it will work. Chances are yours is probably something similar if it is a loud whooshing noise.

[Muzzleflash]

Guess what.....

I've just had the exact same problem with my car.

Loud whoosh noise when boost comes in and 21in/hg at idle without any idling issues. It started as a quiet whoosh yesterday and by today it was quite loud with a large drop in boost pressure.

So when the rain stopped I dashed out to find the problem.

I removed the air filter box completely (by undoing the pipe from the MAF) and blew into the intake pipe sealing my face around it to create a little flow. I could hear the air escaping, so I felt along the intake rubber piping starting at the top of the turbo. And that is where the problem was.

The top turbo hose had split.
https://i.imgur.com/WtYxArFl.jpg
https://i.imgur.com/DBj6yzZl.jpg

Fortunately I had a bit of spare hose, so problem diagnosed and sorted within 10 minutes.

If you haven't pressure tested yet then it maybe worth trying. Doesn't have to be an elaborate pressure testing kit, just blowing into it will work. Chances are yours is probably something similar if it is a loud whooshing noise.

Hi mate - I've purchased a complete D088 replacement Turbo hose kit for fitment and am fitting it this afternoon along with the NRV's. Fingers, legs, toes amd everything else crossed.... ��

[Muzzleflash]

Hi mate - I've purchased a complete D088 replacement Turbo hose kit for fitment and am fitting it this afternoon along with the NRV's. Fingers, legs, toes amd everything else crossed.... ��

.....and SORTED!! Mine was a split throttle body hose, where the idle control branches off - massive split, not visible from the topside!!

One of the NRV's was shot, but the other was ok, though I obviously replaced both.

It now boosts to max 16psi (unbelieivable). Many thanks for all the help anyway!!

Stuart.

[Dangerous Dave]

Nice one!

That's where another lad on here had one split, must be a weak point then.

Enjoy :D :D

[Muzzleflash]

it's all good, except I'm still getting the dreaded 0172 code which was something I didn't elaborate on for this thread. I'm suspecting it's possibly the infamous elbow on the inlet manifold adjacent to the P|S pump. It can't be much else as I've replaced the MAF, both 02 sensors, all the vac lines and hoses except the elbow (which itself was replaced in 2012 as part of a PCV system change). It will only throw the code usually when the engine is cold. If you then clear the code and disconnect the battery for 5 mins with engine up to temp the code won't reappear until the next time the engine is run from cold. When the code appears, it limits boost to around 10psi (before it was 6-7psi, before the split throttle body hose was replaced).

Spraying around the vac elbow with carb cleaner/silicone spray does not make any difference with the engine running and I'd have thought a split one would make the engine hunt or idle quicker when something is sprayed near it!??! I do have a slight exhaust leak on the turbo manifold where I fitted a 3" downpipe, but the code was appearing well before that was fitted anyway.

[Muzzleflash]

Well I finally sorted the 0172 after months of complacency and assumption (the Mother of all feck ups of course)...

I had the local indy fit two new Lambda Sensors a good few months back and it started throwing combined 0131 & 0172 codes. I had already fitted a new Bosch MAF previously so I didn't look at that for the possible 0172 cause. I also ASSUMED that the new o2 Sensors weren't at fault, so decided to start chasing ghosts. Smoke test and all new vac/turbo pipes later cured a whole host of other bugs(as per this thread), but the 131 & 172 persisted. So, I decided - finally - to change the front o2 sensor and went to my local GSF parts place to get one.

I had asked for a Bosch and they said it would be either that or NTK, so when I went to pick it up a day later, surprise, surprise, there's a Beru sensor awaiting me. Not too happy, I accepted it and went off to fit it. On taking the old one off (fitted just a few months previous) I found it similarly to be a Beru and was a bit miffed to say the least. I decided to fit the new Beru and no surprises, similarly it threw a 131 just 5 miles of driving.

Severely pissed off, I phoned my local Euro Parts dealer (stuff GSF) and ordered a Bosch and specifically said Bosch and nothing else. I fitted it today and after a 50 mile drive no codes and all is good - better mpg, better performance and all is happy!

In conclusion: Beru Sensors it turns out (after chasing a few old threads around various car forums) have a different impedance to Bosch ones and are not fit for purpose in a Bosch system. NTK ones imo/experience are hit and miss and can work, but are not as good as Bosch. Beru though, well avoid unless you drive something French (apparently ��)....

[MoleT-5R]

Glad you've got it sorted, now you can really enjoy your Volvo.