Engine: D5: Intermittent boost problem seems to have become permanent!

[BenPS]

Hi all,

I've just joined in the hope someone could shed some light for me - I've found a few ideas here but I'm hoping if I spell it all out in one post I might get the answer.

I have a 2005 S60 D5 (185), with 74,000 miles. Over the past three weeks I've lost the turbo four or five times after hard acceleration, albeit briefly, but has quickly come back on again and the 'engine system service required' warning has disappeared. However, two days ago the boost went and hasn't returned except today on the motorway at around 75mph (picked up from 75 upwards quite easily). When I got down to regular speed the boost went again. Forever. Town runs and slow speeds are a nightmare.

I replaced the turbo control valve today, clipped to the side of the airbox (I think it also serves the engine mounts) but no avail, and now I'm wondering if I should change the turbo governor valve which is located nearer the engine block. All the hoses seem to be in good condition. I should also point out that it now makes an odd buzzing (almost grating) sound for 3 or 4 seconds when I switch the ignition on, or when I switch the engine off. It appears to be coming from, or below, the governor valve. Car idles fine, and drives fine except for the lack of turbo, and there's no smoke from the rear.

Has anyone any ideas before I need to take it to Volvo to get diagnostics read and/or a hole burnt in my wallet with fixes that don't solve the problem?

Thanks for any help in advance,

Ben

[Unreal master tech]

If you think it's the mounts just blank them off at the t piece I would not have bothered replacing the valve as these rarely fail. The grating noise can you locate where it comes from? If it's from the throttle which is under the air filter it could be the cause but my guess is more likely the swirl link is broken for the swirl inlet control if you look under the engine cover towards the thermostat housing area you should be able to see if it's ok?

[BenPS]

Thanks - I'll check the engine mounts today. The grating/buzzing sound seems to be coming from the turbo governor valve on the top of the engine, or just below it but I can't work out exactly where. I thought it may be the solenoid malfunctioning. If I disconnect the valve from the hoses and it still makes this noise, am I right in thinking the valve cannot be the problem? Could possibly be coming from the vacuum pump. The swirl arm looks hunky dory too.

[Lancee]

There is a throttle assembly on these, I think the gears strip, do a search on the forum, I am busy now, may post more on it tonight.

Search for "electronic throttle body".

[BenPS]

Thanks for the info, although this morning at about 70 I put my foot down and the turbo kicked in as it should, but when I brought the speed below 70 I lost all boost again. Why would it run at high speed only, and even then only when it feels like it?

[Lancee]

IMHO I think you need to get the (DTC) fault codes read to give everyone including yourself a better idea of where to look for the fault, a lot of time and money can be wasted barking up the wrong tree, and a Volvo can be like a forest on wheels.
You appear to have already spent time and money on parts which may have been unneccessary, resources which could have possibly been directed elsewhere.

[BenPS]

Just the £40 valve on the airbox so far but I'll get the diagnostics read next week.

[BenPS]

Update - Engine mounts seem fine, and I'm thinking the racket is coming from the throttle body.

[kevin100]

I have the same intermittant boost problem on my V40 (2000)
Occasionally lose about 30% of power then it comes back - on/off/on/off.
Possibbly the same, brief, metal grindy sound. Like all the oil has gone, but then its fine - yeah also mainly at high revs. Mixed with short burts of thick black smoke

I've also found somewhere is spitting out blackness,

Let me know what happens for you mate !!

[BenPS]

Originally Posted by kevin100

I have the same intermittant boost problem on my V40 (2000)
Occasionally lose about 30% of power then it comes back - on/off/on/off.
Possibbly the same, brief, metal grindy sound. Like all the oil has gone, but then its fine - yeah also mainly at high revs. Mixed with short burts of thick black smoke

I've also found somewhere is spitting out blackness,

Let me know what happens for you mate !!

Hi,

I had no smoke and no hunting so outwardly the car looked good. I was sure the noise was coming from the Throttle Body, so took it to Ron Sealey in Fife for diagnosis. Laptop confirmed it so now I'm just waiting for him to get back with some prices.