2010 XC90 Auto - loss of acceleration at higher speeds

[cheshired5]

Hi Nial,
Due to the Bank Holiday, your Dice unit will be with you on Wednesday and once setup, your first job will be to get the MAP reading with engine off ignition on and it should be around 14.5/6 psi or 100kpa (kilopascal) then the reading at idle and at 1,2,3,4k revs

You should do the same with your MAF.

I have a feeling these will give us a huge clue to where your problem lies so don't spend any more with the garage for now.

[NialStewart]

Originally Posted by cheshired5

Hi Nial,
Due to the Bank Holiday, your Dice unit will be with you on Wednesday and once setup, your first job will be to get the MAP reading with engine off ignition on and it should be around 14.5/6 psi or 100kpa (kilopascal) then the reading at idle and at 1,2,3,4k revs

You should do the same with your MAF.

I have a feeling these will give us a huge clue to where your problem lies so don't spend any more with the garage for now.

Brilliant, thanks for the feedback Simon.

My wife's booked it in for next Tuesday, hopefully I'll be able to tell them what's wrong by then!


Nial

[NialStewart]

Greg,

I still can't reply to PMs, I've asked my post count to be bumped up but no response yet.

The VIN is YV1CZ71461581312

Though I should get the Vida/Dice from Simon (Cheshired5) today so will
hopefully be able to investigate.

I would be good to have your feedback though as I'm not sure how to install the software on a virtual machine in a laptop that has no DVD drive and which I can't get the local networking going!

I think I can download something that will create an ISO image of the install disk and do it that way, but just in case.....

Nial.

[gmonag]

I have my laptop setup to dual boot. So I can run Win10 or Win7 Pro as required. That gets around any networking or performance issues with a VM.

I think you have missed a digit in your VIN

Greg

[NialStewart]

Originally Posted by gmonag

I think you have missed a digit in your VIN

Yep.

YV1CZ7146B1581312


Nial

[NialStewart]

Originally Posted by cheshired5

Hi Nial,
Due to the Bank Holiday, your Dice unit will be with you on Wednesday and once setup, your first job will be to get the MAP reading with engine off ignition on and it should be around 14.5/6 psi or 100kpa (kilopascal) then the reading at idle and at 1,2,3,4k revs
You should do the same with your MAF.
I have a feeling these will give us a huge clue to where your problem lies so don't spend any more with the garage for now.

Simon, after a lot of mucking about I have this working and have managed ot get the readings.

'MAF', is this manifold air temperature, I'd expected this to be air flow but I think the temperature was labelled as
MAF.

Readings taken with gearbox in park.

Speed.........MAP.......MAF
Engine off ...1002......41 Deg C
1K..............1018......44 Deg C
2K..............1127......41 Deg C
3K..............1221......38 Deg C

If the 4K reading would help I'll do it tomorrow, I didn't want to annoy the neighbours too much.

Thanks for any feedback,

Nial.

[NialStewart]

I've managed a log file of some values while drivign up a long hill.

The power died right at the start of the hill, you can see that the car speed tops out at about 46Mph, that was with my foot to the board.

Up to the point where I booted it and lost the power it had been behaving OK.

At the top of the hill there was a lot of wastegate noise as I rolled into a roundabout then more wastegagte noise every time the box changed gear
as I gently accelerated out of it.

Any thoughts would be greatly appreciated.

Nial.

[gmonag]

It looks to me like you have overboost issues. This will put the car into Limp Mode, which is what you describe as the symptom.

My guess is sticky turbo inlet vanes or bad actuator or failed MAP sensor. Look at the freeze frames when the codes were set.

Greg

[Keithbelson]

Originally Posted by NialStewart

We have had this car since new, always dealer serviced.

A week or so ago we started getting a problem where we'd lose all acceleration at high speed (>40mph) if you put your foot down.

If you tickle the throttle you can build up speed, but if you boot it the revs and speed don't increase, and the gearbox doesn't change up.

From a standstill if you accelerate hard the engine revs fully in first then you get the problem in higher gears, so the engine is able to rev fully.

I think I've heard the turbo blowoff valve at low speeds but am not sure.

The swirl control rod's been broken for the last X years and I reluctantly let the Volvo dealership 'fix' it on Monday, they assured my wife this would sort things out, but the problem is back today.

I've had a good search but can't find any threads that descrive this problem.

Any thoughts?

Thanks for any input,

Nial.

I have a similar problem with my V70 manual gears. Only seems to happen on dual carriageway or motorway when the sped is up. The car is proceeding nicely then when I try to accelerate there is no power and the car starts to slow gradually. If I change the gear down the power gradually comes back. This only happens occasionally. Not sure why and haven't taken the car to my garage because Sod's law it wouldn't happen when they tried it. Someone said it may be the auto throttle control? Any ideas?

[NialStewart]

Originally Posted by gmonag

It looks to me like you have overboost issues. This will put the car into Limp Mode, which is what you describe as the symptom.

When the ECU goes into Limp Home Mode does it display anything? We're not seeing anything much of the time
when this happens.

My guess is sticky turbo inlet vanes or bad actuator or failed MAP sensor. Look at the freeze frames when the codes were set.
Greg

I had a look at this and have attached two screen grabs ... Pressure_to_high_1 and _2.

I noticed that the Throttle Valve position on the three DTCs logged is 0% which seemed odd so I did a quick
log sitting idling and slowly depressing the throttle which doesn't look right.

I presume this is goosed, could this be causing the problems we're seeing?

Thanks again for any feedback,

Nial.