EGR & Lambda DTCs

[A lex]

Hi Diro,

Indeed you did mention those things earlier and looks like you are correct.

I think its almost certain I will need the IC replacing tomorrow, but I will wait and see what the morning brings.

Thanks for the links with the resonator pipes - I wont be able to order them in time, but I will mention the gaskets to the mechanic and probably order these parts to fit myself when I am back from holiday in France.

Although it is v. annoying to have such a problem with only 135k km, its much better for it to be this than an ECM problem I think!

A sticking EGR is also something I will have to keep in mind. I guess the first job is to change the IC and gaskets and take it from there.

Thanks!

[A lex]

I think I can

tentatively

say

FIXED.

The IC was completely wrecked. Blown out top and bottom, but particularly on the bottom. Only 137k km on the car, so im a bit surprised.

An 'aggressive' test drive later and I cant replicate the fault. Im knocking on wood etc here, as I appreciate there could be another problem still lurking, but I hope (please!) that is it fixed.

So, some thoughts and advice for others in the future reading this.

-ECM codes for the MAF in combi with the Ho2S sensors in 'signal too low' condition can actually mean a blown IC. I never had any DTCs for boost problems. I guess the intermittent reduction in boost was upsetting the MAF and Lambda.

-I was somewhat 'pressured' in to trying my own solutions and essentially wasting some money on sensors. To be honest I dont feel too bad about it. I now have a good spare MAF, the lambda sensor ill accept as wasted money and the MAP sensor was only €40, so no worries there.

-I asked them to use a non-genuine IC when replacing; Ive gone for Nissens which is a good quality part. Reasons being:
1. Volvo part is €500+ and isnt exactly top quality. Nissens part was €250.
2. Volvo part was one day+ delivery. Nissens was there in <1hr!

-Because I have used my local indy guy to replace im looking at about €450 for the IC work, plus the €300 I spent on unneeded sensors - so im still well under what Volvo would charge me to replace the IC in their workshop.

-Also a decent example of how a little 'knowledge' gained by using VIDA can lead you up the garden path somewhat.....!


In any case, it LOOKS like its not an ECM problem, and for that I am truly grateful. €700 in comparison to €3k+ seems like a decent escape.

Also worth mentioning that the car is now driving beautifully. I suspect the IC issues have been creeping up for a while as fuel economy has been on the slide for about 3 months. Its also a lot faster again now!

Some IC pics.

[A lex]

Also worth mentioning Ive ordered the replacement (stronger) bottom hose/resonator mentioned by a poster earlier in the thread.

Will fix that myself when back from hols.

[cheshired5]

Have you managed to find out whether your boost figures are normal for a Polestar equipped car?
Even if the figure is normal, I can't help thinking that your 24 psi boost will once again make mincemeat of the new intercooler.

[A lex]

Originally Posted by cheshired5

Have you managed to find out whether your boost figures are normal for a Polestar equipped car?
Even if the figure is normal, I can't help thinking that your 24 psi boost will once again make mincemeat of the new intercooler.

Ive emailed Polestar for an answer. Im awaiting their response.

With the VNC on the turbo being electronically rather than Vacuum operated, theres not much (as far as I can see) to do in terms of fixing an o/boost situation.

The Polestar SW has been on the car since day dot and this IC made it 137k km. If this new one lasts the same its 99% likely I wont have the car anymore.

[cheshired5]

Originally Posted by A lex

Ive emailed Polestar for an answer. Im awaiting their response.

With the VNC on the turbo being electronically rather than Vacuum operated, theres not much (as far as I can see) to do in terms of fixing an o/boost situation.

The Polestar SW has been on the car since day dot and this IC made it 137k km. If this new one lasts the same its 99% likely I wont have the car anymore.

It probably won't be overboost then and is likely just "how it is" when mapped. Let us know if they reply.
The original life of 137k km will likely be reduced this time around because you're not starting from a clean engine and turbo but as long as it lasts as long as you need, no worries.

[A lex]

Originally Posted by cheshired5

It probably won't be overboost then and is likely just "how it is" when mapped. Let us know if they reply.
The original life of 137k km will likely be reduced this time around because you're not starting from a clean engine and turbo but as long as it lasts as long as you need, no worries.

Yup. Realistically it needs to last another two years and 60k KM. Id hope it would make that.

Plans are (if all goes well) to move over to a new XC90 T6 or T8 in 2017

[A lex]

Fair to say with the new IC, the performance is back:

[5cilinder]

I have the same remap and 24 psi (1,6bar) is normal ,1.3 bar is stockpressure
More performance needs more pressure for smokefree combustion
The dips in the graph are not normal ,probably a combination of rising engine rpm and ic leakage wich the turbo cant compensate for

[A lex]

Have driven >1500km this week across France (fully laden and at high speed).

No problems with the car, so hopefully can put it to bed.

Economy also back up to around 30mpg (8,9L/100 on the OBC).