high miles 2011 xc90 3.2L rich/lean

[Vova585]

It is your money, but i would still recommend to find reputable shop/mobile mechanic who is able to diagnose your car with the help of scope. You can spend another $150 on knock sensors and still have the same problem. Rather pay for proper diagnostic and avoid "parts cannon". 2 channel scope with in-cylinder transducer and reference point at ignition coil would be necessary to do proper wave form which will tell you which system is at fault.

[ikeever]

You are correct. Volvo appointment is made they’re gunna charge me 300 anyway to diagnose. Aftermarket knocks are 15$… parts cannon, I like that

[Vova585]

Try to find local junk yard or buy used oem version of knocks if you are willing to try to replace them at this time. Aftermarket electronics are notorious to create more problems than you had prior. If you made appointment with volvo dealer ask them what tests they did to diagnose your car and ask for copy of results(it is your data for which you paid). Or look around if there is a shop nearby that has good 2-4 channel scope and mechanic able to interpret waveforms. The shop that i sent prior is highly reputable in around FL area, but not sure how far you are from it.

[ikeever]

Aftermarket parts get a bad wrap, they’re so cheap you can use them for troubleshooting! Then replace with the good stuff. I’ve had decent luck with them.

[Vova585]

Do as you wish. It is your car, your money, your time. From what i see-you are not able to pinpoint the problem and willing to start throwing parts at this car in hopes that something will fix the issue. At the same time you are not willing to put quality used or OE/OEM parts into this "parts cannon" so you might create more problems than good. In case you will bring this car with plenty of new aftermarket sensors to a shop, they will spend more time(which will be charged) or will refuse to work on it all together. You need professional help with advanced level diagnostic to quickly find what is wrong. It cost money, but likely will not be more than $250

[ikeever]

My strategy or aftermarket parts and fomoco parts has gotten a 3.2L to 278k miles, so I’m happy with my strategy. If you try and get that many miles on a xc90 with dealer and OEM parts, you would have more money in the car than it’s worth. Remember this things worth about 3k on a good day….

[abscate]

Can anyone with 100% certainty say the downstream O2 sensors have no effect whatsoever on DME fueling and trims? I’m not an expert on the code. I think they only monitor cat health and nothing more…

DENSO downstream sensors on some p2 platforms do influence fuel trim , current thread in the p2 v70 forum. It’s like they do in xc90 too as that’s built on the p2 platform

[ikeever]

Hmm ok than maybe I should change downstream o2 sensors before I send to deal. Two new camshaft sensor did not correct trim problem

[ikeever]

Can anyone with 100% certainty say the downstream O2 sensors have no effect whatsoever on DME fueling and trims? I’m not an expert on the code. I think they only monitor cat health and nothing more…

DENSO downstream sensors on some p2 platforms do influence fuel trim , current thread in the p2 v70 forum. It’s like they do in xc90 too as that’s built on the p2 platform

can you point me to that topic?

[ikeever]

Nevermind I found it