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Discussion Starter · #1 ·
Hello all.
I have a stock 2009 S40 T5 AWD auto that I purchased with 103k miles this past spring.
The car came from Florida and sat mostly idle for about a year before I bought it.
I did a proactive change on the plugs (Denso iridiums) and Bosch aftermarket coil packs and oil to freshen it up, and had to replace the fuel pressure sensor on the rail not long after. This was done about 10-15k miles ago.
I also have been running Mobile 1 5-20 full synth every 5k miles since I got it.
Everything has been running smoothly since the changes until the past few months.
I am now at 123k miles and the engine generally seems to be running a little rougher, both physically and audibly.
The most pronounced problem is that I am now experiencing what feels like missing and power loss during hard passing and some general acceleration.
There have been no lights of any sort to indicate problems.
After reading some of the threads here, I changed to the Volvo branded plugs (30751806), verified the gap at .026 and torqued properly.The Denso's still looked OK and the problems persisted.
I also had another oil change this past week, and the symptoms remain the same.
I will be having the timing belt changed shortly to cover the maintenance interval but it still looks good, so I suspect there is another problem.
Does anyone have any thoughts on another likely cause? Coil packs maybe again?



Thanks, Randy
 

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Have you checked/replaced the air filter? Simple, but maybe another place to look.
 

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Discussion Starter · #3 ·
Thanks for the Reply Logan. I took a quick look at the filter.
It's a little dirty, but not too bad...I replaced that around 15K miles ago as well.
To muddy the water, my mixer door for my vents is sticking a bit between high, mid and low.
I wonder if I may have a vacuum problem, or if that's just a red herring.
I'm going to have a look around my air box this weekend for loose hoses or blockage.
 

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Discussion Starter · #4 ·
It looks like I may have found the culprit.
I performed a quick PCV test with the dip stick, and noticed that the engine will bog down and idle sporadically if I block the tube off with my finger vs leaving the dip stick tube open.
I am probably at the beginnings off a PCV failure, so I will go after that first.
I've not run into this before, so feel free to let me know if I'm on the right track.


Thanks, Randy
 

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What are the current outside temps when this happened? What octane fuel? Any tuning?


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Definitely swap it. Volvo is notorious for this.


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While your at it, check all of the hoses and connection to and from.


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Discussion Starter · #8 ·
Genuine Volvo PCV and tube have been ordered and should be here on Monday.
I'm hoping I can drive it safely for another day, as I have to work.
Fingers crossed :).



Randy
 

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Just dont go throwing a lot of boost at it. Keep uour foot out of it if possible.


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Discussion Starter · #10 ·
I finally received the PCV assembly and tube, and I got it installed yesterday.
The tube was partially blocked and the diaphragm was intact but a bit stiff.
With both replaced, the engine is definitely running smoother and strangely the whistling noise that I had always associated with the turbo has diminished or gone away entirely. (I'm not historically a turbo guy so I have little frame of reference.)
Under normal driving, the engine is smooth, balanced and quiet, but as soon as I start to demand a little boost it starts to sound a but raw, harsh and throaty...more that I had seen before. This continues with heavy boost and hard acceleration and I notice a little stumble at high RPM.
Is it possible that the PCV may have caused problems in the turbo as well?
I am still due for the timing belt and I can have them look at it when I take it in, but I would sure like to know what I'm dealing with before hand if possible.
Any advice would be greatly appreciated.




Thanks, Randy
 

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PCV Whistle is a common problem. Its the diaphragm inside that gets damaged. Good to have replaced it. It could take a few drive cycles for the ECU to relearn. Drive it normally for awhile with some short distances shifting back into park for 10 seconds or so and then slowly through the gears and then accelerate normal a few times and then a few times under hard acceleration. These ECUs can be finicky, constantly trying to learn your driving habits.

As far as missing? Are there any codes? Or does it feel more like a sudden loss of power? How old are the plugs/coils?


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Discussion Starter · #12 ·
Plugs are new Volvo branded spec'd for the T5.
No codes have ever shown relating to these problems.
I will give it a day of driving and stay out of it a bit to see how it does.
 

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Could be crap fuel, was it hot out?


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Discussion Starter · #14 ·
The weather is currently temperate here in West Michigan.
The problem has been going on for a few months with several tanks of gas.
I almost always use Mobil premium which is 93 octane around here.
 

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The weather is currently temperate here in West Michigan.
The problem has been going on for a few months with several tanks of gas.
I almost always use Mobil premium which is 93 octane around here.
Southwest Mich? Im in the bend


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They are ****. I would replace on a biannual basis.


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I can't read. Ignore me.
 

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Plugs are new Volvo branded spec'd for the T5.
No codes have ever shown relating to these problems.
I will give it a day of driving and stay out of it a bit to see how it does.
When you state "no codes" is that with a generic OBD-II reader or Volvo's proprietary reader (VIDA/DICE)? If your car hasn't been interrogated with VIDA/DICE I recommend doing that. I chased a problem similar to yours for a long time on my S40 T5 with ~ 100K miles but I was getting CELs that reported out as multiple misfires in all cylinders on my generic OBD reader. I finally took it to a shop with the proper software and learned that I had a bad throttle body. Before that I first replaced plugs, MAF sensor, turbo control valve, turbo pressure sensor, turbo crankcase check valve and I cleaned the throttle body and checked the compression in all cylinders. I examined all my coils and considered replacing them but am glad I did not because they were visually in perfect condition. Oh, and I had also replaced the fuel pressure sensor several months before I started getting the multiple misfire codes. BTW, if it were to turn out that you have a bad throttle body I was quoted $800-900 to replace it. The throttle body itself is ~ $550-600 if I recall correctly. I found a used one for $60 and replaced it myself.

@avenger, the OP stated in original post that he had replaced the fuel pressure sensor, presumably before this current problem arose. ;)
 
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