2011 Volvo XC90 3.2 FWD with 122800 miles. Ive mad 2 prior posts about this vehicle so far and its been somewhat helpful. The codes im dealing with are
P0174- System Too Lean(Bank 2) {Code is both Permanent & Stored & Pending}
P0430- Cat System Efficiency Below Threshold(Bank 2) {Code is Permanent}
P2097- Post Cat Fuel Trim System Too Rich(Bank 1) {Code is Permanent & Pending & Stored}
P0107- Manifold Absolute Pressure/BARO Sensor Low Input {Code is Stored}
P0300- Random Misfire Detected {Code is Pending}
P0302- Cylinder 2 Misfire {Code is Pending}
P0301- Cylinder 1 Misfire {Code is Pending}
P0303- Cylinder 3 Misfire {Code is Pending)
Okay so Originally I was getting Both cat efficiency codes and the too lean code Bank 2, i proceeded to replace the downstream cats and all 4 sensors, no luck with getting the codes to go away, but they appeared way faster now. In The last post Scotty recommended I replace my upper exhaust manifold/cat converters as for the may have been dirty as well. So i replaced those as well(Its good to Note the Car Is Up to Federal Regulations Bin 2 & California Emissions according to the hood placard) and i replaced them with federal emission cats. During the wait for those upper cats, I replaced the pcv oil trap and the intake manifold seals, as well as got a new set of coils, oil filter housing, cleaned the maf sensor. After installing the new cats i drove the car and everything was great, no odd smells and the car was running way better then it has in 2 years. But the only lasted 20 miles and the check engine light came back for these codes P0174, P0430, P2097; with Cat, O2S. EGR, EVA systems all failing. I checked the fuel trim live data, Bank 1 Short Term was -7.4% and Long Term was -2.3%, Bank 2 Short Term was 62.8% and Long Term was 35.4%. With this i proceeded to check for any loose bolts or any possible exhaust leaks and everything seems snug. This stumped me so i decided to take a step back and take a look at the fuel injectors as for that's the only thing i hadn't did. So i got some Royal Purple Fuel System Cleaner and treated the tank accordingly as well as cleaned and inspected all the spark plugs, which had large amounts of carbon build up just under 10k miles on the plugs but the gaps were only .02/.03 off from oem spec. After 50 miles of doing that and clearing the codes, i plugged up my scan tool and then i got the same 3 codes from earlier but with the addition of P0107, and then 39 additional miles later(89 in total) i checked again with my scan tool and now i have all 8 codes I listed above at the start and those are currently being displayed, but this time only the CAT & EVA systems failed. The fuel trims on Bank 2 have went down slightly 3-5% on Long Term Trims and 6-8%on Short Term Trims. Im going to start by cleaning the MAP Sensor if possible and maybe get a fuel rail direct plug on cleaner tool if someone thinks that may help due to me not being sure how well those fuel system treatments really work. But at this point im stuck and have no clue what this could possible be besides maybe a slacked timing chain or unadjusted valves, but ive changed the oil every 5k miles since ive owned the car at 55k and haven't beat on it. SO that seems very unlikely but at this point who knows, any help would be very much appreciated, Thank You!
I would ignore the rest of the codes for now and go after p0174. A lean condition can be triggered by a vacuum leak somewhere that you haven’t found. The permanent codes are going to be reappearing everytime you scan the vehicle but it doesn’t mean there is something wrong with that component. Go after current codes first! You will need to perform a smoke test to find the vacuum leak, smoke the intake, and smoke the valve cover. Those are common to have PCV failures even though you just changed the PCV smoke it again and check for leaks. A very bad vacuum leak can cause all sorts of codes and misfires. I would stop throwing parts at it and do proper diagnostics. It may be time to take it in to a shop.
I don’t know about a cheap one but we use redline at our shop.
If the PCV is whistling it’s probably getting air. With the engine running remove the oil cap, if the car dies you have a vacuum leak in the PCV.
As far as smoking the valve cover there should be a hose from the PCV running up the middle of the intake to the valve cover. Remove the HOA at the valve cover and smoke it towards the valve cover. That same hose goes to the PCV smoke that end and look for leaks at the pcv.
i might be wrong with the location of the hoses I don’t have the car in front of me. I’m just going based on memory.
I did try taking the cap off while the engine is running and it just makes a loud hissing/whistle sound, not sure if its normal tho as for ive never removed an oil cap with an engine running before. And im gonna try to pull a vacuum diagram of the engine if i can to help me out
I just re-read my post and autocorrect put HOA instead of hose.
If you are hearing whistle you pcv is bad. On your vehicle is the pcv/oil trap bolted on the top of the valve cover or is it under the intake manifold?
the PVC oill trap is directly on top on the valve cover behind the ignition coils, its 10 bolts around its perimeter. I just replaced it but could it be a defective part? also there are no torque specs for it i read up on some forums of other people replacing it and called the dealer. Everyone suggests to go till its tight and an extra quarter turn
Also just to clarify there's a very faint whistle while the engine is running nothing like the videos ive saw of the same engine with the bad pcv oil trap. But if your saying that the whistling very loud with the oil cap off isnt normal and it could be related to the pcv then i definitely need to look into that part.
Ok, so you have the bolt on to the valve cover. Yes, if the whistle became noticeably louder when you remove the oil cap then I would replace the pcv again, it is not that surprising parts can be defective straight outta the box sooner ones. I would go with an OEM.
Tightening torque is 10nm for the oil trap.
Okay thank you so much, im going to get reimbursed on that part and buy the oem one. Should i still smoke test things on the valve cover to be safe?
You can just to make sure there are no leaks. If you have the smoke machine I would also smoke the intake you just gotta make sure you plug your intake hose the one that goes to the air cleaner otherwise your smoke is going to come out of there.
I’m pretty confident that replacing the oil trap will fix your lean conditions if you don’t find any other vacuum leaks.
Just found a pretty good deal on the same smoke machine scotty used in his video a while back for 70$ and 3 /4 day shipping. and could I smoke the intake by removing the maf sensor and taking the air box out of the equation. Only reason i say remove the maf sensor is because there are no real easy ways to get smoke in without going thru the air box, due to the only vacuum line i see to the intake being tucked away very low in an odd spot, either below or above the throttle body cant really see down there even with light. Also same kinda story with the valve cover, Would my best bet be the break booster vac line to smoke it? or could i use a power steering revivor bleeder attachment on the oil cap and smoke it thru there?(Ill make sure its a new attachment if i do that to be safe nothing foreign gets in the engine)
Or would trying to go via the oil fill cap, not do anything, im not honestly sure if its a direct passage to the valve cover if you understand what im trying to say
Yes oil cap should be fine. Get yourself some damp rags, not drench in water but damp enough to not drip. Then insert the hose in the oil filler neck and place your damp rags over the hose it would help from letting smoke escape outta there. If a little bit of moisture gets in there don’t worry about it will be fine.
Sounds good, ill be preform the test today
Alright so follow up i preformed the smoke test on the valve cover and there's no smoke coming out, i tried through the brake booster line and the oil filler cap. On the air intake after preforming the smoke test and found a missive crack/hole in the breather box coming off the intake tube. which is right above the throttle body so a bunch of un metered/measured air was getting in. I patched it up with some marine JB weld on the crack and the covered it all with plastic weld putty and let harden. After fixing this an installing I force cleared all the codes and drove it. The cars not running rough anymore I don't feel any vibrations from the engine and it doesn't hesitate at all anymore, engine has became very responsive. Everything was beautiful no check engine light for 10 miles, the long term fuel trim on Bank 2 was sitting right at 0 but the odd part was short term was still at 45% but I did see it drop to 0 not sure if it was during acceleration or deceleration. After getting gas within 3 miles of leaving the gas station the check engine popped for the Bank 2 Lean, Bank 1 post cat to rich, and bank 2 cat inefficiency. Also I did notice a slight egg smell as the cats where heating up and i could smell it coming from the manifold area with the hood open, so I'm going to smoke test the exhaust as well to check for any leaks before the sensors. And after as well.
So i preformed a smoke test on the exhaust and the intake again with no luck, the smoke was coming out from around the moist cloth after 2/3 mins of running the smoke machine. There was no leaks coming from the exhaust system i let it run for 5ish mins due to the larger exhaust system so it could get smoke all the way to the manifold, all the work I've done seems tight and there's no leaks. i wanted to know if i should try to make a better seal so smoke cant escape back out from where im putting it in or if thats only happening because there are no leaks and thats the only other place it can escape.
Im capable of doing the work, ive put in this many hours and I appreciate the tip, and yes it does have a minor whistle while running. Would you happen to know any cheap smoke machines that would fit my use? I have an e-cig but i assume that wouldnt be nearly enough smoke lol.
Also whats the best point to smoke the valve cover?