N52 29F4 and 29F5 codes

[DeafM5]

Yesterday, I had no choice but to fail the emission testing on my X5. The X5 current mileage is about 197k miles (2 years over 65k miles driven). These are only 2 codes that comes up on my autel. I don't know if having small whiff of oil smell randomly in the car can contribute to air leaks and I cannot find the leak around valve cover. I may have to pull intake side and refresh everything under there. What can I do to figure out this issue?

I will have new BMW Vanos solenoids installed today (they are currently transit by USPS). From maintenance/repairs standpoint, I am positive the vanos solenoids are original to the X5

Fuel trim
additive adaption of mixture bank 1 - .21 mg/Hub
additive adaption of mixture bank 2 - .13 mg/Hub
Multiplicative mixture adaption bank 1 - negative 0.8%
Multiplicative mixture adaption bank 2 - positive 0.8%

I have done repairs/maintenance on it over 2 years
-oil change intervals 7500 miles or sooner
-Bosch o2 sensors pre cats and post cats
-BMW valve cover (had valve cover leak bad enough to kill water pump)
-NGK spark plugs/WVE NGK coil packs
-New eccentric sensor during valve cover change
-bunch of gaskets replaced along with new belt tensioner (not related)

[dw280]

Are you able to smoke test the intake system? That would help reveal any potential air leaks.

Something similar to any one of these https://mechanicbase.com/reviews/bes...smoke-machine/

[DeafM5]

Originally Posted by dw280

Are you able to smoke test the intake system? That would help reveal any potential air leaks.

Something similar to any one of these https://mechanicbase.com/reviews/bes...smoke-machine/

I have an homemade smoke machine, but I need to order an attachment to plug the intake tube and then seal it.

[andrewwynn]

The "attachment" I used was a nitrile glove! (and rubber bands)

[andrewwynn]

Not engine related. I've had this issue on a few cars including my wife's e53 at a very similar mileage.

https://www.soupetl.com/products/90-...-with-mini-cat

Above is an example of the exact cure I used on wife's e53. I haven't looked at the O₂ sensor position on e70 yet so don't know if you need to use angle model.

They are very hard to locate in normal channels like eBay and Amazon apparently a crack down on people squeezing more life out of an aging cat.

When a cat reaches end of life it can't respond as quick to engine output changes and the post cat sensor sees this by following the change of the pre cat more closely.

An O₂ extender/adapter will smooth the output just enough to usually get a couple more years out of an old cat. Clearly the "powers that be" are making that option difficult. Your options are finding some extenders or replacing your cats.

I put one on my dad's 2000 sienna about a year ago and I think the code may have just come back. This is just a delay of inevitable but in the case of wife's e53 lasted until we sold the car.

[DeafM5]

Originally Posted by andrewwynn

Not engine related. I've had this issue on a few cars including my wife's e53 at a very similar mileage.

https://www.soupetl.com/products/90-...-with-mini-cat

Above is an example of the exact cure I used on wife's e53. I haven't looked at the O₂ sensor position on e70 yet so don't know if you need to use angle model.

They are very hard to locate in normal channels like eBay and Amazon apparently a crack down on people squeezing more life out of an aging cat.

When a cat reaches end of life it can't respond as quick to engine output changes and the post cat sensor sees this by following the change of the pre cat more closely.

An O₂ extender/adapter will smooth the output just enough to usually get a couple more years out of an old cat. Clearly the "powers that be" are making that option difficult. Your options are finding some extenders or replacing your cats.

I put one on my dad's 2000 sienna about a year ago and I think the code may have just come back. This is just a delay of inevitable but in the case of wife's e53 lasted until we sold the car.

The sienna of that year is the best. I had 2 (1999 and 2000) in the family and do miss them. They actually recommended premium for best results lol.

Anyways, this is what I am considering. I need to find out if I need angle or straight exenders. I found a post somewhere someone attempted to do it on their x5 and it fixed the check engine light.

[DeafM5]

UPDATE:

I checked for codes. I still had the SES lit up, but both bank codes were absent. I also used the opportunity to check o2 reading during cold start up and fuel trim reading.

The o2 sensors are reading perfectly in line with healthy cats. The fuel trim however is pushing about 1% on bank 2. Bank 1 is about 0.5%. Does this mean I have a very small air leak somewhere?

[andrewwynn]

Fuel trims are normal ± 5-8%.

[DeafM5]

Update 7/30/23

Currently at 204k miles and still showing the service light for cat codes. Vanos system seems to be working better with new solenoids. I sometime get very slight stumble but it quickly correct the idle. I get that stumble if I start it up and then shift into reverse/drive right away from cold.

I have ordered the new exhaust gaskets and bolts from manifold to exhaust. I have re used these gaskets when I did my transmission swap and since that day, check engine light would go on and off to the point it stays on now.

[andrewwynn]

https://jcarpart.com/products/copy-o...verter-generic

This is how I resolved the problem on about half a dozen old cars when the cats age they still work just not as efficient.

Defouler smooths the feed coming to the sensor so it will work a littler longer. Once the cats are gone this won't help but I've always gotten a few more years from old cats