Check Engine Issues! 1997 e36 328i Sedan

[two2huts]

Hi Folks,
I'm a little bummed.. having spent almost $4K on suspension problems the past year replacing pretty much everything.. I now am running into engine issues. The car has 122K miles on it and I took it to a independant mechanic, here's what they are saying:

"...(1) Fault Code 229: Control Frequency, Oxygen Sensor 1 - Too large in rich range, currently not present, fault frequency 4x

(2) Fault Code 233: Total Catalytic Converter Efficiency, currently not present, fault frequency 9x

Recommend Replacing all 4 oxygen sensors to resolve fault code 233, (if same fault is logged after O2 sensor replacement recommend replacing catalytic converter)

Performed Manometer test, noted reading slightly higher than normal, recommend performing smoke test to check for unmetered air leaks for fault code 229 (possible faulty PCV valve)..."

The upshot is that it's going to cost $1200 for the 4 O2 sensors (and possibly replacing the Cat at $2500). Plus another $500 for the PCV valve replacement.

That's another $4K of repairs to clear the fault codes!

I can't sell the car at this time since it's not going to pass smog.. so I was hoping someone could help with some ideas to fix the fault codes without costing so much.. while I'm no mechanic I would welcome fixing things myself.. how hard is it to replace O2 sensors, do I really need to replace all 4? Can I get an aftermarket Cat (exhaust system) instead of paying for OEM parts? Would you recommend replacing everything or is there one item that I should fix which may be the only problem?

Anyway.. any help/encouragement appreciated..

[E36 Phantom]

Going to cost WHAT to replace four O2 sensors??? I don't know where you went but run man.

If you're actually in the City, I don't know anywhere that's really close, but for the price it's well worth the drive - check out MotorSpeed West in Santa Clara. They do good work and have some killer prices, and are great about explaining things to you. Call them up and tell them the 2 codes and get their opinion on it.

If you don't mind some DIY work, replacing O2 sensors is a piece of cake and you can get them for about 80/ea. Also, try just replacing the one O2 sensor first, and see if that helps your 233 as well.

[two2huts]

Hey thanks for the quick input.. I'll definitely check out MotoSpeed West... after I posted that I found some instruction on Pelican Parts for replacing the O2 sensors. I'll do some DIY for sure! Where can you get O2 sensors for 80/ea? I found some for $116/ea at Bavauto.. Also any idea on what the 229 could be? Is the PCV suggestion a good one?

Thanks!

I'm feeling much better already!! :-)

[E36 Phantom]

I forgot where the info is, but there's a generic Bosch O2 sensor you can buy at Kragen or anywhere for the 60-80 range. You have to connect your own wires, so it's not quite plug and play, but if you have to connect 4 O2 sensors, it comes down to whether or not the extra $160 is worth it to crimp a few wires together. I'd go for the generic ones myself. Sorry I don't know which off-hand. Of course, try Kragen for the specific ones anyway, they might have 'em cheaper.

Here are a few thoughts from reading over that more carefully.
-If you have unmetered air, you'd be running lean, not rich. If that's saying the O2 thinks you're running rich, that should be unrelated to vac leak.
-A frequent cause of running rich is a dirty MAF. A can of CRC MAF cleaner at Kragen will run you 6 bucks an 15 minutes of time. Try cleaning it first.
-I'm confused by "Cat Coverter Efficiency - currently not present." I wonder if that means a reading isn't present, or the O2 doesn't think a cat's present because of low delta or what. Maybe ask them what exactly they mean by that.

What shop are you at?

[Chris S]

HERE O2 sensors cost about the eqv to $300 at the $tealer ...each and the auto stores dont carry alternatives so... well VERY expensive to fix even with DIY

[two2huts]

The shop I went to is German Motor Specialist (Sunnyvale). I think they were basically quoting me the BMW replacement parts (they don't do OEM or Bosche ones) - which is why it's was $225 each! + labour.

At this point with an 11-12yrs old car I'd go with the cheapest.. the Bosche ones seem fine to me.. hopefully won't impact performance.

I actually asked about the MAF since I replaced in the intake with a cone version.. I thought that might be causing some issue. I'll do a clean to see if it'll fix it.

I'm translating the "Cat Coverter Efficiency - currently not present" as the O2 sensors are not reading a change in the emissions before and after the Cat.

One last thing.. I'm now contemplating getting an OBD II software and connector so I don't have to spend the $125 in diagnostic fees everytime I take it to the shop. I think I'll need this to also reset the faults once I fix all the issues.. any thoughts?

Thanks!!!

[E36 Phantom]

Uh-oh......the intake cone, did you go with K&N or a similar oiled type filter? Were the codes on before this?

OBDII readers are great. You can spend $50 to get a super-basic one that just gives you the # and lets you clear, or you can spend $250-350 and get ones that let you monitor various fields, record max values, etc. If you're serious about DIY, you can grab the pricey ones. If you just want a basic code reader, the cheapy ones will do just fine. IMHO, the mid-range ones are kinda pointless. Either get the basic or get serious.

Or, call around and find a place that does free code scans.
Doesn't have to be a BMW place, just anywhere that will read your codes w/ an OBDII scanner, then you can call shops with the codes and ask their opinions. :angel:

[two2huts]

I think I'll stick with a basic one.. it'll give me a good idea and if it's a simple job it'll allow me to fix it reset it. I don't really have a garage to get really serious with the DIY (YET!).
The intake cone is a non-oiled base one from AFE.. http://www.modbargains.com/product.aspx?pf_id=AFE_BMW_E36_Intake_MW .. I've had this one on for about 30K miles perhaps it just needs a clean.. it would be awesome if both faults got resolved by cleaning the air filter :-)

Anyhow.. thanks so much for the input! Really appreciate it!

[E36 Phantom]

The aFe filter is a good one. Glad you didn't get an oiled one :) those are very known to allow oil to blow by the filter element and contaminate the MAF. Cleaning the MAF could resolve it. Cleaning just the air filter will not, although cleaning it is never a bad idea as long as you follow directions and make sure the solution is completely rinsed off and the filter is completely dry before you reinstall.

Best of luck!

[two2huts]

Oh hey.. one last thing.. should I start the MAF clean or the O2 sensor replacement? Do you think I'll need to do both anyhow to resolve both fault codes? Or perhaps MAF might clear up the other fault code also.. nah??

[E36 Phantom]

KISS.

Start with the MAF.

[two2huts]

I bought a $24 CodeKey OBD II reader!! Reads & Resets - Nice!

Started the MAF & Air Filter Change.. but check this out!!

http://www.thepartsbin.com/catalog/index.php?N=9167+1580+9718+4294965875+11921&Ns=price2%7C0

Are my eyes decieving me.. how can one part go from $20 -> $225 in range for the same part!!?