kms0521

I have a 1997 993. I've had it 10 years and bought it with the CEL on with the P0140 SAI code. I have managed to clear the code and reset the monitors with the BMW Drive Cycle (or something close to that) for years, but I no longer can do it. Before, it was just the P0410 SAI fault code, but now I also have the P1411 (Bank 2) and P0303 (Cylinder 3 misfire). I realize I have some other issues going on, but should I still be able to reset the monitor, or do I eventually get SAI degradation to the point where I can no longer reset and I may be looking at some serious work (top end rebuild??) to fix the problem? Before I basically drove around 20 to 30 mph for several minutes, then upped it to 40 to 60 mph for several minutes, and then sat idle in drive for 5 minutes, always staying below 3,000 rpm. In fact, sometimes I think I just drove around and didn't pay attention all the much to speed, as long as I did some time at low speeds and some time at higher speeds (always below 60 mph), and made sure I was below 3,000 rpm. Nothing seems to be working now. Thank you for any insights any of you might have. kms

nine9six

Does your car burn oil excessively (1qt every 600-800 mi.) if not, you do not need a top-end rebuild.

Clogged SAI ports is different work and can actually be accomplished with the motor in the car. Read the applicable "sticky" at the top of the 993 forum for more info.

Most of the time that this code is thrown, the one-way SAI check valve has worn out or failed and allows oil in the exhaust and back into the SAI ports causing coking and clogging of the ports and can also have a negative effect on the air pump. When the PCM commands the pump on, if the pump is frozen it cannot turn, thus overloading the circuit and "popping" the fuse...So you may want to check that too. If the fuse is blown, its blown for a reason...

Jay777

How'd you pass emissions all those years?

User 122821

I've gone down this road before. Initially reseting the ECU will clear it and running the drive cycle will set the registers long enough to get through the SMOG check. As time goes on the SAI is blocked more and more to the point the ECU error is triggered sooner. The only long term solution I have found is using the brake cable with a drill to clear out the passages.

Jay777

My SAI situation is a little worse because the P0410 and P1411 codes on my '97 are pretty much permanent. But I found that if I go to emissions with the AIR monitor OFF (not READY), the codes are masked and I pass. https://rennlist.com/forums/993-foru...ere-s-how.html. I have found 2 drive cycles thus far that put my car in this readiness state, so I no longer worry about SAI.

Unfortunately in CA you can't show up with AIR monitor off like you can everywhere else, but there's still a possiblilty you can mask codes this way in CA if you time it right (see last post in thread).

Correction: in CA, any ONE monitor can be off , including AIR

SwayBar

If your oil consumption is acceptable, then doing the SAI port cleaning is not difficult and takes a weekend with parts in hand.

Fri - jack-up car, drop exhaust
Sat - clean ports, replace check valve
Sun - button it back up

Lorenfb

This only applies to late 993s, e.g. '98s, with the latest ECU firmware (PN 993 618 604 11).

kms0521

Thanks all for the replies. I actually cleared the monitors while driving to golf yesterday, Sunday, but alas, no stations were open. Couldn't get it cleared this morning but it was a Monday with heavy traffic. It really is sensitive to the drive cycle and I've found that 2 min idle at startup, followed by 3 to 5 min at 20 - 30, then 15 min at 40 to 60 mph, and finally idle again for a few minutes, all below 3,000 rpm, works the best. I've managed to pass smog all these years with this process, so apparently my emissions are ok. I've also noticed that the P0410 and P1411 are resetting much soon (they are essentially permanent like Jay777.

I'm also starting to add oil a bit more than in the past, but I am leaking through my timing chain cover and haven't dealt with the half of the cover where I'm told you have to remove the exhaust. Time to do that and ream the ports.

When would you say oil consumption is excessive? I'm only driving about 3,000 miles per year to give you an idea of utilization.

Cheers,

KMS

Churchill

You post does not, in fact, give anyone an idea of oil "utilization," insofar as "a bit" is not an actual quantity.

Jlaa

For the longest time, conventional wisdom, as you point out, has been that the brake cable / drill / clear out passages trick is the only reliable long term solution for this.
However, the other day I was perusing the ECU Doctors website and ran across this ---- does anyone have experience with a re-programmed ECU to bypass the SAI?
For ages I feel like people were running around in circles trying to figure out if there was a way to electronically bypass this --- but this is the first time I have ever seen one marketed for off road purposes?

Tlaloc75

Other vendors will do it as well. It would be nice to never have to worry about the CEL coming on, but I don't know if you can still pass emissions?

Jay777

There are only 3 requirements to pass OBD checks (see attached):

CEL bulb is "good"
CEL is commanded OFF
Required number of readiness monitors are set (READY).

Any hack that disables the SAI checks would technically work provided the above functionality was left intact, however you might want to Google "Penalty for tampering with vehicle emissions systems".
Hard to image a reputable company offering to do this.

JB 911

Funny they write for OFF ROAD purposes they can help you pass state emission tests. I like your system better Jay.

I am curious when my car turns 25 (3 more years) Texas becomes safety only (no emissions) what the legality of this ecu 'mod' might be. Id like to ditch the system at that point but not if it means having a CEL and not willing to remove bulb.

nine9six

As I am sure you are aware, a CEL can be thrown for a multitude of reasons and not just secondary air injector (SAI) failure/issue.

The ONLY function of the secondary air, is to speed the heating of the catalytic converter much like a bellows in a furnace. This has NO function whatsoever, with how the engine is running and the emissions.

Unfortunately, in the state of Kalifornia, if you have an existing check engine light (CEL) illuminated, a smog test station will not even test your vehicle until the check engine light issue has been rectified. Can you spell R-A-C-K-E-T? I knew ya could!

Conversely, your 993 could run as clean as the day it was born and well within stated limits and you still won't get a smog certificate to register your vehicle.

Yes, it is definitely a fuchs story, and because it's a racket that generates money illegally for the state and smog test stations, things are not about to change anytime soon.

Leander

Even the smog test stations suffer. I got my 993 tested yesterday. The proprietor said he had been forced into buying a new type of testing machine for use on older cars. I have no idea how much these machines cost but he said he was nowhere near recouping his "investment." Oh, my 993 passed.