MDamen

I have had the CEL on for over two years. The codes are for the SAI. A year ago I started cleaning out the ports and found I had a corroded SAI manifold that would not hold cleaning fluid or air. I buttoned it back up and have been living with the CEL.

With the recent article on the SAI circuit I decided to build one and see if it would work since I need to get the emission inspection this month. Over the weekend I built the circuit, installed it and cleared the codes. This also clears all the readiness flags.

I drove the BMW cycle two times to reset the codes and then headed to my local inspection station not knowing what the real condition was. All I knew was there was no CEL showing. I passed on the first try. The results showed that 7 of 8 readiness flags were set. The only one not set was ... you could guess... the secondary air injection.

Washington will let you get by with one (maybe 2) readiness flags not set if you have no CEL.

I don't know if the lack of the SAI readiness flag is a result of the circuit installed or not. I still don't know if I will get the CEL once the readiness flag sets. I don't even know what part of the drive cycle will set that flag. In general, I don't care for two more years when I have to get it tested again, but wanted to share my recent positive experience and will update as I drive with the circuit longer.

I guess I could also experiment and disconnect the circuit and see if the CEL comes back right away, but for now I am enjoying driving with no CEL.

Update below.

Lorenfb

"The only one not set was ... you could guess... the secondary air injection."

So it appears that the circuit did not function, i.e. since the SAI readiness
code should have been set if the circuit properly grounded the O2 sensors
when the air pump turned on during a cold engine start.

"I still don't know if I will get the CEL once the readiness flag sets."

If the CEL occurs, then the SAI readiness flag will not set.

"I don't even know what part of the drive cycle will set that flag."

The SAI readiness test occurs at start-up with a cold engine.

g_murray

Hmmmmm.

Since the readiness flags (for the SAI pump) didn't 'set' then I am suspicious of THAT aspect of your car, be it the circuit-board, wiring, etc. etc.
THAT flag, 'if everything is kosher', will set pretty darn quickly - like others that set quickly - such as the misfire monitor etc.
Again, if everything was kosher (be it thru' a GOOD SAI system, or thru' circuit-shennanigans) then THAT flag should have set 'quickly'.

I'd venture to say that after you cleared your CEL and ran the BMW drive-cycles that 'enough' readiness monitors were set to satisfy your state's demands, and that's all. I readlly don't see any evidence that the SAI 'problem' has been addressed, if you get my drift. It's really really taking too long for me to say that it's 'addressed'.

The readiness monitors that take a whooooooooooole lotta time to 'set' are the two for the catastrophic converters but that's because they have a whoooooooooooole lotta testing to do -timewise, efficiency-wise (it takes time for those suckers to heat up and 'work as advertised' and return a 'working within parameters' signal to the ever-vigilant and non-negotiable OBD-ii system.)

Summary: For your catastrophic converters (which take a whooooooole lotta time) to be 'set' and your SAI monitors (which 'know' at startup whether something is amiss or not - and thus are set lickety-split.) to NOT be set?

Big HMMMMMMM.

Gerry

skl2

I just cleaned my ports and had the same issue with the SAI manifold - one of the metal plugs had corroded and blew out, so air and cleaner was just coming out that hole. I ended up removing the manifold, JB Welding both plug areas and reinstalling. Worked like a charm and all is well now.

Slow Guy

I'm curious how you would get a CEL if the Readiness Indicators have not set in the first place?

I'm going thru this right now w/ my '97 M3, 7 of 8 RI's set but the Sec. Air has not yet set (even after 8 - 10 drive cycles). No error codes thru either the OBDII tester or the (BMW specific) Peake Tester.

Update: Just an FYI but on my M3 I replaced the 2 Pre-Cat O2 sensors and after just 2 warm up cycles the SAI RI finally set. I didn't even have to do the drive (I'd done 8 - 10 already). Just started and let it idle for apx 5 min. while I took it down off the lift (I had done an oil change too) and parked it outside for the night. Started it up the next AM and let it idle for 2 -3 min. w/ the tester attached and when I started to do the drive it was already set (and posted "Done"). Got it inspected and passed just fine.

Quadcammer

You wouldn't. The readiness indicator only sets once its gone through its test. If it fails the test, you get the CE light and you're back to square one.

MDamen

I would have expected the SAI flag to set fast, since that is tested during the first part of the drive cycle at idle. Should I keep repeating the cold start up idle to try and get the flag to set? Will the CEL eventually come on if all the readiness flags don't set? I read other posts where people drove their car for months and all the flags did not set. I still don't have a CEL or any error codes.

I plan to fix the SAI manifold when the engine comes out for a clutch change. I couldn't figure out how to get my hands and tools in there to get the manifold out with the engine in the car. It looked next to impossible or require extreme patience.

I'm satisfied that I passed emissions, but I'm not sure if it is becuase the circuit is working, or there was some other reason I had not gotten any error codes thrown yet. My only success may have been in getting two more years to sort this out. The SAI issue may not be addressed yet.

Slow Guy

You can get to it after you remove both sections of the air filter housing. I'll post pics of my SAI flush on my first 993 later.

User 122821

Congratulations on your success.

My experience with or without the circuit, is the SAI readiness is the last to set. Yes, the procedure says it's the first test but I don't believe that passing that initial test sets the SAI readiness based previous experience of the SAI readiness was always the last to set.

Before using the circuit, I would run through the BMW drive procedure twice and then go straight to the SMOG station for testing without shutting the engine down. At this point I would have 7 of the 8 readiness set. Of course soon (1 hour - up to 1 day) after the SMOG test, the CEL light would go illuminate but at least I had another 2 years. I was just getting lucky.

With the circuit, I don't have to count on luck. It's taken 3 months for the SAI readiness register to set with the circuit installed. Go figure.

g_murray

OK, now THAT's a lot different than your first post.

And a positive one too!

THAT says that the circuit-shennanigans has worked because the SAI-system (which is NOT working on your car) - has, essentially, been 'faked', faked as in 'working-faked' and has satisfied OBD-ii.

Congrats!

Gerry

MDamen

Update:
I did a long idle on cold start up a couple more times, as in the first part of the drive cycle. After 2 days it set the SAI readiness flag and also threw a CEL. The code is P0410. Before I was getting a P1411, so it could be that the circuit is making it look like the SAI pump is not working. I'm not sure and I don't have a OBD2 reader that will tell me what's going on. I can borrow an Equus 3130 from my local auto parts store. It will record live data. I just need to know what to look for.

I was just lucky to pass emissions. I'm still looking for the SAI solution.

User 122821

Bummer. Sorry to hear it. Sounds like circuit is not the fix all.

rpaitich

Mike Damen:
Please tell me what transistors you used in your circuit. Did you make any changes to the circuit? The O2 voltages are not high, and the type of transistor could make the diff. I too am interested in this fix; I believe i understand the operation, and the circuit should work.

MDamen

I'll check the specifics of the parts. I had to make choices on the voltage rating of the capacitors, but I didn't think that what make a difference. My recollection was that I used exactly the part number of the transistors. I'll check my invoice tonight and update with the data.

Here are the components I used.

I got all the parts from Jameco

Jameco part number description
51182 transistor 78L05 +5v to -92
36311 diode 1N914
691024 resistor 4.7k 1/4 watt 5%
94035 CAPACITOR,TANTALUM,4.7uF,16V,10%
26833 CAPACITOR,MYLAR,.001uF,100V,10%

MDamen

I might get this going yet. Looks like I have the wrong transistors.
Looking back at my order and the schematic I can't figure out what I was thinking when I ordered those. That's what I get for being an ME and not an EE. I can't tell a voltage regulator from a swtich.

Thanks Ron for checking my work and setting me on the right path.!