89 BWM 3 Series 2.5Lfailing smog

I'm trying to help a friend get their BMW to pass smog.

The problem is that it is failing all gases. Yikes.

So, I was hoping for some tips on what to attack first.

Thanks for your input.

Here's the info

(limit, measured)

1762 RPM 15 MPH
%CO2: 14.2
%02: .6
HC PPM: ( 108, 197 ) fail
CO %: ( 0.5, 0.52 ) fail
NO PPM: ( 527, 1985 ) more than fail

The CAT was replaced last SMOG test, 2015, which allowed it to pass. At that time, only NO was high, (537, 816). HC and CO were very good.

I have not had a chance to physically look at car yet. I want to determine what to attack first.

The only known issue is that that battery keeps losing its charge.

She said she has a new alternator, new voltage regulator, and a couple year old battery.

My proposed process:
1) Attack charging system issue since perhaps the alternator isn't allowing for good spark.
2) See if I can connect a scan tool to it to obtain any information possible
3) Verify O2 functionality
4) Attack the EGR system due to high NOx.

Thoughts?

Update:

Fixed starting issue. It was caused by a really poor connection at the positive post of the battery. Car starts every time now.

But, car seems to be running super rich. I'm going to test vane MAF. I'm hoping that it is stuck open.

Any thoughts?

Update:

Vane MAF checked out. I performed the snap throttle test and it had the appropriate wave form and acceptable mins and maxs.

O2 heater worked, pulled 1.5 a

O2 seemed lazy at idle but looked ok around 1500. At idle if would take 2 seconds or so to cycle. Whereas at 1500 and above, it cycled at 1 second.

So, would the O2 be enough for this car to be so rich?

I used an infrared thermometer at the CAT. I was a little surprised it was around 140 F at inlet and around 130 F with the exhaust manifold at 600 F. Doesn't that mean the CAT is dead?

Any thoughts? Anyone? No one has said anything to me.

sorry we dont have smog testing here so not much help on that part . it wouldnt suprise me if cat is dead if its been running rich i assume those temp readings are after full warmup?

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I don't know other techs experiences but I never placed much faith in the cat temperature test especially at idle even more so if the O2 content of the exhaust isn't being controlled by the upstream sensors -- rubbish in rubbish out.
Not only do O2 sensors get lazy as they grow older but also drift out of calibration. On an upstream sensor I look for 3 crossing counts per second even at idle --- ie a complete "sine wave" going zero-low-zero-high--zeo. A new sensor will typically do twice that or better.

That mode has a common problem with vane maf and the rubber . Have you checked the coolant temp sensor?

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Hey! Thank you for your input.

Since my last post, I have tested the ECT and spark wave forms.

According to the Verus component test information, the ECT looked good but more on this later....

The primary spark waveforms looked great. The secondary spark wafeforms looked decent. They just didn't seem consistent and sometimes the initial voltage seemed low.

The tail pipe still smells rich.

I do remember when I was testing the MAF, it had a clean waveform. But, what I noticed is that the ECT readings just seemed so hashy. I wonder if the alternator is applying noise to the overall system. I was connected to both sides of the ECT sensor. Yet, when I tested the MAF, I had the ground to the block.

Hmm. Do you think that indicates anything????

I'm going to check out the alternator and spark plugs for my next round of tests.

I also want to check out the IAT along with any other sensor I can get at.

have you checked the spark plugs? black spark plugs will indicate running rich..
is it just one? all four?
I can't see how the IAC will make run rich.