cali smog help e30 keeps failing nox! help!

[efficient]

like my title says. my friends e30 1989 325i keeps failing smog due to high nox.
-I've cleaned the fuel injectors, on the injector machine.
-checked for vacuum leaks using a smoke machine. found none.
-decarbonized the pistons with sea foam.
-plugs got changed
-changed the fuel pressure regulator.
-also did a fuel pressure test and it has around 40psi and when you pinch the line the fuel pressure bumps up. fuel pressure was good according to bentley.
-cat was changed.
-Oxygen sensor was replaced.
-plug wires been replaced and checked if its getting spark.
- replaced the thermostat and bled the coolant so the car runs at the proper temperature.
we also did another test run at smog with 91 gas and the 15mph went down a little but nothing close enough to the max. i don't know what else it could be. any suggestions?
trying to fix this car to pass smog legally.
cali smog:hitler:

Untitled by clean3two3, on Flickr

[efficient]

Ttt

[bmwman91]

How recently was the cat changed, and with what type?

According to a SMOG-Lambda calculator, your values mean that you are running a ~16.3 AFR at both speeds. That is either from a big vacuum leak somewhere, a bad O2 sensor or non-stock injectors with a lower flow rate. You said that you checked all of those items, so it is hard to say. Stock chip in the ECU?

[efficient]

How recently was the cat changed, and with what type?

According to a SMOG-Lambda calculator, your values mean that injectorsou are running a ~16.3 AFR at both speeds. That is either from a big vacuum leak somewhere, a bad O2 sensor or non-stock injectors with a lower flow rate. You said that you checked all of those items, so it is hard to say. Stock chip in the ECU?

The cat was changed like in may and the last time the smog was don'e was in June. It was replaced with a magnaflow cat made for a 325i. The stock injectors i cleaned made the car run smoother. it also has a 173 dme with stock chip. We put propane gas on the fpr hose and the car would run rich and stumble when we gave it more propane but as soon as we close tje valve the car runs lean according to the machine that shows what's going on.

[bmwman91]

Could be a busted AFM reporting bogus air flow values. See if you can get a hold of a known working one and swap that in. Aside from SMOG, running 16+ AFR's isn't a great recipe for long engine life either.

[jlevie]

I have seen two cases where the DME was causing AFR's or 16-18:1. It or the AFM would be my suspects in this case.

[efficient]

Could be a busted AFM reporting bogus air flow values. See if you can get a hold of a known working one and swap that in. Aside from SMOG, running 16+ AFR's isn't a great recipe for long engine life either.

I have seen two cases where the DME was causing AFR's or 16-18:1. It or the AFM would be my suspects in this case.

we swapped afm's. i just passed smog and i let him borrow my afm but not the dme's. I'm sure running on pure air isn't good at all for the car but as of now its been sitting.
would loose valves cause high Nox? not closing properly? i noticed they were a little loose but didn't think anything of it.

[kung fu jesus]

High NOx is a lean running engine, as pointed out by the previous responses. Your A/F ratio is way out of wack. Valves not closing properly would read high in HC as unburnt fuel would be finding it's way into the exhaust.

[efficient]

High NOx is a lean running engine, as pointed out by the previous responses. Your A/F ratio is way out of wack. Valves not closing properly would read high in HC as unburnt fuel would be finding it's way into the exhaust.

hmmm......

maybe we will swap dme's and see what happens.