M30B35 Failed Smog! :(

[Jean]

My b35 just failed smog with Stock DME, 2 year old cat, new plugs/wires/cap/distributor.

I wanted to smog it last time to buy me some time for the v8 swap....going to re-test it tomorrow and then m30b35 is coming out.

Replaced an O2 sensor today with a new one.

I don't recall how old the O2 sensor is, reading about high NO I guess it could be O2 causing a lean condition = high temp?

Suggestions?

Pretty much everything on this engine is brand new as of 2 years since it's been rebuilt top to bottom. Valves were adjusted a month or so ago, and oil change and plugs done at the same time with a new cap/distributor as well.

15mph -
CO2 14.0
O2 1.7
HC 34 (ave is 31, max is 112)
CO 0.09 (ave is 0.10 , max is 0.72)
NO 1053 (max is 778 )

25mph
CO2 13.9
O2 1.8
HC 27 ( ave is 20, max is 86 )
CO 0.09 (ave 0.09 and max is 0.60
NO 909 (max is 717))

[Jean]

Will me luck tomorrow, if it fails oh well I guess I'll deal with BAR in a few months :/

[LJ851]

I'm not in a hurry for your mounts, jean. Take all the time you need to pass that test.

A fresh cat is always helpful, is yours aftermarket?

[CHIF8008]

most e30 cats only last about 2 years anyway since its pretty much the only smog controlling item on the car.

[LJ851]

most e30 cats only last about 2 years anyway since its pretty much the only smog controlling item on the car.

Aftermarket ones, yes. Oem ones can last 10+ years (higher platinum content)

My last bosal cat lasted 5 years.

[ForcedFirebird]

Correct me if I'm wrong, but in Cali if you swap an earlier motor into your car, the emissions have to abide by the chassis, correct?

Also, from what I understand, high NOx is a result from no EGR and/or lean conditions (both causing high combustion temps). A bad o2/cat will not cause this or have an affect on it. A faulty IAC/CTS/AFM or vacuum leak can cause this and would check for the easy stuff before going back or spending on parts.

AFM test and rebuild (for Porsche, but uses same values): http://www.the944.com/afm.htm

The CTS needs to be 2.2-2.7k ohms @ 68*F and .3-.36k ohms @178*F

[Jean]

How are you saying o2 has no effect if the dme relies on it for its fuel mixture?

In my case engine is newer than the car and was already bar'ed.

[ForcedFirebird]

How are you saying o2 has no effect if the dme relies on it for its fuel mixture?

In my case engine is newer than the car and was already bar'ed.

I'm saying a bad o2 won't necessarily cause high NOx. The DME relies on other sensors as well, o2 is just part of the equation in the math the ECU uses in the chip. CTS is a heavy part of that equation as is the AFM.

It could be as simple as a maladjusted TPS. If it never hits the idle table, it's in the low part throttle map, specially seeing this is just a switch.

[Jean]

Ok, regarding TPS. Since the test is done at 15 and 25mph it's not at idle where it's high on Nox ?

[LJ851]

Ok, regarding TPS. Since the test is done at 15 and 25mph it's not at idle where it's high on Nox ?

Shouldn't be an issue @ 15 and 25. The intake air temp sender will affect mixture. Your CO is pretty low (lean) but thats post cat so we really dont know what the engine is actually seeing.

[Jean]

Ok

So I gotta go check

TPS
AFM and Temp Sensor.

[Grand525]

Fuel Injectors?

[Jean]

They are rebuilt and flow tested.

[KenC]

High NOx is usually a bad cat. If you think it's OK, it was probably too cold. Even at idle it'll cool down.


I just traded my 318is to a guy in LA. It failed CA smog that day after passing OR with flying colors. He drove the ever living piss out of the car and took it back when it was nice and hot. It then passed CA smog easily. I'd just beat on it then take it back when you can pull right in without idling in a line. Just something to try before spending $.

[wannaBMthree]

loosen the valves?