Failed emissions - High NO

[cmk]

Was rather suprised to fail my emission test today.

ASM2525 Test
HC : Limit 52 Reading 0
CO : Limit 0.29 Reading 0.00
NO : Limit 385 Reading 626 (FAILURE)
RPM : 1661 (how do they get this ?, they didn't open the hood)

Curb Idle Test
HC : Limit 200 Reading 0
CO : Limit 1.00 Reading 0.00
NO : N/A

I went through the archives and looked at some of the other threads but didn't find anything definitive.

The general consensus seems that it's due to running hot, yet the temp is pegged at center, put in a new rad and full flush last fall. Temp is fine.

I've usually taken it to a dealer (where it passes no problem), but this time i took it to a small hole-in-the-wall around the corner. Is there any way they could have screwed things up ?

[colo525i]

Don't see how there could be 0 HC and CO readings, those should both be there. Unless your car is running on water laced with nitrogen fertilizer! Try taking it elsewhere, those numbers make no sense.

[Jon K]

to get the rpm they use an inductive pick up that picks up rpm pulses from cars electronics.

[attack eagle]

certainly.
How does it fail to emit ANY carbon monoxide OR HCs at 1600 rpm? Does it run on magic blueberries or something?
Go elsewhere , I think they are looking to make rent this month.

[cmk]

I agree that the 0/0.00 for HC/CO are weird, but the last test (2004) had the same but with NO = 286.

The test before that (2002) had HC/CO/NO = 3/0.00/0 ... so i can't seem to win for tryin', i find an NO = 0 equally as improbable. Although in 2001 both cats were replaced (warrenty).

Each test was done at a different place (all before current at dealers).

I'm going to replace the plugs/oil/filter this weekend.

If i can get some O2 sensors from Bruno (for a reasonable $) i might replace those as well. Looking back through service records they've never been replaced - car at 191kkm. From what i've read the O2 sensors wouldn't give the results i'm getting, so it's more preventitive than maintainance.

[yaofeng]

Get GTP (Gaurantee To Pass) from Pepboys or any parts store. What have you got to lose for $9.95?

[SnakeyesTx]

Worked for me on a beat down 91 caddy with the 4.9 V8 with bad o2 sensors, bad cat, and bad MAP

[cmk]

I've been thinking about doing that but i'm concerned that they will gunk up the injectors and/or plugs. I'd rather fix, than patch, the problem.

[BillionPa]

0HC and high NOx = lean running, get new O2 sensors and fix you vacuum leak!

[cmk]

From what i've read a failed O2 sensor will cause it to run rich.
http://www.autohausaz.com/bmw-auto-p...n-sensors.html