Emissions -- Bah Humbug! - ZR-1 Net Registry Forums

SoCalZR1 · 06-15-2010

Hello everyone. Before I get into the smog headache I just wanted to introduce myself. My name is Mike and I live in The OC. I am new to the forum but not to the Registry. Just looked, I have a registry sticker on my car from 1996. The sticker is okay but the car is not looking as good as back then. :-)

Anyway, the problem. The poor beast had been sitting around too much and I decided to get it back up to snuff. I replaced the bad fuel pumps and all 16 injectors. They were leaking bad and I almost had a hydraulic lock once. All seemed good after that. Went to get a smog check and then it was not as good. It almost passed but missed HC at 15 MPH.

HC
Max allowed: 77 (Max was 110 last time it was checked. Go figure!)
Measured: 115

Nox
Max: 541 (772 allowed last time)
Measured: 437

Went home empty handed.

Drained fuel, since it was old and filled with new; Cleaned and re-oiled K&N; removed DRM PROM and inserted stock; replaced spark plugs.

Since the car is 1990 it has to go to a "Test Only" station. Took it to a regular smog first and just had them do a pre-test. Numbers were great! HC was in the high 40s, NOX below 200. That was just eyeballing it.

Confidently returned to "Test Only" and the non english speaking, ignore that I am here dude and he ran it again.. FAIL:

Now HC was good but NOX failed:

HC
Max allowed: 77 (Max was 110 last time it was checked. Go figure!)
Measured: 70

Nox
Max: 541 (772 allowed last time)
Measured: 738

What gives?

I will say that the pretest was done in first gear at 15mph. The robot dude at "Test Only" says it should be second gear. Really!? Second gear for 15MPH? That means 1271 rpm.

Any ideas. Would new O2 sensors help (easy)? Why the sudden NOX problem? I know I changed a lot of variables after the first, but I can se the problem there.

Any ideas would be much appreciated.

06-15-2010	#1
SoCalZR1 Join Date: Jun 2010 Location: Southern California OC Posts: 22	Emissions -- Bah Humbug! Hello everyone. Before I get into the smog headache I just wanted to introduce myself. My name is Mike and I live in The OC. I am new to the forum but not to the Registry. Just looked, I have a registry sticker on my car from 1996. The sticker is okay but the car is not looking as good as back then. :-) Anyway, the problem. The poor beast had been sitting around too much and I decided to get it back up to snuff. I replaced the bad fuel pumps and all 16 injectors. They were leaking bad and I almost had a hydraulic lock once. All seemed good after that. Went to get a smog check and then it was not as good. It almost passed but missed HC at 15 MPH. HC Max allowed: 77 (Max was 110 last time it was checked. Go figure!) Measured: 115 Nox Max: 541 (772 allowed last time) Measured: 437 Went home empty handed. Drained fuel, since it was old and filled with new; Cleaned and re-oiled K&N; removed DRM PROM and inserted stock; replaced spark plugs. Since the car is 1990 it has to go to a "Test Only" station. Took it to a regular smog first and just had them do a pre-test. Numbers were great! HC was in the high 40s, NOX below 200. That was just eyeballing it. Confidently returned to "Test Only" and the non english speaking, ignore that I am here dude and he ran it again.. FAIL: Now HC was good but NOX failed: HC Max allowed: 77 (Max was 110 last time it was checked. Go figure!) Measured: 70 Nox Max: 541 (772 allowed last time) Measured: 738 What gives? I will say that the pretest was done in first gear at 15mph. The robot dude at "Test Only" says it should be second gear. Really!? Second gear for 15MPH? That means 1271 rpm. Any ideas. Would new O2 sensors help (easy)? Why the sudden NOX problem? I know I changed a lot of variables after the first, but I can se the problem there. Any ideas would be much appreciated.