failed smog .. high nox - Page 3 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1992-1999 Series I L27 (1992-1994 SE,SLE, SSE) & Series II L36 (1995-1999 SE, SSE, SLE) and common problems for the Series I and II L67 (all supercharged models 92-99) Including Olds 88's, Olds LSS's and Buick Lesabres Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 08-22-2004, 10:17 PM   #21
Senior Member
True Car Nut
 
Join Date: Sep 2002
Posts: 3,392
Thanks: 0
Thanked 0 Times in 0 Posts
fuddyduddy121 is on a distinguished road
Default

Here'* the first code. Not sure about the second. Can you recheck?

The EVAP purge valve allows manifold vacuum to purge the canister. The Powertrain Control Module (PCM) supplies a ground to energize the EVAP purge valve (purge ON). The EVAP purge valve control is Pulse Width Modulated (PWM) or turned ON and OFF several times a second. The duty cycle (pulse width) is determined by engine operating conditions including load, throttle position, coolant temperature and ambient temperature. The duty cycle is calculated by the PCM and the output is commanded when the appropriate conditions have been met:

Engine coolant temperature above 25C (77F).
After the engine has been running about 2 1/2 minutes on a cold start or 30 seconds on a warm start.
The vehicle is operating in closed loop fuel control.
Canister purge commanded duty cycle varies according to operating conditions determined by mass air flow, fuel trim, and intake air temperature.

Canister purge operation is also affected by throttle position.

VIN K -- Canister purge will be disabled if TP angle increases to above 70 percent. Canister purge will be re-enabled when TP angle decreases below 66 percent
VIN 1 -- Canister purge will be disabled if TP angle increases to above 33 percent. Canister purge will be re-enabled when TP angle decreases below 29 percent
The EVAP vacuum switch is a normally closed switch positioned in the purge line between the canister and the EVAP purge valve. The EVAP vacuum switch will open when vacuum increases to greater than 5 inches of water (in. H2O) in the purge line. The PCM monitors the EVAP vacuum switch signal to determine if the evaporative emission control system is working properly. If the switch is open (purge flow detected) when the PCM is not commanding the EVAP purge valve ON, DTC P1441 will be set.
fuddyduddy121 is offline   Reply With Quote
Old 08-22-2004, 10:29 PM   #22
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Apr 2004
Location: bay area, ca
Posts: 42
Thanks: 0
Thanked 0 Times in 0 Posts
xkeithx is on a distinguished road
Default

p1870 has to do with the transmission slipping, it went out about a year ago and we had a rebuilt tranny put in. or they rebuilt the old one.. im not sure. where exactly is the evap vacuum switch located? is it inside the canister?
xkeithx is offline   Reply With Quote
Old 08-22-2004, 10:44 PM   #23
Senior Member
True Car Nut
 
Join Date: Sep 2002
Posts: 3,392
Thanks: 0
Thanked 0 Times in 0 Posts
fuddyduddy121 is on a distinguished road
Default

I'm not sure with your car, try this:

http://134.39.200.6:9001/home.html
fuddyduddy121 is offline   Reply With Quote
Old 08-23-2004, 04:54 PM   #24
Member
Posts like a V-Tak
 
Join Date: May 2004
Location: San Diego,Ca
Posts: 97
Thanks: 0
Thanked 0 Times in 0 Posts
GreenMachine is on a distinguished road
Default

xkei,

Besides EGR, I believe a faulty CAT converter could also cause high NOX. With 187,000 miles on the car, that might be worth looking into.
GreenMachine is offline   Reply With Quote
Old 08-23-2004, 07:10 PM   #25
Member
Posts like a V-Tak
Thread Starter
 
Join Date: Apr 2004
Location: bay area, ca
Posts: 42
Thanks: 0
Thanked 0 Times in 0 Posts
xkeithx is on a distinguished road
Default

a new cat is what im thinking now also. i took the car in to a local shop and the guy tested the egr valve, it works fine. maybe this would fix the hard starting problem ive been experiencing also?? as i said before sometimes when i crank the engine the EVAP vacuum line and the fuel pressure relief vaccum line which are both plugged into the throttle body will pop off and the car will stall. i couldnt figure out what would cause them to pop off, there is supposed to be vacuum pressure holding them on. would it make sense for a clogged cat to cause enough backpressure that these lines would come off??
xkeithx is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
NOX emission failure for 1998 grand prix gtp Sean_6969 Pontiac 3 01-23-2012 10:54 PM
Gross Pollluter, HIGH NOX sp4149 1992-1999 24 07-19-2007 03:35 AM
Failed NOx Help? kaps 1992-1999 16 09-08-2004 10:16 AM
bonnie failed the nox in emission test rrrddgy 1992-1999 4 03-01-2004 02:21 PM
Smog Test Results? billha 1992-1999 2 03-21-2003 12:56 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 07:22 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.