Emission Failure - High NOx - please help
03-21-2006, 04:00 PM
#16
Fleet of Foot
Rennlist Member
Rennlist Member
Randy, Randy, Randy... 
Three way cats have a mid-bed section which has the express purpose of reducing NOX emissions. You are thinking of the old two-way cats that did not have this function. All obd I equipped cars have three ways including our beloved sharks!
Three way cats have a mid-bed section which has the express purpose of reducing NOX emissions. You are thinking of the old two-way cats that did not have this function. All obd I equipped cars have three ways including our beloved sharks!
03-21-2006, 04:42 PM
#17
Rennlist Member
Hi Khaled,
Unhooking the vacuum line is not the right thing to do, it would be best to refer to the workshop manual pictures.
Unhooking the vac line would increase the fuel pressure due to the fact that there was not vac on the fuel pressure regulators. That is probal;y why the emissions were worse.
Regards
Unhooking the vacuum line is not the right thing to do, it would be best to refer to the workshop manual pictures.
Unhooking the vac line would increase the fuel pressure due to the fact that there was not vac on the fuel pressure regulators. That is probal;y why the emissions were worse.
Regards
03-21-2006, 07:53 PM
#18
Rennlist Member
Thread Starter
Ummm very interesting stuff in here. I will plan on the following then
New Plugs
New Injectors (for the heck of it)
New O2 sensor (why not)
If all else fails, i am taking the shark to Saudi Arabia anyways where nobody cares about NOx :-D but i do care about the car running clean.
Sincerely,
New Plugs
New Injectors (for the heck of it)
New O2 sensor (why not)
If all else fails, i am taking the shark to Saudi Arabia anyways where nobody cares about NOx :-D but i do care about the car running clean.
Sincerely,
03-21-2006, 08:17 PM
#19
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Once upon a time I *barely* passed - my NOx was just under the limit. The next year I changed the O2 sensor and my readings have been very good ever since. I used the "universal" O2 sensor from 928 Int'l.
John Pirtle
87 a/t 191k
http://members.rennlist.com/pirtle
John Pirtle
87 a/t 191k
http://members.rennlist.com/pirtle
03-21-2006, 08:47 PM
#20
Rennlist Member
- The O2 sensor is always a popular choice .... with reason.
- If there is a vacuum line open, Johns note makes a lot of sense re. enrichment.
- Should you still be reflecting on injectors, consider that a fouled injector will emit a poor spray pattern: this will lead to incomplete combustion in the cylinder and act as a lean condition. The unburned fuel speeds on to the Cat where it acts as if a false rich condition exists. All this drives even a good O2 sensor to drink! .... as it tries to regulate injector pulse width.
If only one injector is affected, the effect could be almost unnoticed: if more than one ....??
- If there is a vacuum line open, Johns note makes a lot of sense re. enrichment.
- Should you still be reflecting on injectors, consider that a fouled injector will emit a poor spray pattern: this will lead to incomplete combustion in the cylinder and act as a lean condition. The unburned fuel speeds on to the Cat where it acts as if a false rich condition exists. All this drives even a good O2 sensor to drink! .... as it tries to regulate injector pulse width.
If only one injector is affected, the effect could be almost unnoticed: if more than one ....??
03-21-2006, 11:35 PM
#21
Rennlist Member
Thread Starter
So many things... this is like black magic i swear. I think i will definitely redo my 02 sensor, plugs and try those Design II injectors... umm there goes another $500 
03-22-2006, 10:26 PM
#22
Burning Brakes
If your injectors are partially plugged your can run lean resulting the high NOx and the potential performance problems (like ping). I understand that they can be checked and checked for a reasonable amount (much less than replacement). At least that way you are not replacing good parts searching for a problem.
Catalyst can reduce NOx considerably if that is what they are designed to do. Generally the cat will reduce NOx during a rich cycle, the A/F ratio delivery is adjusted rich and lean based on the O2 sensor input to the fuel injection computer.
WICruiser
Catalyst can reduce NOx considerably if that is what they are designed to do. Generally the cat will reduce NOx during a rich cycle, the A/F ratio delivery is adjusted rich and lean based on the O2 sensor input to the fuel injection computer.
WICruiser
