I just had the emissions tested on my 1988 Town Car. It passed every test well, except for the NO (nitrous oxide), which it failed miserably, with twice the allowable emissions. Anyone had this problem or know the possible causes??
Any info would be appreciated.
EGR problem.
Check your EGR valve for correct operation, all related vacuum lines and EGR solenoid and vacuum regulator if equipped. There also might be two 1/4" metal tubes coming from your exhaust and egr feed lines for backpressure sensing. Sometimes they rot and break off.
Normally an EGR system problem. You need to have the ECM scanned for any fault codes. Problem could be bad EGR valve, EVP sensor, plugged tube, vacuum leak or other problems. You also need to make sure the ignition timing is correct. Some parts stores like Autozone will scan it for stored codes
Lugnut
Thanks for your help everyone,
I'll get right to work on it.
When my Dodge cargo van tested high on Nitrous Oxide, I couldn't find any OBD computer codes to explain it. I took it to a mechanic who replaced the O sensor and catalytic converter. I think it was the catalytic converter that fixed the problem rather than the O sensor which wasn't very old at the time.
C. E. White wrote:
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