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1991 3SFE failed NOx emmsions
Hello I'm new to this forum,
My '91 camry, auto 2.0 #SFE just failed NOx sniffer by over 500 parts, 1700+ where I think its supposed to be 1200.
Things I checked already:
Spark plugs: new (2 mos) but already whitened=high engine temp
cooling system: just flushed with new thermostat, temp sensor in spec
Intake vacuum at idle: steady at 23 in Hg
IAC: in spec according to chiltons
O2 sensor: in spec accoring to chiltons
MAF: in spec according to chiltons
TPS: out of spec, replacing in 2 days
EGR: new modulator and BMSV check valve, EGR valve in good shape and opperates properly according to chiltons, EGR pipe has no build up and appears to have no leaks. To be noted though vac. reading between EGR valve and modulator at 2500rpm fluctuates between 7-12 in hg rapidly. I assume this is exhaust pulse from EGR pipe and OK.
All vacuums lines appear to be good with no leaks.
Car starts and runs well, doesn't hesitate (good throttle response) and appears to have good power although I have only owned this car for 6 months and don't have a standard to compare the power to. Car averages 23-26 mpg with mixed driving. Never runs hot according to temp gage.
Other than replacing the TPS what should I look at that might be causing the high NOx emissions? Is there a way for me to check the catalytic converter? It was already replaced 4 yrs ago by the previous owner. The car has good flow out the tail pipe without the "Pop or Sputter" it would get if the exhaust was blocked/clogged. Also is there a way to check the fuel pressure regulator?
I also intend to check the ignition timing to see that it is close to 10', not over advanced.
Thanks in advance for any input, sorry for the long post.
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