lobo411
Well-Known Member
- Joined
- September 14, 2011
- Messages
- 925
- Reaction score
- 61
- Year, Model & Trim Level
- 1996 Explorer 4.0 OHV
Hello,
96 Explorer XLT w/ 4.0 OHV 160k...For years I had code 0420 intermittently, until I changed the DPFE sensor 3-4 years ago. Then it never came back. However, I nearly failed my last smog check on NOx (iirc fail was 800 ppm and I came in at 798 ppm) and I'm due for a smog check in May. The engine has been running fine since then: no codes, 20 mpg hwy/12-15 city,
I replaced the lower intake manifold, fuel injector, fuel injector manifold, and upper intake manifold gaskets to address a pinging issue and hopefully pass smog. This did improve my overall engine performance. I also bought an infrared thermometer to test the cat. I wonder if someone could check my procedure/results:
All tests done in idle at operating temp
Pre cat temp: Measured where Y-pipe meets the cat flange: 440 deg F
Pre cat temp: Measured Y pipe near driver's side oxygen sensor: 400 deg F
Temp near downstream O2 sensor: 400 deg F
Temp near the thing downstream of the downstream O2 sensor (is this the cat?): 300 deg F (this reading I'm not certain of)
I'm not sure where I was supposed to point the thermometer, to be honest. Thanks!
96 Explorer XLT w/ 4.0 OHV 160k...For years I had code 0420 intermittently, until I changed the DPFE sensor 3-4 years ago. Then it never came back. However, I nearly failed my last smog check on NOx (iirc fail was 800 ppm and I came in at 798 ppm) and I'm due for a smog check in May. The engine has been running fine since then: no codes, 20 mpg hwy/12-15 city,
I replaced the lower intake manifold, fuel injector, fuel injector manifold, and upper intake manifold gaskets to address a pinging issue and hopefully pass smog. This did improve my overall engine performance. I also bought an infrared thermometer to test the cat. I wonder if someone could check my procedure/results:
All tests done in idle at operating temp
Pre cat temp: Measured where Y-pipe meets the cat flange: 440 deg F
Pre cat temp: Measured Y pipe near driver's side oxygen sensor: 400 deg F
Temp near downstream O2 sensor: 400 deg F
Temp near the thing downstream of the downstream O2 sensor (is this the cat?): 300 deg F (this reading I'm not certain of)
I'm not sure where I was supposed to point the thermometer, to be honest. Thanks!