car failed emissions plug-in test, passed dyno
Thread Starter
Registered User
Joined: Oct 1999
Posts: 370
From: W.Mass
car failed emissions plug-in test, passed dyno
the inspection tech put me thru the ringer today. test overall took 1.25hours, he checked everything, and i mean EVERYTHING. you would thnk i pulled in w/ a beat up old clunker, when actually the car is better than showroom condition and only has 15,900mi on it. i know he only does what the computer tells him, but c'mon. anyway, he tried the plug-in test and it failed, so he had to put it on the dyno. all of the numbers look good except the NOX 1.88 (limit 2.00). he told me it was a sign that my O2 senosors were dying or perhaps the egr. is that true? what would happen if the O2s were to go? should I wait and worry about it next August? well, i now have to go clean up all of the finger prints he put all over the car. jeff
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1996 Blue-Green Chameleon Formula
1of70 Chameleon Formulas for 1996
2000 S10 LS 4.3L 4x4 PickUp
JeffsWorld
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1996 Blue-Green Chameleon Formula
1of70 Chameleon Formulas for 1996
2000 S10 LS 4.3L 4x4 PickUp
JeffsWorld
Registered User
Joined: Dec 2001
Posts: 177
From: Hanover, MA
NOx emissions are not something controlled by the O2 sensors. Generally it has more to do with either an egr or cat conv problem. However there are other items that can drive up NOx on an otherwise clean running motor.
As an example, if your thermostat were to only open partially it will cause your engine to run hotter than normal. This can increase NOx output. Also, if the shop fan that is supposed to be used during the dyno test is not properly placed it this too will cause the engine to run hotter due to lack of air flow thru the radiator. Given the heat wave we are currently going thru I would tend not to worry about it right now.
With regards to the OBDII hook up not passing, had you disconnected the battery just before going to the inspection station? This will clear the stored data and would show all or some of the OBDII tests as incomplete. As long as these test are not completed the inspection test will automatically kick your car into a full dyno run.
As an example, if your thermostat were to only open partially it will cause your engine to run hotter than normal. This can increase NOx output. Also, if the shop fan that is supposed to be used during the dyno test is not properly placed it this too will cause the engine to run hotter due to lack of air flow thru the radiator. Given the heat wave we are currently going thru I would tend not to worry about it right now.
With regards to the OBDII hook up not passing, had you disconnected the battery just before going to the inspection station? This will clear the stored data and would show all or some of the OBDII tests as incomplete. As long as these test are not completed the inspection test will automatically kick your car into a full dyno run.
Registered User
Joined: Dec 2000
Posts: 299
From: Clinton, MA
<font face="Verdana, Arial" size="2">Originally posted by JeffsWorld:
anyway, he tried the plug-in test and it failed, so he had to put it on the dyno. should I wait and worry about it next August?
</font>
anyway, he tried the plug-in test and it failed, so he had to put it on the dyno. should I wait and worry about it next August?
</font>
Next year you have to pass the OBD (plug-in) test. The dyno test is a backup for this year only. According to the RMV website, anyway. My car is due this month. I'm really sweating it, believe me. I'm pretty much screwed for next year....
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96 Ram Air Trans Am, M6, GTP Stage II heads, CC Xtreme 218/230-114,
Crane Gold 1.6I/1.5E, Hooker LT's, custom Mufflex 3" dual-cat y-pipe, Borla,
Meziere EWP, UD, K+N, SFC, STB, 94 PCM
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