Deq

MtDewd

Registered User
Took my car to DEQ today and it failed on the total hydrocarbons (THC). They were double what they are supposed to be.

The car has been running a little rich because when I pulled the codes I get "adaptive fuel lean limit reached, rich reading right side" and same for the left side. I also get ACT out of range.

Could the air charge temp sensor be making it run that rich? I cleaned my O2's a couple weeks ago, maybe I need new ones.

Looking at the graph for THC's, they seem to be well within limits when the car revs up but when it goes to an idle they shoot way up. I have been having a problem with the idle dropping below 500 when I come to a stop but then it catches itself and returns to normal idle.

Any ideas?
 
Welcome to the club, sortof

I've got high Nox. But creeping HCs.. still within limits. If your O2 sensors are going out (at least the gabby but not always right clerk at Azone told me this) then they usually cause it to run rich!

Well that doesn't fit my problem very well because high Nox usually results from high combustion temps which would indicate too lean, but then again on the 90/AOD, there just isn't a heck of a lot of anything OTHER than the O2s. In my case, I'm guessing that new O2s will help my problem, in your case though you have codes, or at least a code. Maybe you need a new ACT sensor. Its the sensor which screws into the plenum on the driverside.

As far as your idle speed, I'd suggest you take a look at the engine mounts.. No, I'm not kidding.. engine mounts. There's a very good chance that unless the've been replaced that they are collapsed. Post back if you need info on what to look for.:)
 
It's not the mounts because I put in solid rubber ones about a month ago when I rebuilt the motor.

I did replace the ACT today and it helped just a little, still failed. It's close though. Maybe I'll just have to break down and buy some new O2's.
 
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