Ok guys..my car at FIRST was throwing a Too Lean (Bank 1) code and a fuel trim malfunction code. I bought an OEM primary O2 sensor and replaced it...the codes went away. About a few days later my check engine light turns on again and now it says "Catalyst Efficiency Below Threshold (Bank 1)" so far everything is leading to either my CAT..or my secondary O2 sensor right? Considering the primary O2 sensor is brand new. I checked my spark plugs today and they were greyish and had a LITTLE bit of tan, but the plugs were no where near brown, which made think I was still running lean. Now I'm getting a new code saying I'm Too Rich (Bank 1)..and the Catalyst code...??? any ideas? I still have good gas mileage so I do not think I am running rich.
I called the Tech guys at Acura..and he said even though my plugs are not brown or black that I might still be running rich..that the plugs can fool me????...Any ideas on what I can do to fix it? Or please let me know what is the most important..I want to fix part of it (the most important part) by next friday. If it is the CAT..does anyone recommend the carsound magnaflow unit? Will that most likely fix my CAT code..and does anyone recommend any certain type of O2 sensor? I would by the universal ones..but don't know if I might wire it wrong..anyone have a picture of how it looks wired..or a write up.

Sorry for the essay, but it's the only way I can let everyone know what is going on..

Thanks in advance!!

 

Just a couple of q's
How long did you drive with the bad O2?
Probably your secondary O2 has gone too, not the cat.
Have you reset the computer? to see if the codes are false?

If you did drive for a while your cat could be bad. If you don't have the correct A/F ratio you can burn out the cat pretty quick.

 

Well, at first..my car was running lean..and I couldn't afford to fix it right away..so I set my fuel pressure at about 40-42 psi..to run a little more rich..yeah yeah..I know that might have been what's causing these codes..but hey..my engine hasn't blown..so I'm still somewhat happy! Hmmmm..I thought my rear O2 sensor..doesn't have anything to do with my air/fuel ratio..though..? some people just have them hanging in the air or put O2 simulators...any ideas if a bad CAT can cause my running rich code?? Also, I check my plugs again...and the hook looking thing that sits over the electrode is greyish..but the round part it's attached to (the part at the very end after the threads that the hook is stuck on) look to be black..but the hook thing is grey..is this indication of me running rich? Car still has good gas mileage..

 

A bad cat will not cause a rich code. Did you readjust the FPR after you replaced the primaryO2? The primary is for A/F ratio's
Plugs black = rich Good would be greyish black with a tan tint.
The second O2 is for cat efficiency. You don't have anymore codes for it do you?

What is happening is your computer is seeing a rich condition and trying to adjust to get it to lean out, but is not able too, thus your rich code.

 

Yeah, as soon as I installed my primary O2 sensor..I set the psi back to 36 psi..which is stock. The only codes I have is Too Rich (Bank 1), Catalayst Efficiency Below Threshold (Bank 1) and Fuel Trim Malfunction...



The part that is black on these plugs following the threads is pretty black on my plugs..and the hook thing is greyish..this is a pic of good plugs...so I guess the black is ok..as long as it is not on the hook part...If I replace my rear O2 sensor will the rich code go away? I never had the rich code until after I replaced my primary O2...I just hate taking it to shops..because they just tell me what I already know...and just check the CEL!!! What do you suggest I replace first? I'm at work..if you want you can e-mail me at DGastelum@firstam.com..Oh one last thing..I thought since my rear O2 doesn't have to do with air/fuel it wouldn't make my car run rich..will sea foaming my car help it?? Also, I can sea foam it today, probably! but would I have to change the oil and spark plugs right away? I can do that next week.

Thanks for all the help you've been giving me!!

NOTE: This is not a pic of my plugs..but something I found online for an example.

 

I adjusted my Idle adjusting screw all the way to the right (I think) to make the idle higher..because my car would stall when I would come to stops..any ideas on if this might make my car run rich? Oh..and since my car isn't wasting more gas than normal..is it something that might not be to critical?

 

Yeah, as soon as I installed my primary O2 sensor..I set the psi back to 36 psi..which is stock. The only codes I have is Too Rich (Bank 1), Catalayst Efficiency Below Threshold (Bank 1) and Fuel Trim Malfunction...

Too rich (bank 1) - Your computer is seeing a way rich condition.
Catalayst - is from your secondary O2 having a fluxuating reading (normal would be a steady .1 to .2v output)
Fuel trim malf - computer is trying to correct the rich condition and cannot.

Have you checked the output from the primary O2 sensor. Just to make sure that is good. If it is then the cat eff. below thres. Secondary O2 check this voltage too. Like I said this voltage should not fluxuate like the primary.

Check those two out and we will go from there. as for the idle air screw? I haven't messed with that I just bend the tab to adjust the idle. You might try and back it out a bit and see. Did you reset the comp and these codes are reappearing?

 

I haven't reset them yet..but now I am noticing a little decreas in gas mileage...it's a brand new O2 sensor (primary) how would the output be bad..and what can I do to fix it if it is? Oh and how would I check it to see what output it is at? I'll check both sensors when I find out how to do it but still like I said before..I thought the secondary O2 sensor doesn't have anything to do with air/fuel...if that is the case it's not too important right now..my main focus is getting the rich condition fixed...any ideas on how long I can drive with being rich and not messing up my O2 sensor? I wanted to switch it back to the old one for the time being..but the old one was making my car run lean..and if that happens I will have to bump up the fuel pressure again..and if I do I might mess something else up!! Thanks for the help you've been giving!

 

Reset the ECU first.
This is what I stated before:
Catalayst - is from your secondary O2 having a fluxuating reading (normal would be a steady .1 to .2v output) Secondary O2 is for cat efficiency ONLY!

As far as a bad primary 02, they do come from the store bad, if dropped or something.

I don't want to write out the testing for the O2's please search for me.

But reset the computer! Once the check engine light is on it goes into"Limp mode" and in this mode it will run rich because it is trying to save your engine.

 

Well to begin you should probably never touch an idle screw on a car that's not carburated especially an OBDII vehicle as the vehicle will just compensate for it. And to really see what's going on you need a scan tool that can see your sensor outputs and LTFT. And so you know most newer cars with O2 sensors read lean when they fail, creating a rich condition that may kill your cat but save the engine. So if this was the case you ecu will err on the side of lean and richen the hell out of the air fuel mix. And like the smogman said O2 sensor normally don't go bad on the shelf. And as much as people hate it, OBDII can usually do a damn good job of finding emissions related failures.

So the first thing I would try to see what the secondary O2 is doing.

The best thing to use is an O-Scope if you have one but a scanner should do and a digital voltmeter might be able to see it but if the secondary is bad then the transitions may be too fast to catch.

But thesmog man is correct, it should remain very low and steady if it jumps around and especially if its matching the primary then you cat is junk.
Secondary O2 sensors tend to not go bad as often as primary since they aren't exposed to as much "crap"

If you are going to attemp a reading with a digital voltmeter backprobe the connector with a pin at the signal wire with the + on the meter and connect the negative to battery ground.

Here is a good informative website.
http://www.aa1car.com/library/o2sensor.htm