Dash Icon---Help and Comments Solicited

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cammerfe

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I was out running around in the snowstorm yesterday, and after about the third stop, when I re-started the car, I had the little engine-shaped icon stay lit. The owner's manual says that this indicates an emissions fault. I therefore suppose that what's suggested is a cat that needs to be replaced. ???? There is no other indication of a problem of any sort.

The car runs just fine. I'm not very green-oriented and would just as soon not have to be bothered with it in this weather. I'm going to eliminate the cats along with the engine replacement in the spring.

Your comments are solicited.

KS
 
That light could be warning you about any one of a few hundred different faults. Get it scanned for OBDII codes to determine which area the complaint is in.
 
Its a check engine light and if you eliminate the cats you will have some issues with the o2 sensors.

Hook up a odbII scanner and try to see if any codes show up. not all cheap scanners will read all codes.
 
Thanks All!

Thanks for your comments and please keep them coming! I'd already intended to get a reading the next time I'm down that way!

An SCT re-set will take care of the oxy sensors. As an alternative, there are electronic gizmos readily available that mimic the output of the sensors in order to make it possible to eliminate them.

KS
 
do you have an sct?

some of them can read codes i believe.
 
you can bypass the cat codes by taking the rear o2's out of the exhaust and tie them to the underside of the car. leave them plugged into the harness. plug the hole in the exhaust with an oil drain plug with a copper gasket from the local parts store. size if i remember correctly is m18x1.50. should cost less than 10 dollars. the reason this works is because the rear sensors are strictly for emissions set by the federal govt. all they need to read is a difference from the front 02's/air fuel ratio sensors for the technical guys.
 
cammerfe said:
Thanks for your comments and please keep them coming! I'd already intended to get a reading the next time I'm down that way!

An SCT re-set will take care of the oxy sensors. As an alternative, there are electronic gizmos readily available that mimic the output of the sensors in order to make it possible to eliminate them.

KS
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They are called "rear O2 eliminators". Good luck finding any reliable ones for sale. Caspers electronics sold O2 Eliminators until the EPA shut them down... hard.

lsscott said:
you can bypass the cat codes by taking the rear o2's out of the exhaust and tie them to the underside of the car. leave them plugged into the harness. plug the hole in the exhaust with an oil drain plug with a copper gasket from the local parts store. size if i remember correctly is m18x1.50. should cost less than 10 dollars. the reason this works is because the rear sensors are strictly for emissions set by the federal govt. all they need to read is a difference from the front 02's/air fuel ratio sensors for the technical guys.
Click to expand...

Uhhh... not quite. The Rear O2 Sensors are there to check the efficiency of the catalist in the catalytic converters and by extension, to check and make sure the cats are still there.

Well, the rear sensors don't do any checking, they report back to the ECM which in turn decides how the catalyst is doing or if it's even there. They work on a square sine wave principle. The ECM expects a certain value to be returned by them based on what the actual O2 sensors before the cats tell it.

Was it instituted by the leaf lickers? Yes. But they are a little more complex than just taking them out and letting them flop around like a wet dick. First, they wouldn't get hot enough to work properly (and the ECM will know this) and second, they won't be sending out anything the ECM is expecting, if they are out of the exhaust stream.
 
You don't let them flop. A couple of zip ties work just fine. The o2's are heated so yes they will get hot enough. I have done this on several vehicles both import and domestic. They 'check' the efficiency as you put it. They are strictly emissions based sensors. Not engine performance.
 
I am aware they don't affect engine performance. But they will set a CEL and codes. What do you propose he do with the CEL? Take it out? Ignore it? Put some black tape over it?

You may have done this on several vehicles, but that don't mean it's the PROPER way to do it.

And please, don't insult my (and to an extent, other's who have actually done tuning) intelligence. If it was a simple matter of unscrewing the rear O2's and not worrying about the ECU setting codes/CELs, everyone would be doing it. But to properly do it, you either need a tune that turns off that part of emissions readiness checks or rear O2 eliminators.
 
not insults intended, but i have done plenty of tuning myself. and it doesnt throw and CEL's unless the o2 itself is bad. yes i do agree that its not the proper way to do it but it is a cheap way to take care of that issue until you have the money to go in with a laptop. technically messing with the emissions monitors within the computer on a emissions controlled vehicle is illegal and not for street use. not saying that i dont do it but as a tx state inspector if i wanted to be a real douche bag (and im not) if i saw that it had been messed with i can fail the vehicle for it. i never claimed that what i said was proper just an alternative. i prefer to go in with a laptop and just remove them.
 
lsscott said:
not insults intended, but i have done plenty of tuning myself. and it doesnt throw and CEL's unless the o2 itself is bad.
Click to expand...

So, what you're saying is that removing the rear O2 sensors from the exhaust stream will not cause a CEL? Computer only throws a CEL if the sensor is bad?

Tell me, how... exactly does the computer know the sensor is bad? Could it be something with the ECU seeing voltage values that are out of range for what it knows it should be seeing and it's not seeing said values? Like, for example, leaving the sensor out of the exhaust stream? No, it couldn't be something as simple as that, right?

The sensor doesn't have self testing capabilities. It doesn't send the ECU a memo when it dies in order to tell the ECU to light up that little CEL.

yes i do agree that its not the proper way to do it but it is a cheap way to take care of that issue until you have the money to go in with a laptop.
Click to expand...

Go in with a laptop? Why not just go buy a tune that addresses the issue? "Go in with a laptop..." Do you even know what you're talking about?

technically messing with the emissions monitors within the computer on a emissions controlled vehicle is illegal and not for street use.
Click to expand...

And your point, being?

not saying that i dont do it but as a tx state inspector if i wanted to be a real douche bag (and im not) if i saw that it had been messed with i can fail the vehicle for it.
Click to expand...

So, how exactly do you fail someone who leaves the sensors in place and turns them off with a tune, again? How, when every other state emissions stations merely check for OBDII Emissions readiness codes and or other non emission related codes? This varies from state to state, but as an emissions inspector, you know that Emission readiness codes are first and foremost the sniffer is looking for.

What, you take your "laptop" in to work with you and analyze someone's ECU parameters? Please.... don't insult my intelligence... tiny as it may be.


i never claimed that what i said was proper just an alternative.
Click to expand...

A very poorly executed alternative.


i prefer to go in with a laptop and just remove them.
Click to expand...

So, since you're such an uber tuner with your "laptop", tell me something:

What software parameters do you need to change in order to do this? Hint, there are 4 to 7 parameters you need changed to accomplish this task, based on the year, catch code and model.
 
lsscott said:
not insults intended, but i have done plenty of tuning myself. and it doesnt throw and CEL's unless the o2 itself is bad. yes i do agree that its not the proper way to do it but it is a cheap way to take care of that issue until you have the money to go in with a laptop. technically messing with the emissions monitors within the computer on a emissions controlled vehicle is illegal and not for street use. not saying that i dont do it but as a tx state inspector if i wanted to be a real douche bag (and im not) if i saw that it had been messed with i can fail the vehicle for it. i never claimed that what i said was proper just an alternative. i prefer to go in with a laptop and just remove them.
Click to expand...

The PCM looks for the O2 monitors to indicate that there is slightly less O2 in the exhaust after the converters than was detected by the O2 sensors before the converters. Just leaving the monitors connected but not in the exhaust stream will most certainly trip the check engine light. It won't do it as quickly as not having them connected at all, but it will do it.
 
joegr said:
The PCM looks for the O2 monitors to indicate that there is slightly less O2 in the exhaust after the converters than was detected by the O2 sensors before the converters. Just leaving the monitors connected but not in the exhaust stream will most certainly trip the check engine light. It won't do it as quickly as not having them connected at all, but it will do it.
Click to expand...

Funny cause i have done this on a GMC truck, a civic, and had to do it temp on a 2010 camaro ss after i put long tubes and a corsa exhaust on and none of them thru a code. the truck i put 20k on it and never had an issue again. but to be fair i live in the dallas, tx area where we dont get a lot of snow or sea salt.
 
Dude... seriously. Give it up.

You're trying to convince people who know a thing or two about this stuff that they are incorrect. Without turning off certain software parameters inside it or without plugging in "eliminators", the ECU will set a CEL if you remove the O2 sensors from the exhaust stream.

Snow or sea salt has nothing to do with it.

I'm still waiting for you to tell me which parameters I need to alter in the code to accomplish this, since you're on the record saying you've done plenty of tuning, yourself.
 
on what program tuner? and which code are you referring to that will be turned on. by number not some generic definition of 02 sensor bank 1 sensor 2 malfunction. be specific. im not claiming to know everything by any means i am always up for trying and learning new things. i am going off of my own experiences not something that someone told me or that i read on the internet. i am strictly saying that by not having the rear o2's in the exhaust stream they will not throw the dreaded p0420 and p0430 codes. and in my experience not other o2 codes.
 
Sh!t.. I'm not even a guy that's good with tuners and I can tell you that there is generic parameters that doesn't differ from tuner to tuner..

That's the only hint I'll give..
 
Frogman said:
Dude... seriously. Give it up.

....
Click to expand...

I think that we're the ones that need to "give it up." You can argue with a brick wall as long as you want to, but it will only wear you down, not the wall.
 
lsscott said:
on what program tuner? and which code are you referring to that will be turned on. by number not some generic definition of 02 sensor bank 1 sensor 2 malfunction. be specific. im not claiming to know everything by any means i am always up for trying and learning new things. i am going off of my own experiences not something that someone told me or that i read on the internet. i am strictly saying that by not having the rear o2's in the exhaust stream they will not throw the dreaded p0420 and p0430 codes. and in my experience not other o2 codes.
Click to expand...

Thank you for proving to us you have no idea WTF you're talking about. But, thank you for playing.

joegr said:
I think that we're the ones that need to "give it up." You can argue with a brick wall as long as you want to, but it will only wear you down, not the wall.
Click to expand...

I agree. I just wanted to explain to this guy that he's full of schit.
 
you still havent answered my questions. i dont use normally use the basic plug in tuners. i am used to stand alone units such as haltech and tuners that you use a windows based system to tune with where i have options to just turn the stuff off such as hpp tuners and life efi and ls1 edit. plugging in a superchips to a car and answering yes and no questions is not my idea of a real tune. but its whatever. everyone is entitled to their own opinion and i wont knock a guy cause he has his own way of doing things. like i said before im always up for learning new things and new ways to do stuff.
 
it doesnt have to take hours if the tuner is well equipped and has done that type of vehicle many times and has a great base map to start with, but yes i agree 100% that a from scratch tune can easily take 10+ hours depending on the car, modifications and what not.
 
But you can still create a good tune that will allow the vehicle to perform above factory spec without a dyno.

Just a matter of adjusting the proper parameters.
 
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