It's been a while since i've had my cam only car and my car now is not even running cause of the transformation it's been undergoing for a year so I can't remember if it is normal or not for oxygen sensors in the front (those which control the trims) to throw insufficient switching codes or not in a cam only car with headers. Is this a sign of failing oxygen sensors or are then just slow because of the cam and the headers placing them farther away from the exhaust gases? Thanks.

 

cold condition caused by too much gas or too much air

 

So then you're saying which of the following: 1) the headers and cam are a cause of this and it should be ignored; 2) the car is running too rich or too lean (but it's not because i've verrified with the wide band that it's floating around the 14.7 to 1 range during closed loop cruise); or 3) the oxygen sensors are bad and need to be changed? Thanks.

 

it could be any scenerio listed above, installing headers will usually cause pcm to dump more fuel in drownin out the O2 sensors, cam could go either way, or bad sensors...a tune should take care of the problem...the problem shouldnt be ignored if you plan on keepin closed loop operation

 

Well like I said this car driving down the road is maintaining close to the magic 14.7 to 1 number during cruise that the oxygen sensors commands so although the sensors are throwing these codes it seems the car is still running within a good range. His trims move around but fall between +10 to 0 so i'm not too concerned there. Just don't want to tell this guy to get himself some new oxygen sensors only to have the same problem with the new ones. Thanks.

 

chances are the code is trippin at idle, so i'm guessing you need to look there

 

Ok, thanks for the suggestion.

 

np, good luck

 

When you say it's running down the road at 14.7, are you checking that with a wideband or just scanning the car and reporting what the computer says. If you're just scanning, you're looking at the "commanded AFR" not the actual. The other problem with headers (besides movong the location of the O2's farther away) is that they dissapate much more heat thus affecting your O2 switching (especially at idle). You might want to look at them and see if they are all carboned up and maybe you can clean them.

 

Insufficient switching is the first bit of whining you're
going to get from headers making the sensors cold.
They can still be functional, the "enough switching"
is an arbitrary test for normalcy and you left normal
behind a few mods back. As long as you have some
activity out of them, and the waveform remains roughly
symmetric (alternating high and low, similar time above
and below 0.5V) they'll do the job. When you see them
spending most of the time pegged low and jumping up
every once in a while, you can expect fueling errors
are resulting.

 

I'm using a wide band guys for verrification, i'd never rely on anything the car's sensors tell me, ha.

Sounds to me it's more along the lines of what I thought, this is just going to be how it is with the cam and headers for this guy. To be honest when my car was cam only i'm sure i've turned those codes off or atleast not to illuminate the SES light so i'll have to go back and double check. His oxygen sensors still switch at a relatively reasonable rate and the fact that he's close to stoich while driving would indicate to me that they are still functional and accurate. Thanks.

 

I will tell you ALL right now. Insufficient switching MAY NOT BE due to headers.

my problem was injectors. I have racetronix 36.5ers and yes it can be due to headers but log what you have to find out and see where they are crapping out at

 

 

so muncie21, everytime someone has a issue with 02 codes its cuz of headers right?

every car is different. i don't have time for stupid forum arguments, so if you think its the headers.. fine. won't post in this thread anymore

 

I'm agreeing with you, bonehead.

 

didn't know man, didn't know. sorry.

 

I thought someone posted in the last month that if you change two tables it will increase switching rate.
Phil

 

???

 

If the lack of switching is due to fueling issues, as opposed to cool heaters (due to LTs) then you can increase/decrease switching by adjusting the fueling tables.

I had to do this for my idle O2s as they were happy being stuck at 900mv all the time.

 

here is a pic from my log, I can send the log to someone if they want.

a friend that had about the same problem was due to the injectors :
Quote from WS6FirebirdTA00: "Find out from the EFI boys if they have a table which controls the amount of fuel the injectors shoot to make the o2s switch. In HPT its called proportional fueling. This is where you problem is, nothing with the switch point. I would put them back to stock and set up a scan so you know at XX airflow what mV you see for the AFR you want. If you find this table we can take care of it, the problem is coming from the injectors. The computer is commanding large fuel swings, which with bigger injecotrs is even larger. This makes the o2 readings rail at idle (you can see that in the log).

I am willing to bet as long as the o2s are ok, which I assume they are, that if you put your stock injectors back in the code will go away."

so what tables do i need to try and play with?(I would really like to see if i could get these injectors to work fine as they are, so i can sell them and say there are no problems as long as you do this....

Headers have been on my car for over 20k miles
injectors have only been on the car for ~4-5k miles and they were fine until about 800 miles ago