fooling o2 sensors

[MTBracer367]

so my jeep, a 98 2-dr i6 ax-15 np231, has been running like absolute garbage due to a down-stream o2 sensor problem

i know that it is at least partly and o2 sensor problem becasude the check engine light is on and when i put a code reader on it i get to codes one being "system to lean" the other being "o2 sensor #2(downstream) high volts"

there is another problem relateing to poor quality of my engines preformance to is that the fuel presure is at 39-40 psi and being that mine is 98 my fuel preasure is susposed to like 49 psi and yes the gauge is working correctly and i retested it several times

i have had some bad luck with o2 sensor on this jeep like they keep riping them sleves out(the wires not the actual sensor)

there is also a leak in the weld in front of the cat that i guess could be causeing the off reading also because outside temparture has an extreme effect on how it runs it never runs right or good weather it's warmer or colder it just runs poorly in a different way if that makes any sense

so basicly as far as the o2 issue goes i'm thinking of just ordering those plugs that they make to fool the sensors but i don't know of any one that sells them or where to find them do any of you know of anywhere or have any other sugestions

i'm gonna try to fix the welds tonight if i can get the jeep up to my buddies house where my welder is but that won't be to easy it's to the point where it's hard to drive it


EDIT: the jeep also has a 62mm throttle body and a magnaflow cat-back exhaust with a punched out cat if you think any of that might have an effect on this

 

[wolfpackjeeper]

dude you have so much stuff gong on that you need to fix stuff before you start trying to fool the computer with gimmicks.

1) put a high flow cat back on, $80ish and I bet half of your problems go away. You are not getting any major or minor gain by running without one, at WOT and about 4500rpm maybe a small one. For the amount of trouble it can cause it is not worth removing.
2)check fuel pressure again(external gauge), and think about replacing the sending unit if it is bad. System too lean is probably not related to the O2 sensor, it is an engine condition being reported by the O2 sensor. Fix the welds while you are at it.
3)the downstream O2 sensor will not make your car run crappy, it will just tell you that it is running crappy and inefficient.

if you insist on running without a cat, you can make a spacer with a spark plug non-fouler. You just need to drill the interior hole deep enough for the O2 sensor to screw in, then thread it into the O2 sensor bung. I would only do this on the downstream, and only as a last resort.

 

[MTBracer367]

i didn't punch the cat out on purpose it blew out and i didn't have money for a new one at the time and it ran fine without one for a long time so it's not the cat i'm worried about it's more the leaks and in the exhaust and the fuel pump but i'm still interested in finding those plugs and yes i'm aware i have a lot of issue with my jeep right now but i didn't have a job for like 3 mounths so money was tight until i got my new job and now i'm trying to fix all the stuff i've been ignoreing

 

[wolfpackjeeper]

sorry, what I am trying to point out, is those plugs will do nothing for you but take money out of your pocket. They will not touch a thing that you listed. You can accomplish the same thing by making those spacers I mentioned. But all it will do is turn the code off for the high volts on the downstream O2. You can spend money on them, but non-foulers only cost about $10 a pair, where the dummy O2s cost around $1oo each. And it would only work for the downstream anyway. The upstream has to be a real sensor or the injection cycle will not work

The problems you are having are probably the cracked manifold, combined with a faulty fuel pump. Possibly a bad pressure regulator, but it is in the tank. Fuel filter could be a culprit as well. System too lean indicates either a fuel delivery problem, or air getting into the cylinders that is unaccounted for by the ecm.

Try fixing the manifold, throw some new plugs in, inspect the cap rotor and wires, zip tie the O2 sensor wiring up and out of the way, run some injector cleaner in it. Then pull the O2s and seafoam the motor. You can gently clean the O2s with a wire brush and then reinstall them. You can easily do all this and use a non-fouler on the downstream O2 for less than the $100+ you will spend on an O2 delete.

 

[MTBracer367]

ok so i went and welded up my cat a little better and reset the computer and it's running much better still not right but i think that has more to do with the pressure because of the hesitation i am getting when i floored it

there is also a noticeable difference in torque with the cat welded up thats how bad the leak was

and the reason i mentioned abotu the sensor reading lean is because (forgot to mention this in original post) it's running rich and yes i'm sure of this i've been around cars, trucks, quads, dirt bikes,and basicly anyhting else with a motor long enough to know what exhaust smells like when it running rich also when i would get on it it would smoke black but no it's not doing that and smells pretty normal not totally but better then before

and while sitting at my dentist's ofice today in the waiting room i was rethinking the whole fake o2 sensor thing and reliezed that they don't account for warming up the engine or anything or if there were and actual air/fuel ratio issue i wouldn't know until it was to late

 

[wolfpackjeeper]

depends, too rich will not hurt too bad, too lean... time for a rebuild.

It is amazing what a good exhaust will do with no leaks. I have noticed on my stroker that it actually seems to run a bit stronger on the bottom with a good exhaust/cat. I would give the computer some time to even out, even though you reset the code, and make sure there are no exhaust leaks before the upstream sensor. A tune up still would be a good idea. Especially if you have been running rich

 

[MTBracer367]

i already did a recent tune up like i said i've been around cars for a while and i'm not retarded i know to check things like that

and yeah running rich isn't that bad usually running lean = detonation and i like my connecting rods and pistons in one piece and inside of my block

and yeah i'm actully expecting the check engine light to come back on because i didn't get to drive it very much tonight due to time and cost of gas lol but there is deffinatly a noticeble difference we'll see how it runs in the morning swhen it's good and cold