Pissed off owner-PART 2-What is going on?

[hink12341234]

You know my story from from pissed off owner. Stealth has a miss can't figure what it is,blah,blah,blah. I went out today and disconnected the O2 sensor and the car runs perfect now. Does this make any sense? Dang if I know. Drove it for 45 minutes figuring the CEL would come on since the O2 sensor is disconnected.No CEL. Am I missing something here? The reason I disconnected the sensor is I thought the problem had to do with the air/fuel mixture. I thought it was running too rich. I thought this might fix it for awhile but also figured the CEL would come on and then the car would run like crap since the 02 had been disconnected. Any reasons why this worked? Many thanks.

[2old]

You have a exhaust leak or bad O2 sensor?

The CEL can be reset if you disconnect the battery (the code is there but the CEL does not light up).

It sounds like the engine has gone into default mode with the O2 sensor disconnected.

[hink12341234]

Originally Posted by 2old

You have a exhaust leak or bad O2 sensor?

The CEL can be reset if you disconnect the battery (the code is there but the CEL does not light up).

It sounds like the engine has gone into default mode with the O2 sensor disconnected.

You say the code is there but the CEL does not light up? Is there a reason it does not light up? I have tried to figure this problem out for some time now and this is the first time that it has ran right in quite awhile. I feel i'm very close to finding the fix. As far as the exhaust leak being the problem would the leak be coming "before" the 02 sensor or after? If that's the problem it would seem to me it's leaking before the 02 sensor and the sensor is sending the incorrect signal to the computer. If the leak is "after" the sensor it wouldn't make any difference. Thanks for your advice.

[2old]

Well this is my from my experience... If the CEL light was tripped before and the battery was disconnected the CEL light will not turn on for that code again until it's fixed.

This means that the 02 sensor could have malfunctioned before and disconnecting it would not trip the CEL light.

On my car I had a exhaust leak in the header gasket which what bad enough to make the car stumble at low rpms/high torque applications but not throw up a CEL code. About 6 months after that was fixed, my 02 sensor failed and then 1 year after the catalystic converter clogged (I am guessing this was the chain of events: exhaust leak caused the engine to run rich, fouled the O2 sensor and overheated the cat... But I am not exactly sure)...

Hope that helps...

[AutostradaVR4]

02 sensor should be cheap enough. Might be worth your while to go ahead and replace it. Even if it doesnt solve the problem, at least thats one more variable out of the equasion.

[hink12341234]

The 02 sensor was a new one. Just got done driving it(02 still disconnected)and ran perfect. I was a mailcarrier and since 92 I drove Dodge Spirits with the 3.0. One day on the route when I would put the car in reverse and go forward the engine would die but it would start right up. No CEL. I thought this was very strange. I knew the 02 sensor was old so I replaced that and that fixed the problem. I never had that problem before. The local Dodge dealer told me when in doubt change the 02 sensor. He couldn't understand either why the 02 sensor would cause the car to die when you put in reverse. Now with my car running good i'm hesitant to plug the sensor back in.

[2old]

Disconnecting the O2 sensor makes the ECU to use the default A/F ratio...

In the short term it's fine, but it will evetually foul the cat which is more expensive to fix then changing the O2 sensor or scanning the ECU for codes (i guess if you don't care about emissions it doesn't matter)...

Meanwhile you should check the exhaust for leaks in front of the O2 sensor to at least see if the problem is obvious (frayed flex tubing, smell, etc.).

I have also "broke" a new O2 sensor before (6 months old and no voltage across the terminals) so it's not unheard of these things breaking right away...

[hink12341234]

I have the car on stands right now and will be checking for exhaust leaks. What you say makes sense. I'm hoping is there is a leak it should be easy to find. I have a stethascope and the good old rubber hose to listen for leaks.

[Igovert500]

As 2old said, disconnecting the o2 sensors, just makes the car run in open loop mode. 02 sensors aren't the only thing that causes CELs to come on. To trigger a CEL a system check has to fail. Each system has different parameters necessary for the check...and many include the car to be in closed loop mode. Therefore disconnecting the o2 sensor really doesn't tell us a single thing.

I honestly don't remember what you posted in your first thread, adn that's why it's a bit annoying to start a part 2 thread, but overall, we need a code, and you need to start trouble shooting based on that code. Not disconnecting o2 sensors.