420A P0140 Car Stalls

[Kslam1981]

97 base 420A. Slight miss during idle but coming to stops the RPM's dive low and the car stalls, once I come to complete stop its all good, and occasionally stalls on take off until u get on the throttle.. Few times it even stalled out.. Replaced plugs/wires, swapped the coil pack and the IAC, checked the intake for leaks, cleaned the throttle body (wasnt even dirty) then give up on it for a bit. Ran the same for about 3 weeks now and today I finally get a check engine light and get the code read but it come out with P0140 no activity detected Bank1, sensor 2. Is'nt that just emissions junk??? or can that sensor really have an impact like this??

 

[stars]

They use it as a reference for the ecu to tell if the car is running too rich or too lean. O2 sensors are very important because they take reading both upstream and downstream of the catalytic convertor. Too rich of a fuel mixture can harm your convertor and they are not cheap to replace when they stop up. They are around the $700-1000 range so it is best to get your o2 sensor replaced. O2 sensors are about $80 if you shop around. You car will run better because now it has a sensor that it can read off of and adjust your air to fuel ratio accordingly.

 

[xcasbonx]

Don't worry about replacing the downstream O2. You could try replacing the upstream one at the downpipe. Going to cost you around $80 bucks give or take for a new one.

 

[Kslam1981]

so this is the 02 located under the car around where the front seats are on the exaust line?

 

[Shake_Zulla]

so this is the 02 located under the car around where the front seats are on the exaust line?

Nope thats the downstream one. Upstream is in the engine bay between the head and the bend for the exhaust to start its run to the back. Should be easy to see from underneath the car but you prob will have to take the heat sheild off to see from the top.

 

[stars]

The catalytic convertor is the half way point of reference. There is one in front of the cat and one one the back of the cat. So total there is 2. The one before the cat is called upstream. The one after the cat is called downstream. Use the catalytic convertor as your reference when ordering o2 sensors.

You may have 4 total though, 2 up and 2 down. In that case best to replace them in pairs because if one is going faulty rest assure the other is not far behind.

 

[bullettdsm]

You may have 4 total though, 2 up and 2 down. In that case best to replace them in pairs because if one is going faulty rest assure the other is not far behind.

Why ?

As I was reading your post, I'm thinking very nicely done. Simple descriptor for the OP to understand. Good job.

And then you continue on with a guess. Why? Sometimes less is better. Nobody's 1st or 2nd gen Eclipse on this site is going to have four O2's. So why muddle the issue with a guess?

And OP, the rear O2 sensor will do nothing to affect your problem. It is basically there to check to see if your cat is working.

MB

 

[stars]

I forgot it had only 2 o2 sensor's should have caught that, was thinking about newer vehicles I work on....oops sry

So, bullettdsm, your saying the point of a o2 sensor your saying is to see if the "cat convertor is working"? Are you sure an o2 sensor don't help the ecu adjust for a lean/rich mixtures then? As I read your post it doesn't make any sense either because when information from oxygen sensors is coupled with information from other sources, it can be used to indirectly determine the air-to-fuel ratio. An o2 sensor does not monitor in any way the "cat convertor" itself... o2 sensors are checking the oxygen content passing thru the cat with both sensors. o2 sensors keeps the mixture from getting too rich which is why cats fail, they get plugged up from excessive unmetered/unburned fuel expelled into the exhaust downstream toward the cat. Cat failures are caused by faulty 02 sensors, I always found a bad/faulty o2 sensor may/can damage your cat, and cause problems like; no starts to rough idles then the car stalls. Talk about muddle on about a guess....

 

[starfish]

I forgot it had only 2 o2 sensor's should have caught that, was thinking about newer vehicles I work on....oops sry

So, bullettdsm, your saying the point of a o2 sensor your saying is to see if the "cat convertor is working"? Are you sure an o2 sensor don't help the ecu adjust for a lean/rich mixtures then? As I read your post it doesn't make any sense either because when information from oxygen sensors is coupled with information from other sources, it can be used to indirectly determine the air-to-fuel ratio. An o2 sensor does not monitor in any way the "cat convertor" itself... o2 sensors are checking the oxygen content passing thru the cat with both sensors. o2 sensors keeps the mixture from getting too rich which is why cats fail, they get plugged up from excessive unmetered/unburned fuel expelled into the exhaust downstream toward the cat. Cat failures are caused by faulty 02 sensors, I always found a bad/faulty o2 sensor may/can damage your cat, and cause problems like; no starts to rough idles then the car stalls. Talk about muddle on about a guess....

If you dont think what Bullett is saying makes any sense, I dont Know what to sayHe's got so many stars,you should be saluting him!

 

[bullettdsm]

I forgot it had only 2 o2 sensor's should have caught that, was thinking about newer vehicles I work on....oops sry

So, bullettdsm, your saying the point of a o2 sensor your saying is to see if the "cat convertor is working"? Are you sure an o2 sensor don't help the ecu adjust for a lean/rich mixtures then? As I read your post it doesn't make any sense either because when information from oxygen sensors is coupled with information from other sources, it can be used to indirectly determine the air-to-fuel ratio. An o2 sensor does not monitor in any way the "cat convertor" itself... o2 sensors are checking the oxygen content passing thru the cat with both sensors. o2 sensors keeps the mixture from getting too rich which is why cats fail, they get plugged up from excessive unmetered/unburned fuel expelled into the exhaust downstream toward the cat. Cat failures are caused by faulty 02 sensors, I always found a bad/faulty o2 sensor may/can damage your cat, and cause problems like; no starts to rough idles then the car stalls. Talk about muddle on about a guess....

You need to understand WHICH O2 you are talking about (oh and by the way, angry name calling pm's won't change the facts).

If you were familiar with our cars (which quite obviously you are not), you would know that fuel adjustments are with the FRONT O2 sensor.

I'm not sure where you are getting your attitude from, but I suggest that you check it at the door. I feel that I gave you playful way out of your faux pas in information. {also editted: the line I posted here was a little on the inciteful side. Not my style} (btw, I'm not a moderator. A brilliant mind like yourself should have noticed that)

Edit in; I changed my mind. No need to post the pm.

Op, stick with the info I gave you and think about this; on OUR cars we delete the rear O2 often. We also run with bad O2's. It has zero effect on our starts and our idle etc. Its the front o2 that is changing air fuel mixture via our computer. As you said, the rear O2 is basically "just emissions junk". . It will do nothing to adjust your air fuel mixture.

MB

 

[stars]

I don't understand something:

What kind of "shade tree" mechanic would tell someone "NOT" to replace a part that is defective and throwing a code? Especially, if the part has caused him a driveability problem, why not recommend replacement?

Bullettdsm, I don't know what occupation your in but, remind me to never have you work on my vehicles......


Btw.... I do not come here to kiss ass and make new friends. I come here to give advice out of my own freewill. I do this work for a living everyday; for the past 19 years so, I have nothing to gain or loose, here.

 

[Shake_Zulla]

I don't understand something:

What kind of "shade tree" mechanic would tell someone "NOT" to replace a part that is defective and throwing a code? Especially, if the part has caused him a driveability problem, why not recommend replacement?

Bullettdsm, I don't know what occupation your in but, remind me to never have you work on my vehicles......


Btw.... I do not come here to kiss ass and make new friends. I come here to give advice out of my own freewill. I do this work for a living everyday; for the past 19 years so, I have nothing to gain or lose.

He was simply stating that the upstream o2 sensor is the one that would cause his car to run rough not the downstream o2. Obviously replace anything that is broken but if its throwing that code and runnin rough then its most likley the upstream one. Reguardless you are fighting a battle you cannot win fool.

Mark you can work on my car anytime Even if you don't repair my useless downstream o2 sensor that is only there for OBD2 testing.

 

[Bannery]

Hello everyone!



I apologise because of my English
I was shopping one OBD2 error code reader:
Autel MaxiScan MS300
My car : Mitsubishi Eclipse 1999 420a
Until all of them DATA LINK ERROR mistake I receive a message when I make it connect to the car,
What may be the problem?

 

[bullettdsm]

Bannery please start your own thread for your problem(s).

I am confused with your post.

Is your car not working properly?

MB

 

[Bannery]

Bannery please start your own thread for your problem(s).

I am confused with your post.

Is your car not working properly?

MB

Thank you for your answer,
1, my car work , but he has problems.
2, I would like the mistake to read through,
3, I received it a code scanner,
4,when I join it the my car, this announces it for me the apparatus: Data Link Error
My question the successor:
Eclipse 1999 (420a) + autel maxiscan ms300 compatible?
If not,then offer somebody for me a working code reader to my car.

Thank You

 

[Shake_Zulla]

Thank you for your answer,
1, my car work , but he has problems.
2, I would like the mistake to read through,
3, I received it a code scanner,
4,when I join it the my car, this announces it for me the apparatus: Data Link Error
My question the successor:
Eclipse 1999 (420a) + autel maxiscan ms300 compatible?
If not,then offer somebody for me a working code reader to my car.

Thank You

My answer the successor:
Sounds like your obd2 is not working try this instead...
2GNT.com - PCM_Error_Codes

 

[Bannery]

My answer the successor:
Sounds like your obd2 is not working try this instead...
2GNT.com - PCM_Error_Codes

Thank you for your answer,
this keyed thing , is out of order into my car.
Nothing flashes up,
It i don't understand, that measured get Data Link Error message. if I connect it with my car?
according to me this not compatible device with my car . ( autel maxiscan ms300 )
Somebody say for me one: compatible obd2 reader to my car. Mitsubishi eclipse 1999 (420a)
Thank You

 

[Kslam1981]

Here we go again... P0140 02 sensor circuit no activity detected bank 1 sensor 2 stays constant. Slight miss while idle, will stall out occasionally when coming to stops. P1297 No charge in MAP from start to run. Car would not hold idle unless you drop in neutral and stay on the throttle. Replaced MAP, code cleared, car ran the same as it did before tho.. 2 weeks later I put the old MAP back on the vehicle and it runs the same as it did before it ever had the new MAP.. So, drive it for another few months and run into the same code, P1297, the P0140 is still constant and it would not hold idle at all. Let it sit and start it up and it runs as it did before (driveable).. any help? no I never replaced the rear 02, just the MAP when it went stupid on me several months ago but now have the old MAP back on being it made no difference..

Oh and I nearly forgot.. I also smell fuel the first few minutes of driving

 

[WES_393]

Here we go again... P0140 02 sensor circuit no activity detected bank 1 sensor 2 stays constant. Slight miss while idle, will stall out occasionally when coming to stops. P1297 No charge in MAP from start to run. Car would not hold idle unless you drop in neutral and stay on the throttle. Replaced MAP, code cleared, car ran the same as it did before tho.. 2 weeks later I put the old MAP back on the vehicle and it runs the same as it did before it ever had the new MAP.. So, drive it for another few months and run into the same code, P1297, the P0140 is still constant and it would not hold idle at all. Let it sit and start it up and it runs as it did before (driveable).. any help? no I never replaced the rear 02, just the MAP when it went stupid on me several months ago but now have the old MAP back on being it made no difference..

Oh and I nearly forgot.. I also smell fuel the first few minutes of driving

Like mentioned before in this thread, it wouldn't be a bad idea to replace the front O2 sensor. It sounds to me like your running very rich if you can smell fuel while driving (assuming there are no fuel leaks). Overly rich conditions can make a car sputter and die. The front O2 in these cars is a huge part of controlling the A/F ratio. Why the front O2 going AWOL would set off the rear O2 is strange. Possibly the rear O2 reading overly rich mixture and setting off a CEL? Either way, it wouldn't hurt to throw a new front O2 sensor in there.

Here is a good source for OEM O2 sensors. (Got my Denso for like $80)
OxygenSensors.com

However, if you want to get one from a parts store, just make sure it's NOT a universal one. Many people have had poor luck with these, including myself.
Just as an example: Bosch 13399 - Oxygen Sensor | O'Reilly Auto Parts

 

[Kslam1981]

Swapped the front 02 sensor, do I need to reset the ECU using a OBD2 or anything or just swap and drive? no difference in the miss..

 

[LD25Delta9]

Take off your positive battery lead and touch it to a ground. That should reset the ecu. Start there. Or go to a chain parts store and have them clear the codes with a scan tool.