O2 sensor and MAP sensor replacement

Hi there,

The first thing I would be doing is checking for a vacuum leak, both these codes can be set with with induction air leaks, the links below can help you diagnose this problem.
Mark (mhpautos)


https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor
https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Thank you very much for your quick response and links.

If you still have problems, don’t hesitate to let me know so we can work through the problems.

Have you had a chance to inspect things yet? Here is another link that will be of help:

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

Mark (mhautos)

Good Morning,

No, I have not yet checked it out. It's been pretty cold here. Starting Monday it will be between 50 and mid-60-degree weather. When I was younger the weather did not bother me. I look forward to a day when I can purchase a new vehicle. Buying used most of my life I know I'm going to inherit problems and the previous owners' ability to be honest is a big factor. As soon as I check it out I will let you know. I really appreciate this site. Thank you very much!

Hi,

I noticed it's been a couple of days since we heard from you. Have you made any progress? We are interested in knowing.

Take care and God Bless,

Joe

Well, as I stated In throwing an O2 code and a MAP Sensor code. but I know until I get the exhaust leak fixed there's no point in really changing them. I plan on jacking it up tomorrow crawling under there and trying to see or feel where it's coming from and how major it is. Thanks for looking out.

You are very welcome. Just a thought. If you have an exhaust leak prior to the catalytic converter, it can cause a lean fuel mixture because unmetered air can enter via the leak. Make sure to check around the exhaust manifold.

Let me know if I can help.

Joe

I still didn't have time but I did want to say. the 02 sensor was bank 2 sensor two or down stream too rich. I'm not sure if I used the right terms I don't have my scan tool this moment (445am)l but wouldn't 2 and 2 mean below the converter? Not sure yet but I will let you know. I do know it seems to be flooding out and/or cutting out when I slow down while driving or coming to a stop.. Plus every time I work on any vehicle one of several neighbors comes out and distracts me by striking up long conversations. It's very hard to get anything done without being rude.. Thanks for your reply!

Hi,

If it is sensor 2, then you are correct. It will be after the converter. If it is running rich, check to make sure the fuel pressure is within spec. If it is, then we will need to check the coolant temp sensor as well as the injectors.

Here is a link that shows how fuel pressure it checked:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Also, here are the fuel pressure specs:

2004 Jeep Truck Liberty 4WD V6-3.7L VIN K
Pressure, Vacuum and Temperature
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Fuel Pressure Specifications Pressure, Vacuum and Temperature
PRESSURE, VACUUM AND TEMPERATURE
FUEL SYSTEM PRESSURE
If equipped with JTEC Powertrain Control Module using 3 electrical connectors: 339 kPa ± 34 kPa (49.2 psi ± 2 psi)
If equipped with NGC Powertrain Control Module using 4 electrical connectors: 400 kPa ± 34 kPa (58 psi ± 5 psi)

Let me know what you find or if you have other questions.

Take care,

Joe

I was wrong. I had a lot going on the past week and was exhausted. So I crawled under this morning and low and be hold there is no catalytic converter. He ran flex pipe up to the front from where converter should have been and there is a leak towards manifold and there is one towards the back before or after the muffler. I do not think it has anything to do with the exhaust though. It has to be something else making it run too lean not rich as I had said at 4:45 am sorry about that. I know previous owner had replaced a manifold gasket and supposedly valve cover gaskets. It wants to stall out only after its warmed up after I've been driving for awhile. It starts right up in the morning with no problem. I'm thinking to start simple. Check air filter, spark plugs etc. I don't know. I got a quote for an exhaust front to back and it was over $1,000.00. $1,025.00 to be exact. The exhaust can wait. They didn't even want to consider a universal converter. I bought a $1,500.00 car because that's all I could afford at the time. If I had an extra $1,000.00 I would have bought a $2,500.00 car. I just do not know where to begin but you all have been very helpful. Until I figure it out I will have one foot on the brake and one on the gas when at a stop sign or red light. Thanks for everything.

Codes I'm getting . P0108 Manifold Pressure Sensor Barametric Pressure Circuit High and P0158 02 Sensor Circuit High Voltage Bank 2 Sensor 2 if that helps. I wrote them down word for word. Thanks

Hi,

The idea that they are both high voltage codes could indicate a short. Have you checked the wiring and the connectors? There could be damage or a short. Also, disconnect the connectors and check for corrosion or a damaged pin in the connector or sensor.

Joe

Thank you so much. I was going to clean the MAP sensor so. I will definitely check that out. Also I noticed I can see that 02 Sensor and I don't think I'm supposed to be able to see it clear as day it looks like maybe someone just wired it in and clamped or attached it right there. Thanks to you guys I'm getting closer. Unfortunately it's dark here now. Tomorrow is another day. Ill try to remember to take a few pics. Also my muffler and tailpipe are fine. I inspected them. I'm thinking the leaks are either in the clamps or someplace on the flex pipe or closer to manifold I'll know more tomorrow. Have a great night.

Hi,

You are very welcome. Let me know what you find or if you have other questions.

Take care and let me know what you find.

Joe

Well, I didn't get much done today but I did check the entire exhaust out. I'm pretty sure the O2 sensor is not supposed to be just hanging there and it's rough looking. Two pieces of flex pipe a few holes by the clamps. The rest of the old pipes going to muffler, the muffler itself and the tail pipe are fine. I have an O2 sensor I have a new MAP Sensor I'm going to get the left and right front pipes and a converter online for around $300 New.. I am up loading a pic of that O2 sensor because I know its not supposed to look like that and out in the wide open like that I'm not sure but it doesn't look good to me. I checked the hose by map sensor for leaks. That sensor looks raggedy also. Ok I sure hope I'm on the right track. Maybe I can pay my brother to put that exhaust together once I get parts.

I think I will just do it right and get Driver side Converter and passenger side and the Y pipe as long as muffler and tail pipe are good. NYS I need to pass emissions. This is inspected until the end of October but if it's going to get done I might as well do it right. And that O2 sensor has been hanging there in the rain and snow and wow I'm glad with your help I was able to find all this so it can get taken care of. Thanks again.

Hi,

The o2 sensor is bolted into the exhaust and will be exposed as in the pic. However, it looks like it may have been welded on the one side. If it is, that's going to be a problem because you won't be able to remove it.

Let me know.
Joe

Wow, okay, thanks. Maybe it's a good idea to get the new exhaust parts then.

Honestly, I would recommend it. From what I can tell, someone used a generic type flex tubing to repair behind the sensor. It's really hard for me to tell simply because I'm not there.

I understand. Thank you so much. This time buying I took someone with me. They test drove it I test drove it. It was winter It was running when I got there. I was told he had just changed valve cover gaskets and that the exhaust had a leak someplace. I never would have suspected there was flex pipe and no catalytic converter. Well two on this vehicle. My mom had a 2004 Renegade and other than poor fuel economy she never had a problem. I have since read about all if the recalls on it. I have noticed in my 57 years that nearly all makes and models have their own issues. Thanks a ton.

You are very welcome. Let me know if there is anything I can do to help.

Take care,
Joe

Oh boy. I finally went out to at least find and clean MAP Sensor I can't believe what I found. I'm adding pics. Now what. I can't even get old one out before dark to replace it and I have to drive 4 miles one way and back in the am. I promised a State Cop I'd sit with her dad while she goes to church. I don't know her but we have a mutual friend who asked me and there is no one else to go out there. Will driving 8 miles hurt this? I think that is the MAP Sensor. I finally got a repair book for this.

Hi,

It won't run properly, but it shouldn't really hurt anything. Try to clean it up as best you can.

Let me know what I can do to help.

JOe

Well, it took about 2 hours to get the one half of broken sensor out of the harness and to use an 8mm hand wrench to turn the 2 tiny bolts holding the other half of MAP sensor 1/4 turn at a time. I was ready to scream. Now tomorrow I'll just put the new one in. Yeah, hopefully the bolts will go in quicker than they came out. Thanks so much.

Hi,

You're very welcome. They can be a pain. LOL Regardless, let me know how things turn out for you and it takes care of the problem.

Joe

Okay, so 6 hours later the new MAP sensor is in. Both the Map sensor and O2 sensor codes are gone and the check engine light is off. I will clean that new MAP sensor every so often because I don't ever want to have to work in that tight of a space again, Lol. Thank you for all of your support and answering my questions. Glad I changed the MAP Sensor before the O2 sensor because the one took care of both. I guess things aren't always what they seem to be and that's why you are a mechanic and I'm not. Hope you have a great day!

Hi,

You are very welcome and you did a good job. Please feel free to come back if you ever need anything in the future. You're always welcome here.

Take care and God Bless,
Joe

I took it for a long ride. That gas fume smell on the inside is gone. It's idling smooth. My RPMs are back on point when it goes through the gears. No stalling no hesitation. What a difference. Oh, I did find another issue. The valve cover gasket on passenger side is leaking oil. I never would have noticed but it sat for 2 days while I was trying to change MAP sensor without taking belt and A/C compressor and all of that off. So in hindsight I'm glad It took about 8 hours to remove and replace those bolts. I did find a video on a 2005 Liberty passenger side valve cover gasket replacement. Mechanics make it look so easy. My friend's dad is a mechanic and he will be in this weekend and he offered to do it because there's a lot to remove and I don't want to break the hardened hoses. 17 years many parts dry out and get brittle. Thanks so much. You must get overwhelmed with questions but you take the time to answer. This is my go to site because you don't have pretend "I play one on tv" mechanics thinking they have all the answers. God Bless and take care.

Hi,

If you need, start a new thread for the valve cover gasket replacement. It's no problem. Also, you are very welcome and I'm glad to hear you'll be back. Please feel free to come back anytime.

Take good care of yourself.

Joe

Thanks so much. I took you up on the offer and started a new thread.

I'll look for it.

Take care,
Joe

Okay, so I bought the two catalytic converters tailpipe and muffler. The y pipe is okay because the estimate I got at a local shop just had the converters tailpipe and muffler listed in their estimate. I found and bought the exact part numbers and am having that put on hopefully tomorrow after the powers steering pump is finished. Today it was front and rear brakes and power steering pump. I left replies for that on one of my questions about tires feel funny.and my power steering question. Along with a gouged rotor and brakes put on backwards. I know this guy buys and sells cars all day long but I don't think he should be because who puts brakes on inside out or backwards and that rotor had a huge gouge on the inside. Well at least with all repairs it should last a few years with maintenance.

Hi,

I have no idea how the brakes were put on backward. Ugh!!! That means the steel backing plate on the brake pad was stopping you. No wonder the rotor was bad.

Let me know how everything turns out for you. I'm really interested in knowing.

Take care and thanks for the update.

Joe

Thanks at least it's all getting done. And done correctly. I'll post pics of my new exhaust. I did get a new O2 sensor the other one was welded to the flex pipe. Yeah, I had to get a new pulley as you can see the other one needs replaced in the pic and yeah that rotor. I knew there was something I just couldn't put my finger on. My brake pedal didn't feel right. I was going to bleed them then that rotor was found. Thanks for everything.

Wow! That looks rough.

Let me know how things turn out for you.

Joe