Too much gas .... O2 sensor clean help

Hello.

My XJ 1999 is consuming a lot of gas.. I already cleaned throotle body with its IAC sensor, Map sensor and TPS sensor... also changed rotor and distribuitor cap, changed spark plugs for the OEM Champion reference brandnew. Changed Air filter.

I have OEM tires size running, no changes in suspension or engine out of the OEM equipment. No faults or error codes on the Check Engine Light, but the XJ is using a lot of gas...

I read somewere in the past that the responsible for manage the gas is the CPU through the signat it receives from the O2 sensors (one pre-catalitic and one post-catalitic convertor) is there a way to clean them up, as I said no error codes showed on the check engine light.

Can somebody tell me if it is possible to clean those O2 sensors and get less gas consuming? How I should clean them? With what kind of cleaner (carburator cleaner or electronic cleaner).

Or any idea how can I improving gas consumption?

Thanks for your help

JorgeA.

I am in the same boat with my '00. How much is "consuming a lot of gas". The xj is basically as aerodynamic brick with a motor designed for torque not gas mileage. I am getting around 250 miles a tank.

oven cleaner will eat the carbon right off. works great

i used to use carb cleaner and let it air dry. dont know if its good for it or not but it would turn off my idiot light on my tercel and somehow made it smoggable for about 2-3 weeks at a time.

Ok.. I did the job today... took apart the two O2 sensors (Upstream and Downstream), cleaned first with a rag, then with Carburator Cleaner, let them dry,then with some electrical cleaner spray on the inside the little holes, then with a electrical rotary dremel with the fiber attachment cleaned the outside of the metal cover.. after I few minutes installed them, conected battery and turn on the engine... the engine runs fine, no hesitation, but at the first minutes I got a smeel like past egg or something like that... after some minutes the smell went out and smell like normal engine gas.... no error codes, no check engine light.....

Taking advantage of the Rotary Tool I took the big filter air box and remove the little esquare or rectangular hole for incomming air, make a double size hole in order to get more air than the original set up....

Now I will go for a ride and let you know how it feels...

Thanks for your help.

JorgeA

How did it go? I too would like to clean my o2 sensors but I have four of them.

I read somewhere, maybe here, that you can tell if your engine is running rich if there is a black ring on the tail pipe (everyone make your own jokes locally).

I checked and yep, there's the ring. I read that the MAP sensor may cause this problem.

My question is this, how do you clean a MAP sensor? Take it of and spray it down with MAP sensor cleaner? I've cleaned my wife's MAP sensor on her Mustang, but that thing is huge comparied to the Jeep.

Before I ruin a $98 sensor I thought I'd ask you guys.

P.S. O2 sensors were changed about a month ago. No real improvement in mpg (12.7 city, 14.7 highway).

Mudderoy said:

I read somewhere, maybe here, that you can tell if your engine is running rich if there is a black ring on the tail pipe (everyone make your own jokes locally).

I checked and yep, there's the ring. I read that the MAP sensor may cause this problem.

My question is this, how do you clean a MAP sensor? Take it of and spray it down with MAP sensor cleaner? I've cleaned my wife's MAP sensor on her Mustang, but that thing is huge comparied to the Jeep.

Before I ruin a $98 sensor I thought I'd ask you guys.

P.S. O2 sensors were changed about a month ago. No real improvement in mpg (12.7 city, 14.7 highway).

Click to expand...

A really bad CTS or IAC (also called an MAT) sensor can be ignored by the ECU and throw the computer into open loop mode, waisting fuel. Jeep MAP sensors are pressure sensors, not Mass Air Flow (MAF) sensors, and the Jeep MAP sensor rarely fails, unlike MAF sensors on other vehicles.

I would look eslewhere, like a dirty air filter, CTS, MAT, non-locking torque converter, or slipping torque converter, old plugs, wires, cap, rotor, worn dizzy, or leaking fuel injectors.

Alternately, since you live around Houston, it could just be parking on the freeway too long with the engine runing.

Also check that the O2 sensors are working, check that the O2 sensor heater is getting 12-14 volts to the heater wire.

Sea-Foam works well to clean the O2 sensors... just put the tips in a cup full of it... come back a little while later and swirl around...

JOe

Ecomike said:

A really bad CTS or IAC (also called an MAT) sensor can be ignored by the ECU and throw the computer into open loop mode, waisting fuel. Jeep MAP sensors are pressure sensors, not Mass Air Flow (MAF) sensors, and the Jeep MAP sensor rarely fails, unlike MAF sensors on other vehicles.

I would look eslewhere, like a dirty air filter, CTS, MAT, non-locking torque converter, or slipping torque converter, old plugs, wires, cap, rotor, worn dizzy, or leaking fuel injectors.

Alternately, since you live around Houston, it could just be parking on the freeway too long with the engine runing.

Also check that the O2 sensors are working, check that the O2 sensor heater is getting 12-14 volts to the heater wire.

Click to expand...

Yep, you are right, I was getting the MAP and MAF confused.

plugs, plug wires, rotor, cap, O2 sensors, injector cleaner (several times).

Oh since I-10 to beltway 8 south is closed, I've been going down Clay to beltway 8. When I was sitting on I-10 the gas mileage was 10.5 mpg!!!

I'll just have to break down and check the voltages on everything.

Also, forgot to mention, I had a vacumn leak months ago. You could hear it, but I could never find it. Eventually the whistling stopped. I might fix my problem just by replacing all the vacumn lines. I see that the MAP has a vacumn line going to it, at least that what I saw in a picture online.

Thanks for the info.