Help diagnose

[sjx40250]

If you replace the TPS, you might as well clean the TB as well.

 

[logdog]

Get a 195* thermostat from the dealer. It does make a difference.

 

[marcusguy]

Well, the check engine light finally came back on today and I happened to be close to an Autozone. The code was p0138, which says the voltage is too high for the second o2 sensor. That just means it's bad, right? I replaced the first sensor already, but it looks like the second one is the problem.

Marcus

 

[slujeeper5]

Marcusguy,
Hey I hope you figure out whats up! My 98 seems to be doing the same thing, the stumbly idle, the check engine light, and also, it shows the 2.3 when i do that check. Do you have any advice? it is supposed to go in the shop tommorow morning to be looked at, but if i can maybe do it myself, thatd be cool. Did you replace the tps? because someone recently told me that the code 2.3 has to do with the intake air temperature sensor somethin or other. im not sure. advice?

 

[marcusguy]

Stupid o2 sensor is jammed pretty well. I've rounded it off pretty well and have now bent my pipe wrench by using a cheater bar on it. It just won't break loose. I've been spraying wd-40 on and I let it heat up to normal temps but still can't break it loose. I'm stuck.

marcus

 

[jneary]

if you can get acetalene torch on the convertor, you can heat the threaded part. that will expand the threaded housing and the sensor will loosen.

 

[Northern Pride]

I had the same problem recently, dry weather rough start then a little black smoke then it would smooth out. Changed down stream O2 sensor on Cat and problem solved.


Then wouldn't start in the rain. Found out it was a known issue with XJs replaced the crank sensor and starts in the rain every time.

If you go to an Autozone they will put it on computer for free, and it will tell you O2 sensor but it will not tell you upsteam or down stream.

98 XJ Sport

http://photobucket.com/albums/v458/NorthernPride24241/

 

[ayoikawa]

having similer issue here but I'm not having the heating issue yet (even though I have toreplace radiator and swap to 92 after setting. ) I was driving, when slowing down (turning) engine died, and when I'm in light stopping, it died, and when I stop and started again it died,
I got the TPS and O2 sensor to replace and and see how this will effect, mine is 89 xj limited 180,000miles, those 2 sensors I haven't replaced yet, (and thanks god til wed I'm on vacation,,) so I'm suspecting both since idle is really low as well, (it is between 0 and first line used to be above that as far as I recall)
if anyone has any suggestions let me know this is always my first place to search and get help and learning lot form all of you here.

 

[slujeeper5]

Well, I took mine into the dealership this morning, and they just called me and said the problem was due to my " intake air controller" being bad. They said it would cause the low/rough idle because the engine was not getting the right amount of air and it would cause it to run inefficiently. I guess it reports the amount of air going to the intake manifold and reports that to the computer, and in my case was saying that there was more air than there actually was accounting for the poor fuel mileage too. if there wasnt enough air, it would run rich and some of the gas would be expelled into the exhaust. Well, i guess that makes sense. Im glad i bought that warranty. any thoughts?

 

[ayoikawa]

so far I just replaced the TPS since exhaust was to hot still for me t change, and I had to go out again, but so far without stolling, eventhough idle is go between o to 250 on the gauge. I'll try that sensor as well, since it needs to be replaces(since I have no record of the what previous owner did. and not being changed probably) I'll post the result in here.

 

[ayoikawa]

update on my case, I did do the blow by quick fix (changing OEM parts t new one) 6 month ago, and I took a look at the throttle body this morning to check since lot of people mentioned to have TB cleaned, yes that's where seems to be the issue, lot of gunk on there, so I cleaned that up, start the engine, bam! idle speed is back to normal...... and now I have o2 sensor ready if that fails..

 

[ayoikawa]

well opposite from my last reply, I drove half of the day gone fishing etc. on the way back idle is back to almost line above 0 in idle.... I did clean the IAC this morning see what happens... I have feeling that I have to pull out the TP and clean it good............... and this is my last day of vacation... sucks...

 

[marcusguy]

Here's my update:

Replaced the second o2 sensor and everything seemed great. Filled it up and drove to Mt Whitney. At a half tank we had 210 miles (240 is my best ever, years ago) and in the end I went 300miles (including about 10 offroad) and still had about 1/3 a tank left. Before, with fwy driving, the fuel light would come on at about 220 miles and I would run out by about 250-260 miles.

We climbed whitney and when we started home, I noticed that the idle was MUCH worse than it had ever been before. It was only stumbling, and never stabilizing, instead of before when it was pretty stable but would stumble 1 time every 5-10 seconds. We filled up and at a half tank I had 140 miles, like before I replaced sensors, and the fuel light popped on at 240 miles.

What happened? Did my sensor go bad? No lights have been tripped yet, I guess I will have to wait until they are.

Marcus

 

[Handlebars]

I finally tracked down why I kept getting a P0138 on my '97. Several months ago the rear O2 sensor got tangled up in the rear driveshaft. This pulled the wire harness apart at the connector. I replaced the sensor and spliced the wires back together but kept getting that code, as well as one for the front sensor. I turned out that there is a fuse that supplies power to the front and rear O2 sensor heaters in the engine bay fuse block. I replaced this fuse and all is well, finally.

Check for a blown fuse (#23 I think), if it is blown, check for bare wires that are touching metal on both of the sensors. HTH.