I felt that this was threadworthy...I've been analyzing data from Torque Pro on my Android phone, connected to my Jeep's OBDII via a Bluetooth adapter I got for Christmas. After running tests, I got these cryptic results. I've also noticed just lately that my gas mileage is in the toilet. I don't have exact numbers, but I can practically watch the gauge drop after a half hour drive or so. No CEL or other trouble codes.



I found this thread which has been the most helpful so far. It appears the failed test references the upstream oxygen sensor. It all seems to make sense, but some other Google results have shown that people have replaced their sensors (on different vehicles) and still have a failed result.

I was wondering if any of you wizards out there are familiar with this at all or might have encountered it. I'm going to go ahead and order the O2 sensors because I have no idea when (if ever) they were replaced.

Other things worth noting:

-Full tuneup was done last Spring consisting of new NGK plugs, NAPA wires, NAPA cap & rotor, and new air filter.
-Temp sensor functioning correctly, reading around 199* and no higher than 205* typically.
-Brand new fuel pump and filter installed two weeks ago.
-Rebuilt 703 injectors installed a few weeks ago.

The Jeep runs excellent otherwise, but it does have a very slight stumble/misfire condition at idle. This was also present before the injector upgrade. Could this be caused by a rich fuel mixture? Exhaust seems normal and does not have any rich fuel smell to it.

 

This should be interesting

 

So since all these results are pointing fingers at the upstream sensor, I'm going to go ahead and order one from Rock Auto.

Everyone with a smartphone and OBDII XJ's should buy this app, and the Bluetooth adapter. Total of like $25, worth every penny.

 

Sound like I need to get one.

 

Yeah I want to get that program. It looks neat. Can you leave it on the connector all the time, while driving etc? Or should you remove it before driving? Wondering how much data you can retrieve if it connects long term.

 

You can leave it connected for real time logging while driving. It's a really cool app and definitely worth the money. I'd buy it if i had an OBDII XJ.

 

Extremely cool app and totally worth every penny for the full version and BT adapter. Had one for around 1.5 years or so. For the money it can't be beat.

 

If you want to leave it connected you should get one with and on/off switch, it will stay on when you turn off the Jeep. The draw is small but it is still a drain on the battery.
Having said that I have left mine connected for days without there being a problem.

 

Agreed, I have had it for the last year or so. It has just diagnosed a faulty trans solenoid too. Now all I need to do is determine what all the realtime figures mean. I don't have any to compare my results to.

 

I don't believe this to be true. From my understanding, the OBDII connector only comes alive if you turn the ignition switch to Run. It will not broadcast data to your phone if the Jeep is off. My particular adapter has LED indicator lights on it, and they are on whenever it is active, which is only from the run position on the switch or while running.

There's an amazing amount of data it can pull from the ECU. Way more data than I would've imagined, most of it useless to me at this point, but definitely handy when there's a problem associated with it.

 

If it helps you at all, I remember seeing some values that were like this when I was playing with my reader. I don't remember which they were, I just chocked it up to being a glitch and forgot about it. I'm also throwing a code for a bad upstream o2 sensor... rather, high voltage... I have new ones in the mail, and I'll let you know what mine read after throwing them in.

 

Pin 16 on the DLC is hot off the battery bus. Power goes through fuse 17 in the PDC. It also powers the headlamp switch.

 

in my 96, the LED on the bluetooth adapter always stays on. I leave it plugged in anyway... and I frequently drive the Jeep only once a week.

 

Thanks for that info! Very interesting. Perhaps the adapter only turns on when it sees a connection from the ECU.

I'll have to double check mine, maybe there is a led that's just dim...but same here, mine isn't my DD. Haven't had a problem with it.

 

Just a little update...here is a screenshot of the live graph of the upstream sensor. Not sure what it means, but when I run the "test", it still fails. I have the new sensor, but I won't be putting it in until later this week.