Sporadic O2

[gsxjoe]

I have weird problem, last week after I got home from work, my car started to bog down at idle; no CEL's or anything so I figured it was probably a leak and I would take a look at it in the morning. Well, morning came I it took me about 30 minutes to try and start the car(during which there was a massive backfire.) Finally got her started and she would bog down again, but this time she threw a code for the CTS. So I ordered one and I installed it, added some new coolant and she started right up. After getting t0 180 degrees the car started to get a little mini surge. BLT time, no leaks, checked all the vacuum connections, all good there too.

Usually when I make any changes to my engine I make a log, probably don't need to, but I do. This is where I'm stumped, the O2 will cycle normally, then it will bounce back and forth rapidly. I did a search on the forums and didn't really find any information about a sporadic O2 reading, only O2's that didn't work at all.

I have a attached a log, it's just a rough street tune until I can get this problem resolved and taken to my local shop for a proper tune.

Hopefully this time I don't make an ass of myself and overlook something simple and thanks in advance for any help!

Edit*I just realized that I might have posted this in the wrong section.

 

[Dsmkauai]

Im assuming this is regarding your Mtxl sensor? If so I had the same problem with mine but was because I used 110 leaded gas. Any way sounds like yor sensor is on its way out. The way I fixed mine was getting a new sensor. But first I would check the wiring and also do a open air recalibration.

 

[gsxjoe]

I have not had the chance to wire in the MTXL into my ECU yet, was still in the process of fixing some of the other wiring in the engine bay before I moved to inside the car. The oxygen sensor is fairly new, maybe 500 miles on it(not that it really matters since they can fail at 2 miles or 2000 miles etc) There is a crack on the insulation around the red conductor right at the base of the connector, engine harness side that I wrapped with electrical tape just to prevent that wire from grounding out. I was hoping to not have to buy another O2, but I will give that a shot and see what happens.

 

[Dsmkauai]

Hmm try the open air calibration first bro, that may clear things up. Also since you say a wire got exposed its possible it shorted something out before you caught it. I would check things over good before spending the $85 for a new sensor. Got any friends running a wideband with the same Bosch sensor, maye you can borrow one just to check if a new sensor solves the problem.

 

[gsxjoe]

My wideband sensor is fine(it's been calibrated), it is not currently being logged, so the log that I posted is from the O2 coming off the O2 housing. I just ordered a new one and will be putting it in tonight to try and clear up the problem. If it doesn't work then I will probably have to try and find a way to fix the wires on the harness or splice in a new connector(if I can find one that is)


Bah! electrical problems are the worst

Just replaced the O2, it smoothed everything out a little, but not much, idles like crap. I have the idle set to 900, and it bounces around between 800 and 950. Vacuum drops as well. I really am clueless as to what could be going on. The only thing that I have done since I had it running again was replace the fuel injector connectors, I used heat shrink with glue and soldered all the connections as well as heat shrink on the heat shrink, then more heat shrink to hold it all together to the connectors.

I did notice that the rubber insert piece that holds the wires into the O2 connector, harness side, was popping out a little. I did push it back in and make sure there was no bare wire showing.

Also, I checked all the vacuum hoses and connections and they seem to be in good order, all secure and no holes. I am going to do another BLT to make sure I didn't miss anything the first time around. (Using a compressor, )