O2 sensors

[laidbackblk45]

Are O2 sensors a problem in the Q45? Has anyone here had to replace them on there Q? I have a 95 with 250k miles and I was wondering if I should be concerned a/b those.

[elwesso]

They arent a problem per se but certainly they will stop working as good as they did new. usually about 60k life expectancy to stay working as new..

It all depends on your standards. Over the course of 60k miles, new o2 sensors will probably pay for themselves in the savings youll see in fuel economy. They can change fuel economy up to 20%, but more like 10% on average (since they only do about 10% each way)

I would recommend replacing them at 250k... many times when O2 sensors fail they give you a code 45, IE injector leak when in fact its just the fact that the o2 sensors dont read accurately.

[qship96]

I just had mine done for the 1st time at 202,000 miles.....zero change in fuel economy,guess the original ones were working fine.Your results may differ,but I would not blindly replace them at 60,90,120,or even 150K without testing or you just may piss a few hundred down the drain.

[Q45tech]

Unfortunately few techs know how to test them precisely. With a Consult you can look at the switching waveform while driving at a steady cruise speed and count the back and forth [voltage swings] below and above 0.5 volts in a 10 second interval..............called cross counts by some.

You can look at the adaptive trim% on each bank which should be 100% +- some small incremnt say 95-105% [this is how far above or below the preprogrammed injector pulse is for the specific load conditions......how much the ecu changes things from brand new to compensate for age wear, etc].

If you think about it 1% [<0.02 milliseconds] at cruise will change the fuel consumption by 1% but maybe 10% might be noticable on a long trip.

O2 sensor are ignored under accelerations and at idle because they cool too quickly to be reliable. Only steady rpm/speed cruise maintains their temperature.

2000 cars get the newer wideband O2 which are accurate at idle and cost $275 each.

If you are using E10 the whole set up is trashed anyway as the extra O2 in gasoline forces the ecu to run 3.8%-5% richer causing a 5% drop in mpg at cruise..............that's 1.0 mpg you lose thanks to E10.

The 1996 being OBD2 is more finicky of O2 sensor sluggishness.

[laidbackblk45]

I have changed them before on other cars and I had not heard anything a/b them being changed on the Q before. I had spoken with someone from T3 (receptionist who answered the phone) about having some work done since I live here in Atlanta and she stated that they very rarely have done an O2 sensor job. I just wanted to cover all the bases on issues that could effect acceleration besides the KS. I will clean the MAF this weekend and use some BG44K also for the first time. I really do love this car and this is the third Infiniti that I have owned and I want to protect my investment.

[maxnix]

Talk to Ty at the Cobb location, not the receptionist.

I guarantee she is not turning wrenches.

[Magnum PI]

Just did the passenger side one this past weekend. Fortunately my buddy had an O2 removal tool, as it is hard to get to and get the proper leverage to loosen it. Thought it might be part of the cause of my intermittent bucking and stalling. But nope. it still runs the same. Havent noticed any improvement yet, but the search for the cause of the more problematic performance issues probably takes away from any positive effect the change might have caused.

In short, if you like to wrench, this is a contortionist's delight. Had to cut the wire to get the tool over the sensor, pull the wire out of a little clip on the back of the engine block and then reinstall. Took about 1 hour. Would have been more fun if it solved a problem.