Oxygen Sensor

[Spike3]

I've read in another XJ forum that some members recommend replacing the oxygen sensor every 60-80k. I'm wondering what you all do with your oxygen sensors. Do you replace them only when the engine starts running oddly or on a regular basis?
The reason I'm asking is because in a recent trip on all highway I got 13.5L/100km (17-18 mpg) and I'm thinking maybe a new sensor would improve that. I found a Denso OEM sensor on rockauto.com for $45 all in. Since I have a 93 I only need one, and any mileage increase will pay off overtime. If I find that out didn't improve then that just means I have a second sensor in case I need it later which isn't a bad worst case scenario.
I have 31" tires and 3.5" lift I'm pretty sure (Jenssen will know for sure) so the other question is if the mileage seems high for my rig. I grew up with relatively new and efficient sedans so I'm not used to this amount of "thirst".

Thanks,
Spike

[4.3LXJ]

Yes, they should be replaced regularly about every 50K

[Spike3]

Yes, they should be replaced regularly about every 50K

Thanks! I'll put the order through then. Should I get the Bosch or Denso one? Or does it really matter?

Bosch: http://www.rockauto.com/catalog/moreinfo.php?pk=279834&cc=1180178
Denso: http://www.rockauto.com/catalog/moreinfo.php?pk=991702&cc=1180178

[nickyg]

I'm not sure which ones are better, but I went with the bosh from rockauto. about 4 months ago..No problems yet..

[4.3LXJ]

I think the Bosch is a better sensor

[Carves]

Denso is normally good stuff.

Rumour has it that the stock sensors in later models were supplied by NTK which rockauto also sells.

Me ... I'm waiting to see how long the mystery ones in a Standard Motor Products red box last .. :D

50 - 80 thou seems to be the common, preferred, change time.

[ParadiseXJ]

17-18 mpg
I have 31" tires and 3.5" lift .
I grew up with relatively new and efficient sedans so I'm not used to this amount of "thirst".




I think this is decent mileage for an XJ especially equipped as you have it. Did you re-calibrate your speed-o gear for the larger tires? If not, you're actually getting more like 19.8 MPG...which is good IMHO.

It is not a sedan, nor is an XJ considered fuel efficient. It is a "truck" shaped like a brick (not really aerodynamic). You'll never get 25-30 MPG in a Jeep...unless it's a Patriot!

[nickxj94]

Bosch sucks on everything they make! Buy one from the dealer they last longer.

[Spike3]

I think this is decent mileage for an XJ especially equipped as you have it. Did you re-calibrate your speed-o gear for the larger tires? If not, you're actually getting more like 19.8 MPG...which is good IMHO.

It is not a sedan, nor is an XJ considered fuel efficient. It is a "truck" shaped like a brick (not really aerodynamic). You'll never get 25-30 MPG in a Jeep...unless it's a Patriot!

How would I do that? Pin it at a given speed and use a radar gun or is there a dial or something to change the readings?

[XjJeepacorn]

I only change mine when the engine light tells me to! Why fix it if it ain't broken? Also haven't really paid attention to how many km I've gone berfor it tells me so!

Sent from my SGH-M919V using Tapatalk

[ParadiseXJ]

How would I do that? Pin it at a given speed and use a radar gun or is there a dial or something to change the readings?

I know this link is for wranglers, but the T/C is essentially the same. Your Jeep probably came from the factory with 225/65/15 tires. Putting larger tires on it changes the rotation of the wheels, axles, transfer case and transmission. Look at the chart on the link and match it up to what it had from the factory and to what it has now. The tooth count on the speedo gear is different. Changing it to the proper one will adjust your speedo and odometer to correct for the new tire size...

http://www.wranglerforum.com/f210/speedo-gear-swap-change-121033.html

This, OR you could just drive a distance...really only 10 miles or so and use a GPS or even highway mile markers and compare it to your odometer. If you drive 10 miles (by the GPS or mile markers, not the odo) and the odometer reads only 9 miles, you'll know your speedometer and odometer is off by 10% So 250 miles is actually 275 miles.

Anyhoo, worth looking into

[Spike3]

I know this link is for wranglers, but the T/C is essentially the same. Your Jeep probably came from the factory with 225/65/15 tires. Putting larger tires on it changes the rotation of the wheels, axles, transfer case and transmission. Look at the chart on the link and match it up to what it had from the factory and to what it has now. The tooth count on the speedo gear is different. Changing it to the proper one will adjust your speedo and odometer to correct for the new tire size...

http://www.wranglerforum.com/f210/speedo-gear-swap-change-121033.html

This, OR you could just drive a distance...really only 10 miles or so and use a GPS or even highway mile markers and compare it to your odometer. If you drive 10 miles (by the GPS or mile markers, not the odo) and the odometer reads only 9 miles, you'll know your speedometer and odometer is off by 10% So 250 miles is actually 275 miles.

Anyhoo, worth looking into

I ran the calculations and the true speed is 12.7% more than the speedometer reading with 31" tires and 3.55:1 differential, compared to the stock specs you've listed.

Edit: I looked up the speedometer gear and they're about $45 so I'll just make a spreadsheet with common speed limits and their corresponding read values. 2 cents to print and tape up, so pretty good savings.

[JENSSEN]

The Jeep in question originally (spikes) originally was fitted with 3:07 gear ratio (5 SPD truck)axles stock with stock tires;when it was reworked at around 500,000kms I used new auto diff's 3:55 added the lift and 31's. Rough calculations said a 31.8" talk tire would be close to the original gear ratio with the smaller tires.

[ParadiseXJ]

I ran the calculations and the true speed is 12.7% more than the speedometer reading with 31" tires and 3.55:1 differential, compared to the stock specs you've listed.

Edit: I looked up the speedometer gear and they're about $45 so I'll just make a spreadsheet with common speed limits and their corresponding read values. 2 cents to print and tape up, so pretty good savings.

That'll work too as long as YOU know your speed and mpg. I ran my MJ with 31" tires with no speedo correction, and figured my mileage...and speed accordingly. I left it like that for a couple years. But the truck has 3.07 gears (D44/d30) so it was rather doggy, so I now have 235's on there.


The Jeep in question originally (spikes) originally was fitted with 3:07 gear ratio (5 SPD truck)axles stock with stock tires;when it was reworked at around 500,000kms I used new auto diff's 3:55 added the lift and 31's. Rough calculations said a 31.8" talk tire would be close to the original gear ratio with the smaller tires.

Currently I have 3.07 gears, 235/75/15's AW4 and 231J. It's still going to be doggy on steep hills till I can get some 4.10's under it, but it runs about 2100 RPM's at 70. Get about 19-20 mpg on long trips.