New 02 Sensors = Mileage Increase

[MTBGUY]

The universal 2 bolt design in the aftermarket gives you the ability to use a standard 18x150 metric O2 sensor in the flange. I used this type in my turbo 4R for years, swapping several different bosch turbo applications into that boss plate.

If it worked for 200 miles and you got the code, reread my rant above. Before I bought the 'real thing' I'd sure make sure you don't have another problem causing the code. You can test O2 sensors with a MM and the same torch you used to remove the old sensor.

Scott Justusson

Thanks Scott- The car runs and idles fine either way (with the CEL code on or off). For the brief period of time before I got the CEL again, the truck seemed much peppier- now it seems slow and sluglike again. I think it may be the CATS themselves- a local exhaust place looked at the entire exhaust with a "sniffer tool" and could not detect any leaks.

They said they could weld in a large single cat for about $230, just not sure if its legal or not.

 

[scottm]

The CEL codes I had with the old and the universal sensors were apparently heater failures. It was only a problem when cold and/or idling, when exhaust temps aren't high enough. Bosch, and maybe everyone, switched to ceramic heaters since my '97 was designed. I'm suspicious those heaters use a different amount of power, and I suspect the amount of current flow might be the internal test that was failing and throwing the CEL. The aftermarket "OE" sensors may be more suitable than the universal sensors I tried, but they get close to cDan's price.

 

[SUMOTOY]

The CEL codes I had with the old and the universal sensors were apparently heater failures. It was only a problem when cold and/or idling, when exhaust temps aren't high enough. Bosch, and maybe everyone, switched to ceramic heaters since my '97 was designed. I'm suspicious those heaters use a different amount of power, and I suspect the amount of current flow might be the internal test that was failing and throwing the CEL. The aftermarket "OE" sensors may be more suitable than the universal sensors I tried, but they get close to cDan's price.

Could be... Depends on what they sold you. The later "Planar" style O2 sensors use a 12-15ohm heater resistance thru the ECM ground circuit. The early "Thimble" style (and what came with the truck) has 2-6.5ohm heater resistance thru the ECM ground.

The easy way to tell the difference between a Thimble and Planar style O2, is to look at the sampling tip. The Thimble style has slots on the sides of the probe and the tip is closed. The Planar style has no slots on the side of the probe and the tip is open (where it samples from).

I'd suspect that it's possible the universal fitment O2 maybe calling for a Planar style O2, which could throw a heater element code in an OBD II 80.

My preference is the Planar Style if the computer will accept it, it's a better O2 sensor in terms of life and sampling. It might also be interesting to find out of the pre OBDII 80's can use the Planar style without issues.

Scott Justusson

 

[scottm]

The easy way to tell the difference between a Thimble and Planar style O2, is to look at the sampling tip. The Thimble style has slots on the sides of the probe and the tip is closed. The Planar style has no slots on the side of the probe and the tip is open (where it samples from).

Can you tell by the pics I posted earlier in this thread? Guys seem to be having better luck with OE style aftermarket replacements, pics I've seen look more like the original style.

 

[SUMOTOY]

Can you tell by the pics I posted earlier in this thread? Guys seem to be having better luck with OE style aftermarket replacements, pics I've seen look more like the original style.

The 15728 you show is also what my Bosch electronic cat shows for the universal application, though the sensor 'looks like' it's a Planar style sensor (double cone tip sampling - no slots on side of probe - computer looking for 12-15ohms resistance). The OE (with connector) fitment shows 13422, which appears to be the Thimble style (slots on the side like the original - 2-6.5ohms). The pre OBD II trucks show a OE of 13081 as OE (looks the same as 13422 + adding a locating clip), and no universal.

My opinion? They got this backwards in the catalog. The universal Planar type usually can be used in pre OBD II cars, because there is no feedback loop for O2 heater. The Planar type *Can not* be used in an non Planar app OBDII car because there is a feedback loop for the 02 heater.

I'll get in touch with my Bosch guy and get some confirmation of this. I also suspect a lot of universal 02's will get a bad rap if suppliers are specifying Planar type 02's with OBD II applications that weren't designed for them.

In the meantime, if ordering a bosch 02 for an OBDII 80, I'd order the oe (with harness) application = 13422, since it's the Thimble type that came with the truck.

HTH

Scott Justusson

 

[scottm]

Aftermarket OE are apparently over $90, sometimes well over. cDan's price for OEM originals was just over $100, so I wouldn't bother with OE aftermarket. It was exciting trying to beat "the Man" and save a buck, but in the end it's wise to feed the cDogs and avoid the cHex.

 

[SUMOTOY]

Aftermarket OE are apparently over $90, sometimes well over. cDan's price for OEM originals was just over $100, so I wouldn't bother with OE aftermarket. It was exciting trying to beat "the Man" and save a buck, but in the end it's wise to feed the cDogs and avoid the cHex.

Tough to compete with Dan in service or price. Add fitment too, it's tough kick the Man. Though I do hold the opinion that the Planar type oxygen sensor is the preferred of the two, which appears to be really a good thing for us pre-OBD II 80 owners. Especially those with forced induction.

SJ

 

[MTBGUY]

I went back and "re-did" everything for lack of a better term (mine were universal splice-in Densos). All the splices were good, it turns out the problem apparently was that when the local muffler place did some exhaust work to replace a stripped out stud, they re-used the old worn-out gasket, and did not tighten the stud bolts down (finger tight only).

I bought two new O2 sensor gaskets (for front and rear), and torqued everything down pretty tight.

No CEL codes now for a few tanks/weeks of driving. Car seems peppier.

My MPG were about 11 city/ 14 hwy during the CODE 420 time period. Now its back up to the original 13 city/16.5 hwy that I used to get before the old ones went slowly bad.

I'll keep the fingers crossed for the time being that I don't see a return of the code. If I get it again I'm replacing both front and rear the same day with factory original replacements from Cdan. I wasted a lot of time on this one!

 

[80ShtnRstrTails]

O2 or not to O2

to all the FJ80's out there. I am new to the forum and relativaly new to the 80's. I've done plenty of trail riding with LC's in the past, and rigg building on 40's. My ? is, has any one investigated the use of O2 simulators, like I have on my Chevy 350 vortec. Now my head about exploded and my eye's , after following that thread from the beging, so forgive me if someone already possed the ?

 

[MTBGUY]

My ? is, has any one investigated the use of O2 simulators, like I have on my Chevy 350 vortec. Now my head about exploded and my eye's , after following that thread from the beging, so forgive me if someone already possed the ?[/quote]

If its the same thing that others call a CEL eliminator (with wires that get spliced inline before the rear O2 sensor) then I believe the consensus (on a related thread) was to just get the cause of the problem fixed.

It seems that the computer is sensitive to /intolerant of aftermarket sensors. I also think Scott/SUMOTOY may be right in his analysis of the thimble/planar sensitivity.

I thought mine was finally fixed because it ran for several weeks without the PO420 code, but the CEL code is back as of this morning.

Thats what I get for posting so soon about it.........

 

[scottm]

Bummer, Rick. I only attempted the aftermarket route because I figured I could get my $ back at Autozone if it didn't work. I did. I'm out just a little time & effort, and hopefully I'm a little wiser.

Dave (or Jan), the front sensor on mine is what the engine management computer uses to trim fuel mix. It'll go into a failsafe, pre-programmed fuel trimming mode if it loses that sensor. I'd think a simulator would give you worse performance than failsafe, if the computer is still using the simulator output and assuming it's real.

 

[jhfj80]

which is better?

so i went to oxygensensors.com and i see densos and walkers. anyone know if there is a quality difference between the 2?

 

[Biff]

Okay so I finally changed my two o2 sensors, was looking forward to the mileage increase I heard on this thread. Well after three full tanks from the same gas station, my mileage has gone from down from 13.5 to 12.1 mpg The rig is exactly the same as when it had the old sensors. I'm thinking I did something wrong, what say you.

 

[schlopecki]

Okay so I finally changed my two o2 sensors, was looking forward to the mileage increase I heard on this thread. Well after three full tanks from the same gas station, my mileage has gone from down from 13.5 to 12.1 mpg The rig is exactly the same as when it had the old sensors. I'm thinking I did something wrong, what say you.

Did you reset the ECU after changing those sensors?

 

[Biff]

Did you reset the ECU after changing those sensors?

No I did not I'm an idiot. I can reset the ecu by removing the efi fuse right?

 

[schlopecki]

No I did not I'm an idiot. I can reset the ecu by removing the efi fuse right?

Yep remove and wait few minutes or unplug battery and wait even longer.
I'm not sure if it will help, but I know that when you mess with such stuff it's the last step to do.
Good luck!

 

[Biff]

Yep remove and wait few minutes or unplug battery and wait even longer.
I'm not sure if it will help, but I know that when you mess with such stuff it's the last step to do.
Good luck!

Thanks, it won't hurt to try.

 

[LX_TREME]

Much easier remove the (-) negative terminal.Bring some empty note to write down everything before you unplug the battery - radio station channel, am, fm etc...

 

[ezgrand]

Newbie needs help on 02 sensor

I bought a pair of NTK sensors for my 91 and it was 79 bucks shipped for the pair. They look like great quality and they come with the factory flange and plug ends. Pretty simple swap. Unplug the old ones and remove them and plug in the new set and install them about a .25 banana job. They are made by NGK who is the leading manufacturer of OEM o2 sensors.
http://www.sparkplugs.com/results_cross.asp?pid=24111&x=24&y=11
Here is a link for them. I believe they also have the sensors for the 1fz.

Hello to Everyone,

On a 92 FJ80 with the 3FE 4.0 engine, are the left and right 02 sensors identical? I got this from an earlier 02 sensor thread.

I get conflicting views from automedicsupply.com which list two part numbers and prices for the left and right 02 sensor.

Has anyone installed the identical 02 sensors from sparkplugs.com
successfully?

thanks!

 

[91Cruizer]

Hello to Everyone,

On a 92 FJ80 with the 3FE 4.0 engine, are the left and right 02 sensors identical? I got this from an earlier 02 sensor thread.

I get conflicting views from automedicsupply.com which list two part numbers and prices for the left and right 02 sensor.

Has anyone installed the identical 02 sensors from sparkplugs.com
successfully?

thanks!

I installed these about a month ago in my 91 3fe. Work great. Replaced OE ones with 176k. No more CEL and smoother idle. I would recomend getting 2 of the OE style NTK sensors. Worked out great for me. The only difference between the L or R sensor is the pig tail length. On the NTK it is more than long enough for both and plugs right in. Just zip tie the excess out of the way. Not factory exact but I never looked back for that price. Shipping took 1 day! Sparkplugs.com gets my vote.