Cleaning O2 sensor FZJ80 1994 (1 Viewer)

[Desert Dino]

My both sensors were replaced by toyota 2 years ago

After 23 years of backyard mechanics Enola gets here day at Toyota dealership

My fzj80 is privet import not a trough Toyota dealership so it never visited the fancy dealership Enola is used to sweaty red necks drinking beer and even their way with here in the back yard Toyota Japan approved a recall campaign from 1995. Replacement of two O2 sensors free of charge

forum.ih8mud.com

I had a problem in the wire harness sensor no 1 so I drove with the sensor out and not working for a few days I had CEL code 21

I am using OBD1 toyocom so I can read live data

I fixed the wire, but it did not seem to help but after driving at high speed it started working normally once i stoped it stopped working just to work again while driving

I think the heated sensor has a problem to keep the temperature because it is dirty

Is there a way of cleaning it?

I ordered a new NTK one , but it will take time to get

 

[WCBlueSky]

I fixed the wire, but it did not seem to help but after driving at high speed it started working normally once i stoped it stopped working just to work again while driving

Sounds like a loose wire/connection?

 

[Desert Dino]

Sounds like a loose wire/connection?

Not a loose wire it is temperature related

 

[zapatius]

Since we can get parts quickly here, I have always just replaced. I had a friend recommend cleaning them by removing them and letting them sit in a container of gasoline overnight. Never tried it though.

 

[Rifleman]

Is there a way of cleaning it?

When i had customers who didn't want to spend money on new O2 Sensors. We would try to rehab the old ones by first LIGHTLY wire brushing as much of the baked on crap off the end of the sensor that we could. Then we would heat the tip up with a Mapp gas torch to burn off any crap that was left over. I've got to warn you this can be a hit or miss fix. Sometimes it wouldn't work at all, but when it worked, the customer might get a few extra months of use out of his old sensor, and other times a year or longer. It's a roll of the dice, but it's easy enough to do, plus it won't cost you anything other then your time to try it.

 

[bugsnbikes]

a very common problem with these is actually the plugs which hang low and will start to corrode over time causing voltage irregularities.

quick fix is to take some electrical connections cleaner or some rubbing alcohol and get into the plugs pins with a q-tip or even a tiny file.....then smear some dialecteic on the plug and insert /pull plugs a handful of times to clean off the female side a bit.

my codes on 3 different cruisers went away immediately following this.....and it also worked on the high idle issue -IAC plugs pins. went from 2k high idle....to blip to 1200 and settle back down/normal start. id venture to say many intermittent code issues are all due to corrosion at the pins/plugs which will degrade voltage to the ecu and toss codes.

 

[WCBlueSky]

O2 sensors breathe oxygen through the wire connectors, so putting grease or cleaners in the plug is risky.

 

[BILT4ME]

O2 sensors breathe oxygen through the wire connectors, so putting grease or cleaners in the plug is risky.

Huh?

 

[WCBlueSky]

What the Home Mechanic Needs to Know about O2 Sensors

02 (Oxygen) Sensors explained for DIY auto mechanics

www.autotap.com

"Older style oxygen sensors actually have a small hole in the body shell so air can enter the sensor, but newer style O2 sensors "breathe" through their wire connectors and have no vent hole. It's hard to believe, but the tiny amount of space between the insulation and wire provides enough room for air to seep into the sensor (for this reason, grease should never be used on O2 sensor connectors because it can block the flow of air). Venting the sensor through the wires rather than with a hole in the body reduces the risk of dirt or water contamination that could foul the sensor from the inside and cause it to fail. The difference in oxygen levels between the exhaust and outside air within the sensor causes voltage to flow through the ceramic bulb. The greater the difference, the higher the voltage reading."

 

[BILT4ME]

What the Home Mechanic Needs to Know about O2 Sensors

02 (Oxygen) Sensors explained for DIY auto mechanics

www.autotap.com

"Older style oxygen sensors actually have a small hole in the body shell so air can enter the sensor, but newer style O2 sensors "breathe" through their wire connectors and have no vent hole. It's hard to believe, but the tiny amount of space between the insulation and wire provides enough room for air to seep into the sensor (for this reason, grease should never be used on O2 sensor connectors because it can block the flow of air)."

This hole is on the sensor itself on these, not the plug-in connector. The wire plug connector is 6"-18" away from the sensor on these depending on year and they are under the truck and are sensitive to getting wet.

Plugging them in and out a few times cleans/scrapes the terminals and dielectric grease around the outside where the seal is, helps seal out any water when driving through puddles or ponds to reduce corrosion.

On the newer styles (not sure year range) the connector is directly mounted to the sensor and is more susceptible to this issue of "not breathing".

 

[WCBlueSky]

This hole is on the sensor itself on these, not the plug-in connector.

I don't think so, but I could be wrong. The directions on my new NTK sensor specifically said to not use any contact cleaner.

 

[BILT4ME]

I don't think so, but I could be wrong. The directions on my new NTK sensor specifically said to not use any contact cleaner.

See the attached diagram (Note item 2):
Note that the wires from the connector to the sensor are not fully encased and have no path that would be a problem for dielectric grease to clog.

 

[WCBlueSky]

We are talking about a '94 so NTK is the OE not Denso, not sure if that applies. The 3 wires (blue, black, white) are fully insulated the entire length all the way to the plug (otherwise they would short together), not sure what you mean by "not fully encased".

 

[67cruiser]

See the attached diagram (Note item 2):
Note that the wires from the connector to the sensor are not fully encased and have no path that would be a problem for dielectric grease to clog.

View attachment 2520874

So very helpful!

Thank you