Just read your post.... you may have an egr valve stuck slightly open. With the engine warm check the temp of your egr valve.should only be warm to touch...mine runs around 105 degrees
94 FZJ code 26 running too rich (3 Viewers)
- Thread starter BlackLS1
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- Thread starter
- #22
I considered the egr, I will take a look at that, going to try and replicate the problem. Unfortunately I don't think I'm going to take my landcruiser to King Of The Hammers This year. I'm forced to ride in my friends Jeep ):
Any update?
Bttt
Bttt
Mine is flashing 2 times then 5, then 2 and 6 ... repeat.... Is that CODE 2, 5 and 6? or 25 and 26?
Yes.
With my 94 its fowled O2 sensors. Thought they were worn but after chemical cleaning them they worked.
I still get the code when I do city driving. As long as I do all hwy driving, they stay clean with no codes.
With my 94 its fowled O2 sensors. Thought they were worn but after chemical cleaning them they worked.
I still get the code when I do city driving. As long as I do all hwy driving, they stay clean with no codes.
93yotasr5
Come and take it
Man I'm battling a rich code as well. New plugs, fuel filter, wires, o2 sensors. Inspected the intake tune multiple times. Mine comes on when it's warm at a stop light and then usually goes off after driving for a few minutes. The only thing I haven't touched and it may work for you is cleaning the IAC.
I just had my 80 with 326k start running rough at idle and poor power with code 26 today. I found that a faulty bank 1 oxygen sensor was causing the issue. I would like to note that I had replaced both sensors around 290k when i bought my cruiser with Denso sensors and had a blown head gasket into cylinder #1 around 310k.
I have been slowly trying to chase the cause of slightly inconsistent idle, fuel economy and power for a couple months now (I am a tech so I actually find very little time or motivation to work on my own cars) I have scoped the VAF, o2 sensors, TPS, checked fuel pressure and compression about a month ago and found no issues. So I had figured it was worn fuel injectors.
So today while my idle was very rough and had very low power I started by rechecking the intake boot and replacing the clamps, this made no change. I started wiggling the wiring harness around VAF and other vital sensors and also found no change. I then unplugged the ECT sensor and found no change (which may also be another issue as this should alter idle speed and mixter because the PCM will default to -40 deg F with circuit open) I then unplugged the o2 sensors one at a time staring with bank 2. After unplugging bank 1 my idle quality instantly improved. I also found small amount of moisture inside the connector due to snow we have had recently this is obviously not good but there was very little and it was not located around the sensor pins. I test drove and found engine power had improved and is actually better than it had been in a while.
I do not have my scope or DVM with me at home so I can not see what voltage the o2 sensor is producing. When I had last scoped the sensors I did notice that Bank 1 sensor peak voltage was about 0.15v higher than Bank2. Due to both sensors toggling properly I was not concerned by it. I believe that when my head gasket blow it had contaminated the sensor causing it to bias rich and has been slowly degrading over time. I am currently driving the vehicle with both sensors disconnected. I am going to replace them Monday and relocate them into the exhaust manifolds where the air injection system was previously located. This will allow the sensor heaters to run less theoretically improving their life.
I will try and add updates after I replace the sensors.
I have been slowly trying to chase the cause of slightly inconsistent idle, fuel economy and power for a couple months now (I am a tech so I actually find very little time or motivation to work on my own cars) I have scoped the VAF, o2 sensors, TPS, checked fuel pressure and compression about a month ago and found no issues. So I had figured it was worn fuel injectors.
So today while my idle was very rough and had very low power I started by rechecking the intake boot and replacing the clamps, this made no change. I started wiggling the wiring harness around VAF and other vital sensors and also found no change. I then unplugged the ECT sensor and found no change (which may also be another issue as this should alter idle speed and mixter because the PCM will default to -40 deg F with circuit open) I then unplugged the o2 sensors one at a time staring with bank 2. After unplugging bank 1 my idle quality instantly improved. I also found small amount of moisture inside the connector due to snow we have had recently this is obviously not good but there was very little and it was not located around the sensor pins. I test drove and found engine power had improved and is actually better than it had been in a while.
I do not have my scope or DVM with me at home so I can not see what voltage the o2 sensor is producing. When I had last scoped the sensors I did notice that Bank 1 sensor peak voltage was about 0.15v higher than Bank2. Due to both sensors toggling properly I was not concerned by it. I believe that when my head gasket blow it had contaminated the sensor causing it to bias rich and has been slowly degrading over time. I am currently driving the vehicle with both sensors disconnected. I am going to replace them Monday and relocate them into the exhaust manifolds where the air injection system was previously located. This will allow the sensor heaters to run less theoretically improving their life.
I will try and add updates after I replace the sensors.
I ran my 94 80 with both sensors unplugged for years. I see no difference between new sensors and running with them unplugged other then it idles a little better with new ones.
I have replace the leads in the O2 plug due to water and corrosion. That improved my emissions results 2 years ago but cleaning the O2 (along with cleaning the cats)got me to pass. I used RotellaT and T6 for years. The ZDDP (zink) fouls the O2's and cats making then ineffective, thus why She'll says not to use it in vehicles with cats.
With my 80, I will get code 25 26 with lots of city driving. With lots of hwy driving the CE light goes away till I go back to city driving.
I switch to Chevron Delo 400 HDMO but the CE bulb burned out so I have no idea if the same thing happens with Chevron Delo 400.
My 80 uses a lot of oil so all the zddp gets baked on the cats and O2's
I have replace the leads in the O2 plug due to water and corrosion. That improved my emissions results 2 years ago but cleaning the O2 (along with cleaning the cats)got me to pass. I used RotellaT and T6 for years. The ZDDP (zink) fouls the O2's and cats making then ineffective, thus why She'll says not to use it in vehicles with cats.
With my 80, I will get code 25 26 with lots of city driving. With lots of hwy driving the CE light goes away till I go back to city driving.
I switch to Chevron Delo 400 HDMO but the CE bulb burned out so I have no idea if the same thing happens with Chevron Delo 400.
My 80 uses a lot of oil so all the zddp gets baked on the cats and O2's
My 80 used to use a lot of oil until I had my head rebuilt. Went from using 3qts every 3k on 15w-40 to using 1/2qt every 4K with mobile1 10W-30 and 40 for summer. I plan on replacing the o2 mostly just to turn off the CEL. It runs pretty good with them unplugged though
If I didn't live it in emissions test area I would just run them unplugged all the time.
I have no idea what, if any damage is being done to the motor running then unplugged but with 457,000 mi on motor I have to assume not much as I have drove around 100,000 with them unplugged.
I have no idea what, if any damage is being done to the motor running then unplugged but with 457,000 mi on motor I have to assume not much as I have drove around 100,000 with them unplugged.
I do not live in an emissions area so I don't have to deal with DEQ. I'm just particular and don't like having faults stored. I wouldn't disable the light in case another fault set which is unlikely without me noticing a drive ability issue.
Running with the o2 sensors unplugged is perfectly safe for the engine. It makes the PCM run in open loop so it defaults to a slightly richer condition. I'm not sure with the 1fz but some engines run slightly less aggressive timing as well.
I know in some countries the 1fz was designed with no oxygen sensors and run in open loop all the time. The software is just tweaked to not look at the signals. So I wouldn't be concerned at all running without them and it has obviously worked well for you without causing any issues.
Running with the o2 sensors unplugged is perfectly safe for the engine. It makes the PCM run in open loop so it defaults to a slightly richer condition. I'm not sure with the 1fz but some engines run slightly less aggressive timing as well.
I know in some countries the 1fz was designed with no oxygen sensors and run in open loop all the time. The software is just tweaked to not look at the signals. So I wouldn't be concerned at all running without them and it has obviously worked well for you without causing any issues.
- Thread starter
- #34
havent been on here for a while, i dont have the rich code any more on mine, i believe the last thing i did was change all the plugs with NGK iridium IX and found some corrosion in the connector for one of the o2 sensors and cleaned that out.
- Thread starter
- #35
the obd system will throw a code immediately with the o2 unplugged, also not good for emissions and your cat keeping the o2's unplugged. fuel mileage will also suffer.
I log every gallon of gas and I have no change in MPG with running them unplugged.
I just went thru this AGAIN with my '94. Little background. Threw a 26 10.2015. Pulled fuse to reset to be sure it'd come back. Ordered a new set of O2's because I knew... Code never came back. Fast forward to 10.2016 and threw a code 21 - #1 O2 sensor so I put in the set I purchased the previous year. Code gone...until last month and threw another code 26. This time I just took the truck to SD Trux. John and his crew are great. O2's obviously good. Short story - where the O2 sensor harness plugs into the main wiring harness in the engine bay, there's a wire to the heater core. That connector is right next to the O2 sensor wire and with a little corrosion there was a cross connect and the #1 O2 was getting about 1 volt extra, throwing the code. They replaced the connector, cleaned everything up and she's back to running great. Time will obviously tell.
On my 94 the driver side O2 sensor harness is hard wired into the harness under the intake plenum. I haven't traced the pass side O2 harness. I will have to look for the plug connector.
93yotasr5
Come and take it
Just came out to a leaking heater core this am. I have a feeling its been leaking for a long time. I'm wondering if this was contributing to my code 25/26!
Unless the coolant in getting in the combustion chamber or exhaust, I could see no reason a coolant leak could cause a CEL.
25/26 is a fuel ratio, O2 sensor problem. Rich lean condition.
Could be dirty O2's. My 94 uses a lot of oil, with city driving I get 25/26, code goes away with all hwy driving. The O2's must get coated with oil with city driving and cleaned off with hwy driving.
25/26 is a fuel ratio, O2 sensor problem. Rich lean condition.
Could be dirty O2's. My 94 uses a lot of oil, with city driving I get 25/26, code goes away with all hwy driving. The O2's must get coated with oil with city driving and cleaned off with hwy driving.
