Cats usually go early due to fueling problems. So your rich/lean condition is probably your root cause with a potential cat issue as secondary.
Engine shutting off during long trips.
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- #22
If the O2 was failing it directly affects your AFR. Short trips also will result in rich mixture for a higher percentage of the time. And it sounds like there was a fuel delivery problem too, right? If any of that results in knock the truck will react by throwing more fuel at it and retarding the timing.
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- #24
Ok, so I'll look into the o2 sensors. It sounds like that should help with the stalling and the gas mileage.
Also, I get a ticking sound from the cats while I'm driving. I've always noticed this and it is unique to my LC. It sounds like drops of water on a hot surface that disintegrates the water immediately. Any thoughts?
Also, I get a ticking sound from the cats while I'm driving. I've always noticed this and it is unique to my LC. It sounds like drops of water on a hot surface that disintegrates the water immediately. Any thoughts?
I wasn't trying to say you have a bad O2 now, just answering your question of how the AFR could be off "with O2s and ECU". You'd have a CEL if they were bad. The ECU follows a pre-programmed map and uses the front O2 to make minor shifts to the map in real time based upon variances in the specific motor and conditions. The rear O2s primarily exist to 'tattle' on poor cat performance, but also provide secondary tuning input to the ECU.
Some here have noted that replacing O2 prior to CEL have had increased performance. Probably a sign of a lazy sensor that it still within tolerance. The 2UZ appears to be tunes for reliability and longevity vs power and efficiency. Makes sense when you consider it was designed to last 300k and feed on fuel from remote places. Hence, I guess, a wide tolerance band.
I'm also not necessarily saying that you have bad cats. You'd have a rear O2 code if the cats weren't doing their job. Again, just commenting on a common cause of cat failure. In my climate at least, I have not seen lack of driving as a contributor to cat failure. People I've know with dead cats have always been due to an ignored primary failure mode. I do think there is a fueling issue.
A weak fuel system often manifest itself when hot. Vapor lock?
Regarding the noise from the cats... Our exhaust will tick with temp change (warming up cooling down) but should not tick when running unless there is a crack. The water sound you mention is especially puzzling.
Sounds like possible vapor lock.
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- #27
Got it. It seemed odd to me that anything would be out of line without the system throwing a code.
As to the Cats, I definitely have a constant ticking sound. The ticking sound is like a drop of water on hot cast iron and the sizzling sound of the drop as it dissipates. I hope that makes sense...
I checked an I happen to have one month left on the 8 year cat warranty...
if the sound is from a cracked cat, I should be ok.
What kind of gas were you using? 89 or higher octane?
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- #29
I was using 91 octane.
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- #30
I may have found the culprit. Yesterday I got an check engine light and I toook it to my mechanic today. He told me it was a left Bank of the catalytic converter, it's all clogged up. I took it to the dealership and they confirmed the same. Fortunately I still have four months on the warranty for the cats. Couple of last thoughts, I noticed pretty high heat coming from underneath the car at one point, I noticed a ticking sound from the cats, more so in recent times than before, and my gas mileage recently was 11 to 12 miles per gallon.
I will post another update after my cats are replaced.
I will post another update after my cats are replaced.
Darn, I was hoping that the 100-series cats were indestructable, but it sounds like they are not.
I fear that the cats on my 1998 with 188k are clogged, and it is not worth the money for me to replace them with the OEM catalytic converters (~$1400 per side).
Does anybody have experience using flowmasters, or other less expensive catalytic converters on the 100 series?
Has anybody successfully run their 2UZ-FE long-term without catalytic converters?
They no longer do emissions inspections where I live, and my preference is to just get rid of the catalytic converters entirely. (Those evil molecular mothers have the potential to catch your rig on fire; ask me how I know.)
It seems like running the engine without the cats should work fine in theory, as long as you trick the post-cat O2 sensors into delivering a constant low-level signal to the ECU.
Any feedback or insight with regard to the feasibility of eliminating the catalytic converters from the 100-series 2UZ-FE will be appreciated.
I fear that the cats on my 1998 with 188k are clogged, and it is not worth the money for me to replace them with the OEM catalytic converters (~$1400 per side).
Does anybody have experience using flowmasters, or other less expensive catalytic converters on the 100 series?
Has anybody successfully run their 2UZ-FE long-term without catalytic converters?
They no longer do emissions inspections where I live, and my preference is to just get rid of the catalytic converters entirely. (Those evil molecular mothers have the potential to catch your rig on fire; ask me how I know.)
It seems like running the engine without the cats should work fine in theory, as long as you trick the post-cat O2 sensors into delivering a constant low-level signal to the ECU.
Any feedback or insight with regard to the feasibility of eliminating the catalytic converters from the 100-series 2UZ-FE will be appreciated.
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- #32
I did some research into dyno Max, they seem to have good aftermarket cats.
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- #33
Darn, I was hoping that the 100-series cats were indestructable, but it sounds like they are not.
I fear that the cats on my 1998 with 188k are clogged, and it is not worth the money for me to replace them with the OEM catalytic converters (~$1400 per side).
Does anybody have experience using flowmasters, or other less expensive catalytic converters on the 100 series?
Has anybody successfully run their 2UZ-FE long-term without catalytic converters?
They no longer do emissions inspections where I live, and my preference is to just get rid of the catalytic converters entirely. (Those evil molecular mothers have the potential to catch your rig on fire; ask me how I know.)
It seems like running the engine without the cats should work fine in theory, as long as you trick the post-cat O2 sensors into delivering a constant low-level signal to the ECU.
Any feedback or insight with regard to the feasibility of eliminating the catalytic converters from the 100-series 2UZ-FE will be appreciated.
FYI... I've been reading up on your ems cat Replacements. Relatively inexpensive option with all things considered.
What's the update?
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- #35
Nothing really to speak of. I haven't Been on off roading trip yet. I have one coming up next weekend when I'm driving through the desert so I can update afterwards.
Marshotel:
Dont run your truck without cats. Your debt to society and earth is one that demands you abide by what little we do to protect the planet. If you dont wanna run cats on your rig dont drive.
K I am off my soapbox. Please continue.
Dont run your truck without cats. Your debt to society and earth is one that demands you abide by what little we do to protect the planet. If you dont wanna run cats on your rig dont drive.
K I am off my soapbox. Please continue.
Good luck, I would not want to test it in the Mohave desert in the summer!! If it breaks down you can die.
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- #38
I appreciate the concern. I've been out there number of times, and there is no other way to tested the cats then to drive through hot weather to see if it stalls or not. Twice that it happened before was in northern Nevada and enroute to Vegas. I will let you know how goes. I've on the trip many a times and two other trucks with us.
Sounds like a good safe plan keep us posted.
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- #40
Over the weekend I drove up the 14fwy to Mohave desert, through and over the high desert into Sequoia national Park and over to Lake Isabella. It was a total of 250 miles off road and 15 1/2 hours of off road driving, It was especially long as I had to run back and forth for a fellow driver who's car broke down. However, It was not as hot as we had expected. It was in the 80s and 90s versus the over 100's we were expecting.
Regardless, I never noticed any type of stalling or engine shutting off. I am pretty convinced that the old catalytic converter was the issue in the stalling problem. Also this problem seems to be unique to 2006 and 2007 land cruisers as they changed the design of the catalytic converters, from a three Cat design to a two car design In those years.
One last though, If anyone is having problems with this, i think they should consider EMS cat Replacements. They are significantly less than OEM parts and better performance as well.
Regardless, I never noticed any type of stalling or engine shutting off. I am pretty convinced that the old catalytic converter was the issue in the stalling problem. Also this problem seems to be unique to 2006 and 2007 land cruisers as they changed the design of the catalytic converters, from a three Cat design to a two car design In those years.
One last though, If anyone is having problems with this, i think they should consider EMS cat Replacements. They are significantly less than OEM parts and better performance as well.
