OBDII Warning Won't Clear (1 Viewer)

[elripster]

Is there an option to pull the O2 voltages for all 4 sensors? That's the best way to see what the controller is seeing.

 

[flyingmonkey]

Is there an option to pull the O2 voltages for all 4 sensors? That's the best way to see what the controller is seeing.

Here is the shot of the same log for the other sensor (S1). FYI when I start the truck all sensors immediately start reading except for the one that is getting no reading. I'll try to find my IR reader to see what the cats are doing.

 

[elripster]

That's telling then. Def need to ensure the cat is or isn't working.

 

[flyingmonkey]

So I let it warm up for about ten minutes and the temp readings are:

~450F = Header pipe
~250F = 1st Cat
~140F = 2nd Cat

 

[elripster]

That's actually pretty cool for cats but that second one is way too cool.

 

[flyingmonkey]

Yeah. I was reading cats should be way hotter. Think I should go ahead and pull the trigger on new cats? Or can I take these off and bang them around to see if maybe they’re clogged or something? Everything looks pretty rusted, so it may be a chore to get them off.

Cats ain’t cheap. The set im looking at are magnaflow. Of course there’s that extra California Sunshine Tax (CARB)…..

 

[elripster]

If you can get them off, and blow the soot out, and if they aren't melted, you can probably reuse them. If they melted then they are toast.

 

[flyingmonkey]

If you can get them off, and blow the soot out, and if they aren't melted, you can probably reuse them. If they melted then they are toast.

Roger that, guess I'll try getting them off, blowing them out, and getting them back on this weekend. Things look pretty rusted up so if it goes to s*** I'll just order new cats. While I'm at it I figure I will:

Inspect for holes
Wrap exhaust. Is this worth it since I may have to replace the header pipe and cats?
Clean rust off
Replace bolts
etc...

Any other while I'm in there recommendations?

 

[Bud_Dude]

Getting them off with a sawzall is quick and easy... Just ask the gangbangers... It's getting them welded back in that's the hard part.
Joking aside, on my '95 80 series, I watched the muffler tech (Joel) at Joor Muffler remove mine (which were intertwined around the Slee rock slider mount) in about 5 minutes with a sawzall. Then rattle them around to shake out a piece of welding slag trapped from when he welded them in a few weeks earlier.

 

[flyingmonkey]

Getting them off with a sawzall is quick and easy... Just ask the gangbangers... It's getting them welded back in that's the hard part.
Joking aside, on my '95 80 series, I watched the muffler tech (Joel) at Joor Muffler remove mine (which were intertwined around the Slee rock slider mount) in about 5 minutes with a sawzall. Then rattle them around to shake out a piece of welding slag trapped from when he welded them in a few weeks earlier.

Getting the new one on, if I go that route, shouldn't require welding. It's a direct fit setup. But then gain, we all know how those "should be simple" projects go.

 

[flyingmonkey]

Getting them off with a sawzall is quick and easy... Just ask the gangbangers... It's getting them welded back in that's the hard part.
Joking aside, on my '95 80 series, I watched the muffler tech (Joel) at Joor Muffler remove mine (which were intertwined around the Slee rock slider mount) in about 5 minutes with a sawzall. Then rattle them around to shake out a piece of welding slag trapped from when he welded them in a few weeks earlier.

Did you have your entire exhaust redone? I'm thinking of getting a few quotes just to see how much it would cost. Are you happy with Joor Muffler? Mine sharing how much the work ran you?

I'm going to try and get them out this weekend. If it becomes apparent I should just replace the exhaust, I can't decide if it's something I want to tackle or just hand over to someone else if it comes to it.

 

[elripster]

I have had good exhaust work done at wholesale performance muffler in Escondido. I might have the cats in 80 replaced to see if it helps it run better.

Frank

 

[Bud_Dude]

Did you have your entire exhaust redone? I'm thinking of getting a few quotes just to see how much it would cost. Are you happy with Joor Muffler? Mine sharing how much the work ran you?

I'm going to try and get them out this weekend. If it becomes apparent I should just replace the exhaust, I can't decide if it's something I want to tackle or just hand over to someone else if it comes to it.

I was very pleased with Joor and specifically their welder Joel. I had two problems, at 180K miles the cats were dead and it wouldn't pass smog and I'd developed an exhaust leak a the 'Y' ahead of the first cat and O2 sensor. Pretty sure it was Brian at Brian's Automotive that declared the cats dead, by what means he determined that I don't know...

OK, Had to look it up here, it was May 2016, so longer ago than I thought... I went to a few shops around Escondido; some no name place in an industrial strip mall area that was crazy expensive, Master Brake and Muffler (which was recommended by Brian's Automotive) and Joor. I really liked the guys at Master and have no doubt they'd do a fine job, but they were completely uninterested in attempting a repair to the Y leak and would only quote a new full system from the manifold to the cats for about $1300 parts and labor. Joel on the other hand at Joor was willing to take a shot at getting the existing header pipes off of the manifold (majorly rusted bolts there) and trying to weld up the crack at the Y, then if successful would weld in two new (CA CARB compliant) cats. My recollection is that the initial quote was for about $700 for the work, in any case the total bill from them was $807.

Joel explained that the trick to getting the nuts off the studs at the manifold was to soak soak them overnight in some rust penetrant then bring it to him in the morning and he'd hit it hard and fast with the impact wrench. Not sure whether he cared if the manifold was hot or cold for that... He specifically told me to not try and crank them off by hand with a socket wrench, extensions and breaker bar, and that was almost guaranteed to snap the studs, at which point you have real mess on your hands trying to get them out of the manifold.

So, I went with Joor. Joel was completely successful in getting the pipes off the manifold and repairing the Y in a way that would never fail again, and the new cats went in easily. The only problem he experienced was that the front O2 sensor and bung were destroyed in the Y repair process. I luckily found some weld in O2 sensor bungs on eBay and got them to him (still have one of them laying around here somewhere...). That added about another $100 to the fix for the new O2 sensor and labor. Hope this helps.

A few months after the repair and new cats, and in a true 'senior moment', I inadvertently drove the truck over a large boulder in the Pieology parking lot of all places. Rather than stopping and backing off the rock, I opted to push onward! Bad idea... It was a bigger rock than I estimated and I came down hard landing on the exhaust pipe right behind the rear cat directly on the rock before the rear tire caught it and crawled over it. The result was a 1/2" triangular hole in the exhaust pipe that sounded just great. So it was back to Joel for some more welding, which for about $75 he had fixed up in less than an hour.

 

[flyingmonkey]

So I took it to a muffler shop, told them what's going on and asked them for some advice. The guy there looked at my smog report, measured the temp of the cats, and said it's probably not my cats. He said the temps were fine {460, and 430 respectively so I guess I didn't let it watm up enough before).

He thinks the one (the rear one) giving a voltage reading but not a trim reading should be reading SOMETHING for trim, and not just sitting at zero like the computer or whatever can't see it. So since the system can't pull that specific reading he thinks it may be wiring and my goal should be to at least get some type of reading before throwing money at replacing the exhaust because if it is bad wiring then even replacing the exhaust won't fix it. Makes sense to me, what about you guys.

So the problem is I don't know what or how to test. I've been reading up on testing the 02 sensors but still not sure. If anyone who knows this stuff is willing to help test I have beer, whiskey, wine, champagne, fruit juice, water, and pizza.

 

[Bud_Dude]

I know the O2 sensors pulse or toggle between a lower and higher voltage, but never understood how to really evaluate one as good or bad... These two articles are interesting though...

What the Home Mechanic Needs to Know about O2 Sensors

02 (Oxygen) Sensors explained for DIY auto mechanics

www.autotap.com

Easy Air-Fuel and Oxygen Sensor Diagnosis

Some technicians who have worked in this business for years often still get confused by how to diagnose an air-fuel sensor or are not sure what to look at when diagnosing a rear...

www.autoserviceprofessional.com

I believe the OBDII phone app will let you observe the individual O2 sensor signals to see them pulsing and what their upper and lower voltages are.

 

[flyingmonkey]

I know the O2 sensors pulse or toggle between a lower and higher voltage, but never understood how to really evaluate one as good or bad... These two articles are interesting though...

What the Home Mechanic Needs to Know about O2 Sensors

02 (Oxygen) Sensors explained for DIY auto mechanics

www.autotap.com

Easy Air-Fuel and Oxygen Sensor Diagnosis

Some technicians who have worked in this business for years often still get confused by how to diagnose an air-fuel sensor or are not sure what to look at when diagnosing a rear...

www.autoserviceprofessional.com

I believe the OBDII phone app will let you observe the individual O2 sensor signals to see them pulsing and what their upper and lower voltages are.

Yes it will, and I think I've done what you are talking about. The pics I posted earlier are from about a 30 min drive but there is no reading for the S2 fuel trim.

Unless you are talking about something else?

 

[Bud_Dude]

Yes it will, and I think I've done what you are talking about. The pics I posted earlier are from about a 30 min drive but there is no reading for the S2 fuel trim.

Unless you are talking about something else?

I haven't tried reading mine here... but I'm talking about reading the O2 sensor signal/voltages, not the fuel trim that results from the pre-cat O2 sensor signal. I'll give it a try after I eat some lunch here.. I believe you can also access the O2 sensor voltages for reading at the diagnostics plug on the passenger side firewall below the wiper motor... And then read them with a volt meter. Unfortunately the discussion of that test in the FSM involves the use of the "Toyota hand-held tester" that I gather plugs into the diagnostics plug.

https://forum.ih8mud.com/attachments/d-port2-jpg.2061122/

 

[Bud_Dude]

Ok so I just ran my truck here in the driveway and looked at the O2 sensor voltage plots with the Car Scanner app.. After warming the truck up to coolant temp of around 180 I got the following plots:
At a pretty steady 2000 rpm -

Then after dropping back to idle of about 880 rpm -

Seems like the voltages and pulsing are doing as described in articles with swings on the output side of the cats being smaller… I guess meaning the cats are doing their thing…

PS on my app I got to this screen by swiping to the left from the base screen of RPM and temperature.
I’m no expert on this app and usually just use it to reset error codes on the old van.

 

[Bud_Dude]

PS - Prior to the engine and cats fully heating up the it seemed that the O2S1 and O2S2 signals were both oscillating between around 0.1V and 0.9V... as it got hotter the O2S2 sensor swings got smaller....

Also, interestingly there appear to be no contacts in the Ox1 and Ox2 pins of the diagnostics connector on my '97 80... So my hopes of being able to observe the O2 sensor signals easily and without the OBDII app have been dashed... oh well...

 

[flyingmonkey]

The saga continues. Went to an exhaust place, person there told me I should pass with just one monitor not clearing. Problem is since one smog shop failed me it will be harder to find a shop that will pass me with the monitor still not clearing. That's what they told me anyway. So options are to find a "good" (nudge nudge wink wink) smog shop or replace the rear cat.