P0171 and P017n Was: What tools do I need? (P0420 Bank 1 catalytic inefficiency on a 15 year old dual-cat vehicle)

In alt.home.repair, on 21 Aug 2018 10:56:52 -0400, snipped-for-privacy@panix.com (Scott Dorsey) wrote:
You seem to know what I wish I knew. Pardon me for horning in on this
thread.

So the sensors are easy enough to remove and insert to just swap them, instead of putting in new? Because they cost so much, about $125 (for Toyotas, a lot more for BMWs I supppose.) (Of course I have the same code on both banks so I guess I won't be swapping, but taking one out worried me.)

I have a P0171 (Bank 1 too lean) and the same thing for Bank 2 (P017?) They tend to point to bad oxygen sensors
2005 Solara Camry Conv. with 3.3L

I've looked repeatedly and diligently for vacuum leaks. I've sprayed starter fluid into every crack. I've checked every hose.
I've cleaned using the special cleaner and then replaced the "filter" in the air cleaner tube. I've checked the air cleaner and it's clean.
I think I once made the codes disappear for 2 or 3 hours** apparently after I sprayed Liquid Wrench on the upper 02 sensor behind the radiator, when I was planning to change the sensor, but I couldn't reproduce that by spraying again. Still, it makes me think there is a leak there, in the threads?, that won't be fixed by merely replacing the sensor.
**Usually the codes reappear 15 minutes after being cleared manually.
I don't know how to check injectors, but since it's both sides and the car runs evenly, maybe they aren't the problem?
The two symptoms are two lights** on the dashboard and the fact that it usually stumbles, hesitates, when starting from a dead start, unless I press the acc just right. **VSC and what I read followed from VSC, trac off.
From reading I did months ago, I'm thinking the upper 02 sensors are more likely the problem than the lower ones, and I should replace the one that is easy to reach.
Or I could diagnose it the way you suggest, but the scan tool I bought didn't work completely and I returned it. I could buy another.

So I could be ruining my cat converter?
I'm hoping it's not that bad because I get 31 mpg on the highway, 1 or 2 mpg higher than what Toyota claims for the highway for a 2005 Solara convertible with 3.3L engine.
It's quite a bit lower in the city and I'm figuring I waste a bunch of gas every time I leave a stop sign and it stumbles.

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I had a similar code 420 on my car. Numerous places told me that meant replacing the cat.
One place said that before doing that... to check out whether there was something in the engine throwing lots fo garbage into the exhaust,in which case replacing the cat would just be a waste of money.
He looked and discovered a defective EGR. He replaced it, and the 420 codes went from happening 15 minutes after each reset to one every couple of days...
Presumably there's still some gunk in the cat which slowly still sets off the alarm, but it's gone from being terminal to having a cold...
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No, the sensors are a bloody pain in the neck to remove and insert. It is no fun at all. But it's a thing you may need to do if you have a problem like the original poster.

Might be, but as I said to the original poster, look at the actual measurements on the scanner as the engine runs and you will see what is actually going on. Your engine may actually be running too lean on one side... if this is the case then you will likely see bank 1 running too rich.

That's never a bad plan. But if you have a leaky or plugged injector it won't find it that way. You -will- find it by looking at the plots from the scanner.

Okay, first of all throw out the Liquid Wrench, get kroil or break-free or something a lot more agressive because you're going to need it. Secondly, ignore the codes and look at the plots and see what exactly is going on with the sensors. The codes get set when a value is out of range for a certain amount of time. The plots let you see what is out of range and when and by how much, and it lets you see if the two banks are tracking or not.

The plots will start to tell you. Also I'd measure pressure at the rail just to make sure.

The sensors -after- the cat only tell you that the cat is good or not, they do nothing else. The sensors -before- the cat are used by the ECU to adjust the fuel mixture. If they produce bad data, the fuel mixture will be wrong in the opposite way as the data.

If you can't see the sensor values, you can't really do real diagnosis.

Maybe, if the other bank is running rich. Running lean likely won't hurt the converter, running rich will.

I'd first worry about fuel pressure. If the pressure at the rail sags badly when you gun the engine in the driveway, fix that. --scott
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I posted this already, and experience tells me both this and the previous one will probably show up, but it's still strange that the first one hasn't showen up on my computer in about 3 hours.
In alt.home.repair, on 21 Aug 2018 10:56:52 -0400, snipped-for-privacy@panix.com (Scott Dorsey) wrote:
You seem to know what I wish I knew. Pardon me for horning in on this thread.

So the sensors are easy enough to remove and insert to just swap them, instead of putting in new? Because they cost so much, about $125 (for Toyotas, a lot more for BMWs I supppose.) (Of course I have the same code on both banks so I guess I won't be swapping, but taking one out worried me.)

I have a P0171 (Bank 1 too lean) and the same thing for Bank 2 (P017?) They tend to point to bad oxygen sensors
2005 Solara Camry Conv. with 3.3L

I've looked repeatedly and diligently for vacuum leaks. I've sprayed starter fluid into every crack. I've checked every hose.
I've cleaned using the special cleaner and then replaced the "filter" in the air cleaner tube. I've checked the air cleaner and it's clean.
I think I once made the codes disappear for 2 or 3 hours** apparently after I sprayed Liquid Wrench on the upper 02 sensor behind the radiator, when I was planning to change the sensor, but I couldn't reproduce that by spraying again. Still, it makes me think there is a leak there, in the threads?, that won't be fixed by merely replacing the sensor.
**Usually the codes reappear 15 minutes after being cleared manually.
I don't know how to check injectors, but since it's both sides and the car runs evenly, maybe they aren't the problem?
The two symptoms are two lights** on the dashboard and the fact that it usually stumbles, hesitates, when starting from a dead start, unless I press the acc just right. **VSC and what I read followed from VSC, trac off.
From reading I did months ago, I'm thinking the upper 02 sensors are more likely the problem than the lower ones, and I should replace the one that is easy to reach.
Or I could diagnose it the way you suggest, but the scan tool I bought didn't work completely and I returned it. I could buy another.

So I could be ruining my cat converter?
I'm hoping it's not that bad because I get 31 mpg on the highway, 1 or 2 mpg higher than what Toyota claims for the highway for a 2005 Solara convertible with 3.3L engine.
It's quite a bit lower in the city and I'm figuring I waste a bunch of gas every time I leave a stop sign and it stumbles.

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In alt.home.repair, on Tue, 21 Aug 2018 14:57:21 -0700, Bob F

Hey, I'll try it. Can't hurt!
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