micky > wrote:
>In alt.home.repair, on 21 Aug 2018 10:56:52 -0400,
>(Scott Dorsey) wrote:
>
>
>You seem to know what I wish I knew. Pardon me for horning in on this
>thread.
>
>>The FIRST thing that I would do would be to swap the upstream sensors from
>>side to side and see if the readings move from side to side. If they do,
>
>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.)
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.
>>you have a bad oxygen sensor.
>
>I have a P0171 (Bank 1 too lean) and the same thing for Bank 2 (P017?)
>They tend to point to bad oxygen sensors
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.
>2005 Solara Camry Conv. with 3.3L
>
>>If they don't, you need to start looking on
>>the engine side for vacuum leaks and bad injectors.
>
>I've looked repeatedly and diligently for vacuum leaks. I've sprayed
>starter fluid into every crack. I've checked every hose.
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.
>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.
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.
>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 plots will start to tell you. Also I'd measure pressure at the rail just
to make sure.
>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.
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.
>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.
If you can't see the sensor values, you can't really do real diagnosis.
>>You can put a new converter onto this, but it won't stay good for very long
>>until you sort out the mixture problems.
>
>So I could be ruining my cat converter?
Maybe, if the other bank is running rich. Running lean likely won't hurt
the converter, running rich will.
>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.
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
--
"C'est un Nagra. C'est suisse, et tres, tres precis."