O2 sensor

[supton]

So the 2003 CRV set the money light yesterday, checked it today. Found the following:
-quickly warms up to about 85C but then doesn't seem like it wants to warm up more, 5 minute warmup (to 84C), driving around for 5 minutes or so at 30-40mph. 86C on a short hill, cooled down to 83, was sitting at 87 after backing up the driveway.
-P1457 is set, that's evap, quick look shows a laundry list of things to check before swapping parts. Fun.
-P0134, no activity on upstream sensor (bank 1 sensor 1)

So using Torq I watched both sensors. Unless if I picked the wrong ones they both are moving... they both sit at about 0.6V at idle... and at idle they are smooth. No cycling for keeping the cat warm or for system test. ? I thought they all cycled at idle? Or does the car just not think it's warm enough? Maybe I have a bum thermostat? It's possible that it's original--PO kept all receipts, all work at dealer, and I did not see any mention of replacement.

Watching the plots it sure seemed that both swung quite nicely, as in, I wonder if the cat isn't dead--no apparent dampening, at least not to my eye. But I am not sure I 100% trust what I'm getting out of this ELM327+Torq either.

 

[Davejam]

They should not be smooth lines. A screenshot may help as i'm not totally understanding.
How many miles does the vehicle have? Has the upstream O2 sensor ever been replaced?
Check the wires aren't loose on the upstream. But the replacement part is <$100. That will likely take care of this one.

 

[supton]

2003 CRV with 161,000 miles. Sensors believed to be original.

The O2 signals will wiggle if i goose it, or while driving if i get on and then off. They go all over, I saw 1V on the upstream at one point and both will hit zero. For the most part they are around 0.6V, wiggling around while driving--but at idle they like to do nadda.

I'll see about some screen shots later.

 

[Leo99]

Is this a V6 or I4 engine? When you say they go all over. Do you mean both upstream or the up and down stream sensors?

 

[supton]

It's an I4. Only one pair of sensors.

They go up and down. Both of them. I was expecting a smaller waveform on the downstream.

 

[BrianF]

Also could have a failing thermostat.

 

[supton]

Also could have a failing thermostat.

I'm seeing 87C at Rock and 77-78C elsewhere, when I try to find what the spec is for it. I'm guessing it's working on that basis--I thought it should have been running at 90-95C but maybe it only gets that warm when under load.

 

[BrianF]

Ya I didn't check to see what it should be in that setup. In my GM's they all seem to fall into that 95C mark.

 

[supton]

Ok, took it for a spin.

This was at idle, 53 to 57C, after it had been sitting for a bit..

 

[supton]

And while out driving. No idea what I was doing, on and then off. At least 84C temp.

 

[supton]

And finally, after backing into the driveway, 90C idle.

 

[supton]

The plots seem like gibberish to me. I wish I knew how to properly overlay them (haven't used Torq very much, nor in a while), but even trying to take into account the offset on the x axis, they seem to, at times, just plain not make sense. I'd expect the second sensor to track the first, just more subdued. For a couple hundred dollars I could fire up the parts cannon and replace both sensors (haven't looked what prices are, just noting a cheap cost level) but it'd be nice to diagnose, if possible.

 

[LazyDog]

Here is what you need to do:

1. Replace the ELD/ electrical load detector controls power to all the emission stuff and ABS.

2. If you still have the original thermostat change it

3. With scanner check the engine temperature when cold has to very close to ambient temperature

4. Oxygen sensors are they original, change them.

 

[supton]

ELD, had not heard of that one before. I will hook up a multimeter and watch voltage next then, or see if I can get that off Torq.

 

[LazyDog]

ELD, had not heard of that one before. I will hook up a multimeter and watch voltage next then, or see if I can get that off Torq.

It is on the fuse box in between a 50 and 10amps fuse. The multi meter might not work for checking you need a scope. This thing also controls the alternator output. Very easy to change and cheaper than other items on my list.

 

[Skippy722]

I’d change them both like LazyDog said since your Torque outputs are all over the place.

Once in closed loop mode the upstream should be bouncing up and down while downstream should remain fairly flat. Not sure how Honda does it, but my various Chrysler’s all hit closed loop pretty quickly, within 2 minutes, regardless of coolant temp.

 

[supton]

Looks like an ELD is $36 off Amazon. Guess I start there, although I wouldn't mind scoping the 12V line first. From what I can tell, a bad ELD should trip a code of its own.

 

[javacontour]

As others have mentioned and the code suggests, the upstream sensor seems to be dead.


Frankly, I'd start there and see how things go.

But looking at the downstream, the cat also looks dead. I wouldn't change it right away as it might clean up after replacing the upstream sensor.

I'd look at the upstream O2 sensor as a prophylactic replacement at 160k +

 

[supton]

Looks like Denso is the preferred vendor, not Bosch, not it appears I can get locally anyhow. Will order up some, looks like about $250 to start to debug this one.

 

[javacontour]

Looks like Denso is the preferred vendor, not Bosch, not it appears I can get locally anyhow. Will order up some, looks like about $250 to start to debug this one.

Well, you can test before spending a ton of money...