STFT Main VE dialling etc....

[hquick]

Here's the tune and log from the run home.
This shows the NBO2 voltages.

[joecar]

Interesting...

HO2S1x voltages are shifted down a little (lean), confirmed by wideband AFR (ignore where I put the cursor).

http://img122.imageshack.us/img122/2126/sh02s1xot9.png

[hquick]

Please elaborate Joe????

[joecar]

Oh, I was observing that your HO2S1x voltages swing between 0mV and 750mV... (i.e. the centre voltage would be 375mV rather than 450-500mV) which indicates a lean tendancy, and your WB says about 17 AFR...

they correlate with each other.

Hmmm... the STFT's are trimming to this...!!!

[hquick]

Ahh....OK.
So...any idea how this would happen?

[hquick]

looking at the data it's between 0 and 960???

[5.7ute]

Joe, the average voltage is around 520mv which correlates roughly with his switchpoints in the tune. Is this the wrong way to look at the voltages? I would of thought with the equal times spent over & under the switchpoint an average value would be a fair indication.

[joecar]

Howard,

I had to break off last night, I do apologize...

5.7ute, you're right, the average is ok, I was not looking at it right, please disregard my comment about HO2S1x voltages. :doh2:


But...
look at the wideband AFR, it shows about 17 AFR...
a look in the tune shows B3647 to be EQ 1.00 and B3601 to be 14.63...
the log shows the STFT's are trimming to this, but the wideband says 17.
I expected the wideband AFR to be hugging the commanded AFR...!!!

[hquick]

Damn Joe...what? You've got a life outside of this forum and tuning cars?
Where did you get that? Gotta put that on my list as the next mod I buy. Lol!
I used to have the commanded and actual AFR pretty close...so I don't know what's happened.

[joecar]

My Mrs was yelling at me to eat or sleep or something...:hihi:...I think that's her job...:hihi:

[joecar]

I had thought the HO2S1x voltages were a little low, but I just realized you don't go WOT in that log, so 5.7ute set me straight (I guess I did need food/sleep :D).

[5.7ute]

Howard,

I had to break off last night, I do apologize...

5.7ute, you're right, the average is ok, I was not looking at it right, please disregard my comment about HO2S1x voltages. :doh2:




You had me stressing there for a while Joe. I jumped straight in the deep end & went to an open loop tune so I havent had much to do with narrowband O2 sensors.
IMO the way that both O2 sensors are happy to switch around this point leans toward a wideband problem. Apparently mig welding gas can be used in a pinch to test the wideband sensor.( You should have this at work Howard:grin:). You may have to make something up though as you want to get the gas into the sensor but not around the reference hole in the sensors body. Since the gas removes oxygen you should get a stoich reading.

[joecar]

5.7,
I do apologize... I had been looking thru a whole heap of NBO2 waveforms and my eyes were glazing over...:Eyecrazy:... sorry about that...:redface:... what, you don't normally run OL...? :mrgreen:

I agree with you... the NBO2's are switching happily... the wideband looks like it's off range...

I didn't know mig gas (Ar+CO2) would do that (oh I see, it depletes oxygen from removed sesnor, so O2 should see rich);

or he could feed propane into TB/manifold while engine runs (should go rich), or he could aim a propane torch at the sensor (sensor removed from bung).

He has a mig, oh then that's a good idea.

Cheers,
Joe
:cheers:

[5.7ute]

No worries Joe. I have been single for that long I forget how hard it is to do something with one ear trained for approaching footsteps.:lookaround:
I will try & find the post I read from Klaus at innovate in regards to testing a wideband sensor. If I remember correctly the use of mig gas will only give a stoich reading, the gases needed to read rich are not present in this mix.
Cheers Mick

http://www.innovatemotorsports.com/forums/showthread.php?t=4237&highlight=argon+mig

[joecar]

Mick,

It's funny... she has come to realize that the car is not competing with her...:grin:...she can see it's my hobby/transportation and I get lost in it...:grin:

Klatinn says to use the Ar/CO2 mix, but not pure Ar;

he says a butane from a cigar lighter should make it go all rich, that's an easy test.

:cheers:

[hquick]

When I run through the PLX testing procedure (self testing) it works as described.


1) With the o2 sensor harness UNCONNECTED, at initial power-up does it display 14.6-14.8? If not, what does it display?

2) Reconnect the o2 sensor with the sensor harness. With the o2 sensor UNMOUNTED and exposed to FREE AIR. During the 45 second warmup phase, do the display numbers increase from 14.7 - 20.0 -> LEAN -> Air?

3) When the unit says "air" blow on the o2 sensor. Does it go to "lean"?

4) Does the o2 sensor get warm after 1 minute of power up?

If you answered YES to all of the questions above, the controller is working properly. If not, replacing the sensor should solve the problem.

Yes...I have all of those tools, gases you described...available to me at work. I've switched back to OLSD for the moment and feel 'safer'. I don't know...I don't see what else could be wrong...unless both O2's are shot so doing the same thing.
I will replace them anyway....haven't been changed in 10 years (since new).

[Chalky]

I ran this last Fall and ran it again today. Both times it pulled fuel and leaned the car out until I got a stumble. When I run my WB back against the STFT BEN, My WB says I need to be adding fuel.

I too have a PLX, mine being an SM-AFR. I also have an extra as a backup. Not sure what I trust now. Last Fall I tried it with the MAF not functioning, today with the MAF.