Right when I think I got it down....

[Russ K]

My FJO wideband manual has an output calibration chart. At 14.5 AFR there should be 2.45 volts between the 2 wires going to the EIO. At 13.0 AFR, there should be 1.97 volts. Not sure what the voltage is on the PLX, but once you find out, then hook up a volt meter to the 2 wires at your EIO and compare the voltage to the AFR in the scanner. Do this with the engine running.

Russ Kemp

[Dirty Howie]

My FJO wideband manual has an output calibration chart. At 14.5 AFR there should be 2.45 volts between the 2 wires going to the EIO. At 13.0 AFR, there should be 1.97 volts. Not sure what the voltage is on the PLX, but once you find out, then hook up a volt meter to the 2 wires at your EIO and compare the voltage to the AFR in the scanner. Do this with the engine running.

Russ Kemp

You think a guy that doesn't know how to disconnect the AIR pump lines is going to own a volt meter????? Just put this on my to get list

I do remember in the installation guide that there were some voltage referances.....I will check this out and let you know.

[Dirty Howie]

Look at this afr histogram from today. Air was cool and overcast. AFR is 15.1 and goes to 14.7 when some throttle is applied. And my WOT is richer than commanded (12.92).

So maybe my whole AFR range IS off......

I did add one degree of timing but this should make WOT leaner not rciher right???

Still waiting for the call back.


DH

[Dirty Howie]

My FJO wideband manual has an output calibration chart. At 14.5 AFR there should be 2.45 volts between the 2 wires going to the EIO. At 13.0 AFR, there should be 1.97 volts. Not sure what the voltage is on the PLX, but once you find out, then hook up a volt meter to the 2 wires at your EIO and compare the voltage to the AFR in the scanner. Do this with the engine running.

Russ Kemp

Bought a multimeter....I hope it has a voltmeter in it.

Give me a couple of months to figure out how to use it


DH

[domestic rice]

You guys have me confused here. I though that my maf is dialed in, and im back in CL, but if my MAF is almost on the money, why is the stft, ltft, and the wb02 so far off? Here is my log.

TIA

[5_Liter_Eater]

Thats what we're trying to figure out Rice. What is wrong when the narrow bands and wide band do not agree?

I went back to closed loop again this morning. Before the ECT was warm enough to enable CL my AFR error was very close. After CL enabled the LTFTs range from -1 to -8 and my AFR errors range from 3.3 to 9.5. My average AFR as determined by the wide band while in closed loop is 15.67. My overal average LTFT for bank 1 is -6.28. Bank 2 is -7.55.

The fuel trims dont bother me near as much as the closed loop AFR. My narrow and wide band sensors are all plumbed into the header collector so if there were an air leak it would have to be where the headers meet the head. No AIR system on my setup. But my bank 1 and bank 2 trims are very close so that seems less likely. Maybe when they welded my WB bung on they left some pinholes.

[domestic rice]

So whats the general consensus, should we be getting the afr close to 0 or the fuel trims? Does anyone have the two matching up perfectly?

Do you think that since I put headers on, which in turn moved the nb02 back a little, it could have made it read cooler/different than what the ecu is used to seeing?

[Dirty Howie]

Maybe when they welded my WB bung on they left some pinholes.

I actually crawled under the car and tried to check for this. I put some grease around the weld and ran the car......did not see any bubbles.

There is probably a better way to check.......

And PLX never called me back. I got to give them a call. But first I found my ground wire loose to the PLX box and a did a couple of logs and ALL my readings are lean now???!!!! But when the ground wire isn't conected I get a 12.7 afr reading...so that doesn't seem to make sense????????????


DH

[5_Liter_Eater]

This is interesting. Here is my AFR error and LTFT plotted against the airflow table for cross referencing to airflow modes. My switchpoints are all 450mV. Airflow mode is 64 from 36 g/sec in the bin.

I'm not really sure what it means, but it's interesting.

[Dirty Howie]

This is interesting. Here is my AFR error and LTFT plotted against the airflow table for cross referencing to airflow modes. My switchpoints are all 450mV. Airflow mode is 64 from 36 g/sec in the bin.

I'm not really sure what it means, but it's interesting.

Thats to confusing to be interesting for me

I jammed my ground wire into the PLX (I have to have somebody redo the plug wiring) and my afr was hugging the commaded line in WOT and reading 15.1 highway cruise.

If you shoot me the config file I will log mine for comparison.......(for you....too confusing for me )

[EC_Tune]

Bill,
That's the exact problem I and my cohort at work were having with the PLX's. The WB showed "lean" but the NB's showed "rich" in the idle-cruise zones. When my PLX expired and I got my DynoJet Wideband Commander (Ken told me I should have gotten one of those to start with...)
I checked the idle/cruise area again and the dynojet was only off (reads lean) by .1 AFR (accuracy of the sensor) according to my data. And the DynoJet hovered right around 14.7 +&- ~.2 AFR when the o2's were doing their switching.

[5_Liter_Eater]

OK, getting a little despondent now... Maybe I'll hold off on providing any advice for a while...

So my AEM is inaccurate in lower airflow situations and may be accurate at WOT. So I can tune closed loop with fuel trims (yuk) and use the AEM only for WOT tuning and maybe things will be right.

Or I can dump another $529 into a dynojet commander. Anyone have this problem with the LC-1's?

[INTHERED]

Then create a custom histogram in the scanner that plots the LTFT (or SFTF if you're not using LTFTs) against the closed loop mode VS: airflow table.

5_Liter_Eater - I opened my histogram display and looked in the configure histograms table area and the folder that contains assorted histograms and I can't seem to find the Closed Loop Mode vs Airflow Table ? Is there some other place I should be looking ?

Thanks >>>>> INTHERED

[5_Liter_Eater]

It's not a built in histogram. I made it myself. Just create one that plots LTFT's against the closed loop mode VS: airflow table as so:

[Dirty Howie]

Bill,
That's the exact problem I and my cohort at work were having with the PLX's. The WB showed "lean" but the NB's showed "rich" in the idle-cruise zones. When my PLX expired and I got my DynoJet Wideband Commander (Ken told me I should have gotten one of those to start with...)
I checked the idle/cruise area again and the dynojet was only off (reads lean) by .1 AFR (accuracy of the sensor) according to my data. And the DynoJet hovered right around 14.7 +&- ~.2 AFR when the o2's were doing their switching.

I started another thread regarding the PLX.....Doug, please see what they said.:
http://www.hptuners.com/forum/showthread.php?t=12388

Don't all these brands mostly use the same WB sensor?? If so isnt it the WB box that interprets the sensor correctly or incorrectly?? When you went with the DWC (which I almost did till everyone had praise for the PLX ) Did you change to WB sensor or just the box???


DH

[EC_Tune]

Both, as the DWC uses a different connector and sources a different sensor (both LSU 4.2's BTW).

The sensor is "basically" the same (same basic 5 pins but different connectors etc.) but the control mechanisms may be different based on the companies design criteria. WBO2.com has some pretty good info on the LSU 4.2 sensor used in virtually all of the widebands.

[INTHERED]

It's not a built in histogram. I made it myself. Just create one that plots LTFT's against the closed loop mode VS: airflow table as so:

I can't find a closed loop mode VS airflow table. Is this table vehicle and/or software dependant ? Iam running version 2.1.13 on a 2000 C5.

INTHERED

[5_Liter_Eater]

Why are you not on 2.1.18? Anyway, the table itself (in the editor) for my old '99 vette is under engine, fuel control, ol & cl, general and is called 'mode vs: airflow'.

Strangely, when I open an old '99 log file and try to edit the histograms, the Closed Loop Mode VS: Airflow table is not there. If I use a log file from an '05 it is...

[5_Liter_Eater]

Try this to configure the histgram. I've never done a histogram like this before but it "should" work. Use the MAF sensor for the X axis and enter in labels that match the closed loop airflow mode table. The use the LTFTs or AFR error as the plot value.

Lemme know if it works!

[5_Liter_Eater]

Just tried it and it worked for me. Who's your Daddy?