Weird problem with wideband isntall

[wildkard]

I have a 5.3 from a 2003 truck I have installed in my Nova, lt headers and a moderate cam. I have installed a Innovate LC-2 wideband along side the drivers narrowband. I set the wb up to read through the EGR pin on the PCM, using the formula Volts/(volts range / afr range) + afr min = afr. When I log in the scanner I get what seems like a correct afr reading from my custom PID, it follows the narrowband in that header almost exactly, as the narrowband starts to go lean the afr raises and goes to a little over 15, then as the narrowband starts to go rich the afr falls to about 14.4/5 and it goes back and forth like that. The voltage reading from the PCM on the egr PID shows right what it should be reading for the AFR values shown.

The problem I am having is that when trying to use logworks to see if I need to add some offset into my custom AFR PID the logworks AFR reading is incredibly lean, like fluctuating between 19-21, I know beyond a doubt there is no way the engine is anywhere near that lean. I don't know if there is something I have setup wrong in Logworks or what, I left all the parameters at the defaults, 0-5V = 7.35-22.39 afr, and that is what is showing in the log setup window.

I will post some logs tomorrow, I ran off tonight and forgot to grab today's logs off of the laptop, I just figured someone may have had a similar problem before.

[wildkard]

Ok, after the crazy weather here I was finally able to get back to the shop and get the data off of my laptop. Here is the current tune the engine is running as well as a short idle log, during this log the AFR shown in the logworks software never dropped below 17ish, and spent most of the time above 19. At this point all I have done is raise the idle 75 rpm at the higher temps, up the isle spark advance a bit, adjust the spark under and over run values, and ran the idle raf tuning once to get it running well enough to actually drive. It idles decently and goes down the road fairly well as it sits.

I have spent this entire week looking online for someone having a similar problem with no luck. If the weather finally clears up some like it is supposed to tomorrow I am gonna pull a couple of plugs to see what they look like and then run another test at 1200 or so rpm to eliminate any potential problems with the O2s reading with my cam. It isn't a huge cam, it is the GM hot cam, 219/228 .525 and 112 lsa.

wideband install.hpl
ve tuning setup.cfg
idle in park raf.hpt
VCM Scanner.cfg

[mowton]

If the narrowband O2's are holding the AFR to Lambda 1 (AFR readings could be different based on fuels and what you have defined as Stoich) and the HPTuner input through the EGR is set to show the same, then you would just adjust the logiworks offset to equal those 2. The offsets could be different as they are being connected in different ways. One through the PCM's EGR and the other directly to the LC-2 analog output.

Am I understanding the problem correctly?

Ed M

PS according to your log, your trims are +25% lean (adding fuel) yet your STIT is pulling -6 g/sec or so. I think the base airflow in your tune is a bit high for your set up. when O2's are subjected to unburned fuel, they can actually read lean. Check your plugs to see if they are wet. I would run RussK's idle scan to set the RAF. Also, what injectors do you have, the stock ones? Make sure the injector data is correct for the installed injectors.

Ed M

[wildkard]

Motor has stock injectors, and all I have done to the tune is what I mentioned in the second post, the Rusk Idle scan though was done before I had the exhaust on, was surging pretty bad when in drive and rolling and I needed to get rid of that before I could take it to the muffler shop.

What I am trying to do is get the wideband installed so I can finish tuning the motor. If you watch the narrowbands after the motor has warmed up they switch between lean and rich fairly quickly just as I believe they should, and the AFR calc from the wideband seems to mimic that. The problem I am having is that despite what I am seeing in hptuners, the wideband reading in logworks is always lean, very lean, during that entire run it never went below 17, and spent most of the time above 19. Everything I know about engines tells me there is no way the engine is running that rich, I pulled the plugs and if anything they are running a little rich, no gas on them, no gas smell from the exhaust while running, but certainly not what they would look like if they were anywhere that lean.

[mowton]

so you need to setup the logiworks scaling similar to HPTuners. LM programmer sets up the LC-2's analog output to the PCM EGR circuit to be read by the scanner and the user configured scaling performs the scaling to develop the represented FAR/Lambda value. Now Logiworks needs to interpolate this analog value into a representative (matching) reading as well. They are two different reading devices working from one analog signal...am I confused?

Ed M

[wildkard]

The LC-2 has three outputs, a digital serial output for connection to the computer, this output is not configurable in LM programmer, it also has two analog outputs that are configurable, I left the one I am using at its default, 0-5V = 7.35-22.39 AFR, which is what I used to create my custom PID in Hptuners. As far as I have been able to tell the logworks software pulls its configuration data directly from the LC-2, none of the parameters are changeable, they are all grayed out, though they are the same as analog 1.

The weather was finally cooperating today so I was able to work on the car some more, the following log has the MAF and LTFTs turned off as I was getting ready to do some VE tuning using the STFTs, it is an idle run with the latter portion using the scanner controls to set the rpm at 1200. I wanted to eliminate low rpm lean issues caused by the bigger cam. In this log the AFR reading from the wideband in hptuners never goes above about 13.5, but in logworks it never goes below about 17.5.

wideband testing 2.hpl

These next three logs are three runs at doing ve table part throttle tuning using the short term fuel trims instead of the wideband as kind of an experiment. The car runs significantly better with the maf unplugged after I applied the information gathered here. The afr in hp tuners is even lower here, and the afr in logworks hovered around 16.8 to 17.3 or so most of the time.

ve tuning with stft.hpt
loaded ve stft 1st pass.hpl
ve loaded with stft 2nd pass.hpl
loaded ve stft 3rd pass.hpl