First data run, take a look – third generation f-body message boards basic electricity quizlet

Car is running rough, engine is shaking even at idle and im getting a gas smell which will probably be obvious for you experienced guys when looking at the data, and the DA connecting kept toggling green/red. Other than that this is my first log ever and am hopeful that someone will take a look and let me know what they think, whether it was a proper test log or if I should switch my files up or what not. Its hard to be certain which adx file will work for what is probably a mostly stock tune on the ecm.

This run is with the everything stock hooked up (minus t56 swap items), egr solenoid line to egr has been plugged (i had a engine stumble just off idle), and using existing chip/tune which was set somewhere around 2008 (pre t56 swap) via Wong’s Performance Engineering in Vancouver, WA. I had my autoprom in passthrough mode with the Super_8dm2.ecm imported as the xdf file and 8D_90-91_Corvette.adx loaded (both from tunerpro website).

The first rpm spike was a rolling start then floored, with a quick shift into 2nd and floored for just a moment. 2nd rpm spike i think was simply first gear but held a little longer, then towards the end i did a 2-3k rpm hold for a few moments.

Im assuming the VSS error is due to the Dakota Digital (sgi5?) unit that i put in. The ECM definitely isnt happy with it, but it would only throw an engine light when one of my connections gets loose (needle drops to 0, followed by CEL). But my speedo works normally otherwise, i set it by getting on the highway and adjusting till the odometer tripped 1 mile at the green mile signs consistently.

Engine-wise, everything you listed is new except the wires (i replaced the distributor due to bad pickup coil). I kicked the car over last night in the dark and didn’t see any visible sparks coming from the plugs distributor etc. I think one of my wires might be damaged from touching the headers, thats next on my list to test.

"One clue is that since the ECM is detecting it, all or at least part of the problem has to be on the same side of the engine as the O2 sensor. If it’s a bad plug or wire, it would have to be on that side, since the ECM is "flying blind" on the other side without the O2 sensor."

I looked up BLMs yesterday. If i understand this right, Block Learning Multipliers are used with INT(integrator) to make long and short term fuel adjustments (im guessing via injector pulse widths?) to keep the car running at an ideal air/fuel ratio using rpms plus manifold air pressure (for BLMs) or O2 sensor (for INT). Seems they set 128 as the target value, with a range of 105-150 (not sure on exact range in my ecm). BLMS are divided into cells each containing a range value, and within each of those BLM values is found yet another range of INT values. Am i on the right track? Talking technical is not my strong suit lol.

Still struggling with low BLM’s though. Here’s a screen shot of your BLM history. Note that you didn’t hit a lot of the cells. I’ve also attached the SAUJP ADX file that I’m using to generate this history. Assuming you have no other malfunctions going on, then this is simply tuning related.

Unplug the ECM to reset everything. Then drive around for a while to get the relearn process well established. Then turn on the history view and start trying hit as many cells as you can. You can see the history table being updated in real time.

The one thing that’s off the wall is that your ECM is commanding mid-9’s AFR. That’s mind-bogglingly rich. Without a WB, it’s impossible to say what your actual AFR is, but my guess is it’s probably too rich as well. But if you want a dialed-in tune, you’ll need to get the WB (and preferably hook it up to TunerproRT).

When tuning the VE, try to stay on the rich side of 128. What happens is that if you’re BLM is on the lean side (>128) just prior to going into Power Enrich, the ECM will richen up the PE AFR proportionally to how far above 128 you were. That’ll make your final commanded AFR richer than what you’re programming in for it… i.e., you tell the ECM you want 12.5:1… but ECM sees you were at 134 BLM and decides to make it 12.5 x 134/128 = 12.0:1.