LS6 944 Misfire

[pormgb]

Ah, good observation by Team208...

is your MAF corrected...?

looking at your log LS1B_133, it seems to me that MAF looks like it is under-reporting (i.e. MAF table needs to go up in some places).

What areas of the MAF table seem low?

[statesman]

Check the condition of your spark plugs and plug wires.

[joecar]

MAF Plumbing.

Attachment 22268

Seems ok, even tho you have no choice.

[pormgb]

I checked the plugs and wires, and everything looks good.

I completed a Calc VET but the results made the car run very rough. I then tried applying only the MAF table and the car idled in the 12s AFR.

Not sure what's going on here. I have attached my Calc VET log, and the values applied to a tune.

I ran the car yesterday with B0120 set to 400 with the pre VET tune (iLS6 944 Derron.ctz), and the car ran quite well. Ran a short log and attached the file (LS1B_Calc VET July 28th.efi)


Calc VET log = (LS1B_0143 orig.efi)

Calc VET applied to original tune (July 20th (MAF+VE Applied) B0120 4000.ctz)

Short Calc VET log collected yesterday with the original tune (LS1B_Calc VET July 28th.efi)


Whats odd is the car ran very well with the tune that I originally posted.

[statesman]

When you do a Calc VET, you need to be in open loop (disable your fuel trims). You also need to be in MAF only mode... your log LS1B_0143 looks like you were in blended mode.

[pormgb]

When you do a Calc VET, you need to be in open loop (disable your fuel trims). You also need to be in MAF only mode... your log LS1B_0143 looks like you were in blended mode.

I wasn't aware of the need to disable fuel trims. I read the Calc VET tutorial and summary notes and did not see that step.

Are fuel trims disabled by setting B4205 to something like 140 degrees disabling closed loop?

[joecar]

( BTW: in your tune, B3618 PE table is set to EQR 0.86 which is incorrect... set it to EQR 1.175 (i.e. 1/0.85) )

[joecar]

If it idles that rich that something is going wrong...

[joecar]

...

I completed a Calc VET but the results made the car run very rough. I then tried applying only the MAF table and the car idled in the 12s AFR.
...
Short Calc VET log collected yesterday with the original tune (LS1B_Calc VET July 28th.efi)

This log show idling at Lambda 0.982 (AFR 14.4).

Whats odd is the car ran very well with the tune that I originally posted.

Let's compare current tune to that one...

[joecar]

I wasn't aware of the need to disable fuel trims. I read the Calc VET tutorial and summary notes and did not see that step.

Are fuel trims disabled by setting B4205 to something like 140 degrees disabling closed loop?

I think statesman is inferring that your front NBO2's are switching slower than usual (about 1.5/s vs 3/s)...