LS6 944 Misfire

[pormgb]

My car is running a bit rough so I did some logging. I see quite a bit of misfires and I'm not sure what is causing the issue. I'm trying to figure out if there if this tune related. Once in a while, I get a flashing cell when starting from cold but it goes away after a restart. I have attached two logs and the current tune, any ideas would be useful.



LS1B_0133.efiLS1B_0134.efiLS6 944 Derron.ctz

[joecar]

First, check for airleaks in the exhaust (before/after front O2 sensors), and at the intake manifold (after the MAF sensor).

[pormgb]

First, check for airleaks in the exhaust (before/after front O2 sensors), and at the intake manifold (after the MAF sensor).

Checked everything out and I do have what sounds like exhaust leaks after the O2s.

I also took a look at my VE table and looked at some recommendations you gave me some time back.

I compared my VE table to a stock LS6 and my numbers were low in many cells. I took your recommendation of copying the VE table from a stock LS6 then added 8% form 3200 rpm to 5600 rpm. I took the car for a run and done some logging. Misfires have reduced allot.
Take a look at the attached logs.

[joecar]

Checked everything out and I do have what sounds like exhaust leaks after the O2s.

...

These leaks allow air to be pulled in in between the exhaust pulses (i.e. on each low pressure pulses).

[joecar]

...

I compared my VE table to a stock LS6 and my numbers were low in many cells. I took your recommendation of copying the VE table from a stock LS6 then added 8% form 3200 rpm to 5600 rpm. I took the car for a run and done some logging. Misfires have reduced allot.
Take a look at the attached logs.

I'll take a look.

[pormgb]

I'll take a look.

Thanks!!

[joecar]

July 15 Misfire.efi
July 15 Misfire1.efi

Misfire1.efi shows quite a few misfires counts on a few cylinders.
Misfire.efi shows some initially, and then they go to almost none, a big improvement, what changed...?

[pormgb]

Misfire1.efi shows quite a few misfires counts on a few cylinders.
Misfire.efi shows some initially, and then they go to almost none, a big improvement, what changed...?

Nothing changed. I started with misfire (from cold start), stopped for gas then logged misfire1. Misfire was a longer run, I returned from the gas station with misfire. The only real difference would be the car sat in the gas station for about 10min and could have experienced heatsoak.

I do notice that the car runs rougher when warm. On nice cool days, its a ton faster.

[ProperTuningOG]

Any special reason why you are running a, what we assume, stock ls6 MAF only?

[pormgb]

Any special reason why you are running a, what we assume, stock ls6 MAF only?

No, I decided to use the LS6 MAF due to the integrated IAT. Is this a bad thing?

I did some research at the time of the build, and that seemed to be the best way to go.