LQ4 Tune Question

[YungTyph]

I am struggling to get a decent tune on my swap project- its a cammed LQ4 (sloppy stage 2 copy cat cam) currently MAF disabled trying to set my VE table. My wideband is on the driver side right next to my O2 sensor. I see fairly normal AFR data, but the car feels like its running and reacting rich. The car generally wants to die off throttle and while putting the clutch in.

https://log.tunezilla.com/s/VN8bypi3
This is a recent log I took, I ran the car through gears 1-2-3 and then my fuel cut strangely (almost sounded like anti-lag) and then the car died.

My O2 sensor data seems weird to me, but its possible that this looks normal? figured it would more like 0V and 1V flickers rather than a semi analog looking signal.

Would love any insight on this issue and the tune in general- the car is just not happy yet.

EDIT 9/1/2023: Dying issues and weirdness with idle seemed tied to manual vs auto bin. With an updated manual 6L and updated airflow, the car is happy.

EDIT 9/10/2023: My O2 sensor data WAS weird, they were reporting rich and reacting very slow. This resulted in extremely lean closed loop fuel trims and subsequently my AFR. That "antilag" was basically me leaning out.

EDIT AND CONCLUSION: Cleaned injectors, new spark plugs and routed melted coil pack cables. Tune was OK, was just misfiring pretty badly.

[YungTyph]

https://log.tunezilla.com/s/3lf6iUXA

Additional log from this session. From 136seconds to 200 or so its a 1,2,3 from dead. Died trying to let out the clutch a few times...

Any help is extremely welcome!

[NomakeWan]

Switching only really happens at steady state operation in closed loop. If you're doing pulls the voltage will roughly follow the A/F change instead. The second log shows more switching-type behavior since you're doing cruise.

Don't have specific experience with LQ4s or cam setups however, so I'm afraid that's about as much help as I can offer.

[YungTyph]

Switching only really happens at steady state operation in closed loop. If you're doing pulls the voltage will roughly follow the A/F change instead. The second log shows more switching-type behavior since you're doing cruise.

Don't have specific experience with LQ4s or cam setups however, so I'm afraid that's about as much help as I can offer.

That makes sense, thanks for the reply! I will continue to investigate. All fuel trims are deep into the negatives, so I am assuming I can tune a bit leaner just based on that for regular cruising, and trust the wideband for any WOT stuff. Both of these "pulls" were less than 30% throttle, so still what I would call normal driving conditions.

[MO LS Noobie]

You might look at your tune and see if it was properly segment swapped for a manual transmission. Specifically the throttle cracker and throttle follower settings, there are several settings just for manual transmission under airflow, fuel, and transmission. For larger than stock camshafts typically you need to lower the the VE settings at lower rpm/loads – 10 to 20%, and raise the settings at high rpm/load – about 10% to start with.

[YungTyph]

You might look at your tune and see if it was properly segment swapped for a manual transmission. Specifically the throttle cracker and throttle follower settings, there are several settings just for manual transmission under airflow, fuel, and transmission. For larger than stock camshafts typically you need to lower the the VE settings at lower rpm/loads – 10 to 20%, and raise the settings at high rpm/load – about 10% to start with.

I had a somewhat happy engine with torque parameters disabled with my stock 5.3 before this, thought I could get away with it again. I will go ahead and try a more proper seg swap.

Those VE tables track, seem to be fairly close to my original startup table. Thanks for the reply!

[2xls1]

Here is a stock 04 Silv 60 MT file. I would start with that. There are a lot of things in your file that are just wrong for a 04 60 MT vehicle.

[YungTyph]

Here is a stock 04 Silv 60 MT file. I would start with that. There are a lot of things in your file that are just wrong for a 04 60 MT vehicle.

Youre a legend! Thanks for sending this over, should give me a solid start. The seg swap I just put together was making me a bit nervous haha

[YungTyph]

https://log.tunezilla.com/s/pMgoXXUT Here is the latest idle log I have here. Still working out the table with a fresh XDF/bin combo.

With a new tune all together based off the 04 Silv 6.0L Manual trans from above I have a pretty solid start. The idle is still a bit funny, especially when working up to temp... Wondering what a throttle cracker looks like without a VSS in a manual, just based off air/vacuum? Have reduced my idle timing correction to a pretty flat +/- 5 deg.

Wondering if I should modify the switch voltage on the O2 sensors as it seems to be really top heavy on rich readings, potentially causing some issues?

Going to keep modifying airflow, spark and timing until she seems happier, but would love any input.

[YungTyph]

Update for those following along from home.

Edited the tune a bit- modified idle airflow & spark values, changed idle to 900. Seems happier, but around a minute or two into each start my O2 sensors drop off and I start running really lean. Set O2 sensors to switch at 700 mV now to see if they were reacting late, but that doesn't seem to be the issue.

https://log.tunezilla.com/s/gasngAJB

This log starts around 1min30sec after starting the car. stumbling and odd idle seems more time based than temperature based now. Wondering if I need to start looking into idle decay settings. Screenshot to show the full context, TuneZilla doesnt love longer files it seems...

[2xls1]

What injectors are you using and what is the fuel rail type? Dead head or vacuum referenced with a return? You are only changing the IFR table. There are other tables that need to be changed with different injectors. There are a lot of things I see that aren't quite right too. Guessing this is a swap vehicle. You should list as many details of what the build is for good help with it.

[YungTyph]

What injectors are you using and what is the fuel rail type? Dead head or vacuum referenced with a return? You are only changing the IFR table. There are other tables that need to be changed with different injectors. There are a lot of things I see that aren't quite right too. Guessing this is a swap vehicle. You should list as many details of what the build is for good help with it.

Yikes, thought I had this one pretty good. Its a returnless LS2 style intake manifold and fuel rail. Stock LQ4 bottom end, Elgin E1840P, LS2 Heads, upgraded springs and pushrods. Not running EGR (but zeroed out for my wideband) and not running evap. Heads vent to atmosphere/TB directly, may eventually do a catch can.

I matched the IFR to a known LS2 GTO table, but was unaware there were others... Would love to learn what else needs updated!

[2xls1]

Injectors - Offset vs Volts, Short pulse adder, Short pulse limit, Minimum PW. Some of those tables won't transfer directly from a GTO file because the table labels are different. And just venting crankcase to atmosphere is not a good idea. You should have some kind of PCV system. What about the exhaust system? You're not running open exhaust close to the O2 sensors are you? Sounds like a lot of the problems are starting when it switches to closed loop. I can't make much sense from your logs.

[YungTyph]

Injectors - Offset vs Volts, Short pulse adder, Short pulse limit, Minimum PW. Some of those tables won't transfer directly from a GTO file because the table labels are different. And just venting crankcase to atmosphere is not a good idea. You should have some kind of PCV system. What about the exhaust system? You're not running open exhaust close to the O2 sensors are you? Sounds like a lot of the problems are starting when it switches to closed loop. I can't make much sense from your logs.

Good to know, will investigate a comparable bin if I can find one... After a few seconds of thinking, I believe you are right on the money with the PCV potentially being an issue. Certainly seems to cause excess condensation in my oil system. Exhaust runs for a decent bit after the headers, merges and runs back into a Y pipe then dumps under the car, I think plenty of back pressure.

I am with you, closed loop seems to hit the car like a freight train. I will continue to dig and see if I can implement a simple PVC in the meantime.

[2xls1]

It's not back pressure that is needed. It is you don't want O2 sensors anywhere close to open exhaust so outside air doesn't effect their reading oxygen only in the exhaust. This means absolutely no exhaust leaks anywhere near the O2s. Especially upstream of them and within a couple of feet downstream.