6.4 Hemi Tuning Help

[AVMPerformance]

I have a rather annoying few issues I'm currently trying to resolve, the car is a 2013 Challenger RT, with a 6.4 Engine, comp cams stage 3 cam, headers, built transmission, Hellcat stock injectors, and 3800 stall torque converter. The car runs.... but not perfect and has some issues I can't seem to resolve. Ill list the issues below. A start up and idle log will be attached, the tune file is attached as well along with the layout for the VCM Scanner to view everything properly. ***For Anyone that wishes to download the tune file, this tune may be catastrophic to your engine if you simply flash it and start, its not recommended to use***

Issue 1: Start up is inconsistent, most of the time start-up it fires right away but you can tell it want more fuel. I have tried adding fuel, but it seems to me it's causing issues elsewhere after it starts. Start-up is not smooth to say the least.
Issue 2: I keep having to make rather large fuel adjustments once the engine is idling and warm. Basically, If the fuel trims are asking for 10% ill add close to that, and it seems fine until after a few days or even a long drive after the
adjustment
it'll want fuel removed. I'm thinking this may be an oxygen sensor feedback issue throwing things off. I made some minor adjustments to the O2 sensor delay tables and increased them. It seemed to help but im un-aware of the proper
way to adjust these tables.

Issue 3: When coming to idle or the car tries to idle, occasionally it seems to either go too lean or rich and the rpms jump and jerks the car, once again seems to be an O2 sensor feedback issue and maybe a combination of not being highly
experienced at tuning and my fueling when coming to idle in one area is lacking, and im missing where that could be.


These are my main issues right now, I have some other items to be corrected as I learn, but these are in the "way" of getting the transmission smoothed out and some other personal adjustments done. My other concern is how the O2 sensors look when the car is running, from my understanding of the sensors, normally with catalytic converters on the car the sensors should basically go rich/lean quickly leaving a smooth-Ish wave pattern. since I'm cat less and this vehicle is for off-road use, does not having cats change the pattern of the O2 sensors? Meaning, the wave pattern that is observed with Cats, theoretically is there to help control the temp of the cats, and obviously keep fueling correct. IF there are no cats can the sensors maintain a consistent temp (theoretically) and the pattern would mostly stay straight? If you observe my log, you will see that it tries to in areas and other areas it goes straight, and the pattern seems erratic and not right.

I'm not looking for someone to jump in and tune the car, I'm looking for feedback on how the log looks, areas that someone sees is an issue, and any information really that help me learn. If anyone can provide feedback I would greatly appreciate it. I know classes will help, but until I can attend them, I want to learn what I can.

[LilSick]

wheres the tune

[Josue Galban]

I have a rather annoying few issues I'm currently trying to resolve, the car is a 2013 Challenger RT, with a 6.4 Engine, comp cams stage 3 cam, headers, built transmission, Hellcat stock injectors, and 3800 stall torque converter. The car runs.... but not perfect and has some issues I can't seem to resolve. Ill list the issues below. A start up and idle log will be attached.

Issue 1: Start up is inconsistent, most of the time start-up it fires right away but you can tell it want more fuel. I have tried adding fuel, but it seems to me it's causing issues elsewhere after it starts. Start-up is not smooth to say the least.

Issue 2: I keep having to make rather large fuel adjustments once the engine is idling and warm. Basically, If the fuel trims are asking for 10% ill add close to that, and it seems fine until after a few days or even a long drive after the
adjustment
it'll want fuel removed. I'm thinking this may be an oxygen sensor feedback issue throwing things off. I made some minor adjustments to the O2 sensor delay tables and increased them. It seemed to help but im un-aware of the proper
way to adjust these tables.

Issue 3: When coming to idle or the car tries to idle, occasionally it seems to either go too lean or rich and the rpms jump and jerks the car, once again seems to be an O2 sensor feedback issue and maybe a combination of not being highly
experienced at tuning and my fueling when coming to idle in one area is lacking, and im missing where that could be.


These are my main issues right now, I have some other items to be corrected as I learn, but these are in the "way" of getting the transmission smoothed out and some other personal adjustments done. My other concern is how the O2 sensors look when the car is running, from my understanding of the sensors, normally with catalytic converters on the car the sensors should basically go rich/lean quickly leaving a smooth-Ish wave pattern. since I'm cat less and this vehicle is for off-road use, does not having cats change the pattern of the O2 sensors? Meaning, the wave pattern that is observed with Cats, theoretically is there to help control the temp of the cats, and obviously keep fueling correct. IF there are no cats can the sensors maintain a consistent temp (theoretically) and the pattern would mostly stay straight? If you observe my log, you will see that it tries to in areas and other areas it goes straight, and the pattern seems erratic and not right.

I'm not looking for someone to jump in and tune the car, I'm looking for feedback on how the log looks, areas that someone sees is an issue, and any information really that help me learn. If anyone can provide feedback I would greatly appreciate it. I know classes will help, but until I can attend them, I want to learn what I can.

Well, mainly you will have to look for what is happening, if it is really the problem due to AFR or something else, I need you to tune it to see it, it seems that fuel may be lacking from what you say, in idle looking for a good AFR 14.7 is enough to be stable, you must focus on fuel, how is your idle spark? I can't see the datalog right now...

[dodgeboy]

STOICH for E10 is 14.1 IIRC

E15 would be richer yet (not really richer but more fuel to air)

@LilSick knows more about Ethanol Thank I do.

[LilSick]

14.2

depends on the stoich of the gas tho

not all gasoline is 14:7

.9 x 14.7 + .1 x 9.6 = 14.19

[AVMPerformance]

I attached the tune file, along with the vcm scanner layout files so the log pulls up properly. The Idle spark sits around 6-8 normally. I actually don't know where idle spark is being "adjusted" since I don't think there is a table that directly control this. I know I changes something recently that caused the idle spark to lower to the 6-8 range, it was previously sitting at 15-25 spark and was erratic when idling. So I'm getting somewhere with this, and a side note, the car runs ALOT better after I had adjusted the O2 sensor Delay tables. I reverted the tables back to stock 6.4 tables and added 15% to both tables, since then driving has been smoother, it acts up less fueling wise, and overall looks better on logs. Still not perfect though...

[AVMPerformance]

wheres the tune

Updated post with tune and vcm files to better view log

[AVMPerformance]

STOICH for E10 is 14.1 IIRC

E15 would be richer yet (not really richer but more fuel to air)

@LilSick knows more about Ethanol Thank I do.

Not running ethanol, or any other fuels. 93 pump gas

[N2speed]

Not running ethanol, or any other fuels. 93 pump gas

then why the hellcat injector? stock ones would have been fine and less of a tuning headache.

[LilSick]

if the cam and heads are worth a damn stock 6.4 injector woulda ended up well above 80 percent dc at wot no?

[AVMPerformance]

then why the hellcat injector? stock ones would have been fine and less of a tuning headache.

Refer to the original message please, I'm trying to resolve issues we are facing and learn. If I wanted easy, I wouldn't be doing this, I would pay someone. I'd appreciate input to my original message; your question doesn't help me.

[vndetta79]

Firstly, I'd say the the injector data in your file doesn't match up with any Hellcat data I have. Not sure where your data is from but I would consider correcting it or you'll be chasing your tail constantly with fuelling issues. Below is data from a stock 15 Hellcat Charger.
Screenshot 2023-08-05 095700.png

Issue 1: Startup issues are usually airflow related rather than fuelling. If the motor is stock, just with a cam and injectors, it shouldn't need too much more "Startup Airflow" to fire up consistently. You shouldn't need additional Throttle/Cranking Startup, or Startup Inj PW if the injector data is right.

Issue 2: more than likely related to the injector data so start there and see how that goes. You're running "Speed Density" so the injector data shouldn't be getting modified.

Issue3: Still fuelling related so start with the injector data and check again. The O2's look good to me. I revised your Scanner layout in the O2's look good. I would look at adding throttle airflow to your scan to compare again the Desired Engine Airflow & Total Airflow.
Screenshot 2023-08-05 101206.png

[PurpleRam]

^^^^^^^^^
What vndetta wrote , start with stock 15 hellkitten values for injector.

I did the same build a few years ago , all of what you’re dealing with is fixable with airflow

[AVMPerformance]

Firstly, I'd say the the injector data in your file doesn't match up with any Hellcat data I have. Not sure where your data is from but I would consider correcting it or you'll be chasing your tail constantly with fuelling issues. Below is data from a stock 15 Hellcat Charger.
Screenshot 2023-08-05 095700.png

Issue 1: Startup issues are usually airflow related rather than fuelling. If the motor is stock, just with a cam and injectors, it shouldn't need too much more "Startup Airflow" to fire up consistently. You shouldn't need additional Throttle/Cranking Startup, or Startup Inj PW if the injector data is right.

Issue 2: more than likely related to the injector data so start there and see how that goes. You're running "Speed Density" so the injector data shouldn't be getting modified.

Issue3: Still fuelling related so start with the injector data and check again. The O2's look good to me. I revised your Scanner layout in the O2's look good. I would look at adding throttle airflow to your scan to compare again the Desired Engine Airflow & Total Airflow.
Screenshot 2023-08-05 101206.png

Thank you, seriously this helps alot. Ill have time here in the next week to do some work on this so hopefully ill update you again. Thank you!

[AVMPerformance]

Wanted to update this post, been awhile since I touched the car, it has been sitting as I'm busy these upcoming months. But I have gotten the injector data loaded, made some initial adjustments to get it to idle and fueling to be within 5% so far. Car runs ALOT better, startup is so much better, and I haven't had the start-up issues as before, it fires every time, exactly as it should. Minor fueling to correct once it fires, but as expected.

My other question would be, is there any airflow adjustments I shouldn't be touching or should be going for first? Same as injectors, I loaded the hellcat data and only modified the VE tables this time, and it runs well. Should I leave the throttle body airflow alone since it's a stock throttle body and adjust the other tables? Or leave them all alone? Guess I'm trying to see if what I was taught is even correct.

[AVMPerformance]

bump...would love feedback on this.

[vndetta79]

Glad to hear things are working out.

With cam tunes, I usually increase the throttle body airflow from 0.00v - 0.30v and then adjust the "Small Range" throttle settings to match. This can help with idle surge. The only other table I've modified, again, only really for helping idle surge, is "Friction-Torque" (ECM12882). Even with displacement increases, this is all I've really played with.

[AVMPerformance]

Glad to hear things are working out.

With cam tunes, I usually increase the throttle body airflow from 0.00v - 0.30v and then adjust the "Small Range" throttle settings to match. This can help with idle surge. The only other table I've modified, again, only really for helping idle surge, is "Friction-Torque" (ECM12882). Even with displacement increases, this is all I've really played with.

Thanks! I seem to be getting a hold of this much better now...

If anyone has input on the cold start that would be great, I got it to start and for the most part, idle smoother. Still not perfect but I went from some serious idle surge at cold start to smoother idle. Its still adding fuel (15-20%) until the engine gets past 110* and then it smooths the fuel trims out.

[f.creek-ranch]

Cold start is evil on this ecm.

Fraction inverse and FA enrichment are active at startup but fades out quickly.
The closed loop enabled table set the cl very soon and after a few seconds Inverse and enrich disappears slightly.

After tuning the engine it’s hard to dial in to be smooth as stock.
Maybe only set cl enabled time higher helps and use fraction and enrichement with wideband to correct it.

[veeefour]

Cold start is evil on this ecm.

Fraction inverse and FA enrichment are active at startup but fades out quickly.
The closed loop enabled table set the cl very soon and after a few seconds Inverse and enrich disappears slightly.

After tuning the engine it’s hard to dial in to be smooth as stock.
Maybe only set cl enabled time higher helps and use fraction and enrichement with wideband to correct it.

I have zero problems tuning them to run like stock even with no cats or with turbo and my LTFTs restet as commaned ��