2018 Challenger 6.4 with Stroker 426 & Whipple Stalling Issues, Throttle oscillation

[DustinD]

BaseTuneWith180.hpt
07262025Part1.hpl
07262025Part2.hpl

Hello!

I am in dire need of some tune cleanup on my car. This car was built about 2 years ago, since then I've driven it about 4000 miles. The tune has a few problems.

1. The primary problem is that the car shuts off randomly. I think the issue is an oscillation with the throttle. The car is a 6 speed car, when I push the clutch in after say driving in 3rd gear, the car with drop off and go to an idle RPM. I believe the car is having an issue targeting 800 RPMS (the cars natural idle). Instead it drops to 500 RPMs and stalls. **In the 2nd log file, this occurs about 75% into the log**. In the attached video, this occurs at 16:57 I was very lucky to get this to happen while I was logging.

Very commonly when I put the clutch in after driving in a gear, the car will drop to 500ish rpms, then go to 1500 rpms, then back to 500 rpms and this continues for 10ish seconds. I can correct it by pushing the gas to give it a little throttle and it will level off. If I don't do this it will correct itself after about 10 seconds or it will stall.

2. Second issue - The car does not drive itself without the throttle pressed. In other words, the car will stall at low speed if I don't give it gas. The car also gets really jerky if I don't give it throttle at low RPMS. I really have to keep the car 1 gear lower than usual at low speed (very annoying). Is the car drivable? Yes, so I can live with this, but it could be better.

Note: The 2nd log file was not reporting all the parameters, I'm not a HPtuners expert, I dont really know why, but the first log file should give you a picture of what is going on.

Video: https://youtu.be/Etiunl7oGzg

I attempted to give as much information as possible. Any help is very appreciated.

[edcmat-l1]

What fuel injectors are in it?

Do you have the stock unmodified version of the tune file?

[DustinD]

What fuel injectors are in it?

Do you have the stock unmodified version of the tune file?

The only fuel injector information is as follows: FIC 85Lb Injectors

The tune file I uploaded is what was initially loaded to the car after the motor swap and all the work OTHER THAN the fans were changed to turn on at 185 degrees, I believe stock is 205.

I'll try to summarize in as few words as possible, but when I got the car it was running at 230 degrees in cold temps. The car got hot one day and the coolant overflow sprayed a ton of fluid. I did some work and research and found that they left a bubble in the coolant system which was causing the car to run hot. I swapped to a 180 degree thermostat and purged the coolant system. After doing this the car now never goes over 205 degrees on a hot day, and stays around 190 on a normal day (50-80 degrees outdoor temp).

Additionally they didn't secure the hose going from one of the coolers to the top of the motor, this hose rubbed and caused a leak. I replaced this hose and properly secured it. You can see this in this video. https://www.youtube.com/watch?v=E-Co...nel=SecretClub

I don't have a file for a base stock tune, I only have what the shop gave me.

Edit: Also, I believe the issue with the stall is that: Basically when I hit the clutch the car doesn't react fast enough to give it throttle after leaving gear. The car does have a lightweight flywheel, because of this it may be possible it drops RPM too fast for the car to react? I'm not really sure but that would be my hypothesis. A possible solution may be increasing the throttle response of the ECU? Not sure if that's possible.

Thank you for looking into this.

[DustinD]

The only fuel injector information is as follows: FIC 85Lb Injectors

The tune file I uploaded is what was initially loaded to the car after the motor swap and all the work OTHER THAN the fans were changed to turn on at 185 degrees, I believe stock is 205.

I'll try to summarize in as few words as possible, but when I got the car it was running at 230 degrees in cold temps. The car got hot one day and the coolant overflow sprayed a ton of fluid. I did some work and research and found that they left a bubble in the coolant system which was causing the car to run hot. I swapped to a 180 degree thermostat and purged the coolant system. After doing this the car now never goes over 205 degrees on a hot day, and stays around 190 on a normal day (50-80 degrees outdoor temp).

Additionally they didn't secure the hose going from one of the coolers to the top of the motor, this hose rubbed and caused a leak. I replaced this hose and properly secured it. You can see this in this video. https://www.youtube.com/watch?v=E-Co...nel=SecretClub

I don't have a file for a base stock tune, I only have what the shop gave me.

Edit: Also, I believe the issue with the stall is that: Basically when I hit the clutch the car doesn't react fast enough to give it throttle after leaving gear. The car does have a lightweight flywheel, because of this it may be possible it drops RPM too fast for the car to react? I'm not really sure but that would be my hypothesis. A possible solution may be increasing the throttle response of the ECU? Not sure if that's possible.

Thank you for looking into this.

FIC Information.jpg

[edcmat-l1]

The lightweight flywheel may be your problem. They can be very problematic in the GMs and this is the exact scenario. Return to idle. Trying to cure them using the idle adaptive pids usually results in bad overshoot. So instead of it completely stalling you end up with real bad surge.

[DustinD]

The lightweight flywheel may be your problem. They can be very problematic in the GMs and this is the exact scenario. Return to idle. Trying to cure them using the idle adaptive pids usually results in bad overshoot. So instead of it completely stalling you end up with real bad surge.

Any resolution to make the ECU more reactive?

Edit: Maybe raise my idle to 900RPM as a minimum? I'm not 100% sure how to do that.

[DustinD]

Am I crazy or can I modify these values to stabilize the idle?

PID Control.png

[DustinD]

Well I fixed the problem. I modified the PID control for the idle. I got the car hot and drove it around for 20 minutes.
Modified Values.png
07272025.hpl
BaseTuneWith180Modified.hpt

Attached is a picture with the values I changed (they are highlighted in red). I uploaded the new tune file, and a log I did after I loaded it.

The surging is now basically gone, it happens a little bit but it will surge once and instead of a 500rpm differential its a 100rpm differential. Its basically unnoticable unless you're really paying attention. The car doesn't dive into the low rpms anymore. It just goes to its target and holds.

I still have an issue with the car starting after running for a while but I would call that minor as I can just hold the gas and it will start.

Thanks anyways!

[N2speed]

Well I fixed the problem. I modified the PID control for the idle. I got the car hot and drove it around for 20 minutes.
Modified Values.png
07272025.hpl
BaseTuneWith180Modified.hpt

Attached is a picture with the values I changed (they are highlighted in red). I uploaded the new tune file, and a log I did after I loaded it.

The surging is now basically gone, it happens a little bit but it will surge once and instead of a 500rpm differential its a 100rpm differential. Its basically unnoticable unless you're really paying attention. The car doesn't dive into the low rpms anymore. It just goes to its target and holds.

I still have an issue with the car starting after running for a while but I would call that minor as I can just hold the gas and it will start.

Thanks anyways!

Try this for the hot start

[DustinLive]

Try this for the hot start

Thank you sir, I will try this when I get home.