Understanding and adjusting 6.1L Hemi fuel trims

[pezfighter99]

Vehicle: 2009 Challenger 6.1L, 6 speed manual with Whipple supercharger /CAI kit. Engine and exhaust is otherwise stock. When taking long highway trips on hot summer days I get the CEL with P0175, 2nd bank too rich. (NO OTHER CEL FAULTS OCCUR.) Fault doesn't occur 'till after 40 or 50 miles. After clearing the fault with a code reader, it doesn't reoccur unless I take another long highway trip on a hot day. In doing some research, I reasoned that the fuel trims can't compensate enough to lean out bank 2. I haven't driven with the HP Scanner connected as, due to my schedule, most of my trips are shorter during cooler evening hours.

For the Whipple supercharger tune, the only mods I've done are in the DRIVER DEMAND section to help driveability. I've checked the FUEL section of the tune but don't find anything remotely referencing fuel trims. I'm a BEGINNER tuner and understand air/fuel or fuel/air ratios but tuning by torque is bizarre. Perhaps I need Harry Potter and a magic wand!

Assistance from an experienced tuner would be GREATLY appreciated. Thanks.

[spoolboy]

Post your tune and a log with fuel trims

[Moparmatty]

You need a wideband in each bank to see what's going on. There's a reason there is two VE tables.

[pezfighter99]

I've attached the tune and log as you requested. I reviewed it and noticed that the long term fuel trims are always quite negative (-20 or lower) with bank 2 generally a few percent more negative than bank 1.

I believe the fuel trims are in closed-loop. What value are the long term trims being compared to???

[tbrtuning]

The fuel trims aren't directly being compared to anything but are a value that represents a correction being made. According to the O2 sensors it is applying that much correction to reach the commanded air to fuel ratio. Long term are learned and short term are current so both added together is the correction being applied at a given time.

It's not uncommon that I see Whipple tunes off enough that the cars even miss and act up on cold starts especially on the older ones. Just did a 5.7 Durango the other day that was off pretty far like this.

[pezfighter99]

Thanks TBRTUNING. I haven't had any obvious miss on cold starts with the Whipple tune although the cold idle is a little rough. Is there some kind of tuning "fix" to ease the LTFT's into running less negative so I don't get the P0175 code for bank 2 on long, hot day (80 deg+) trips???

MOPARMATTY - I've considered adding the wideband's on each bank to monitor the A/F BUT even if they indicate a rich condition, I need to know how to correct it. That's what I'm asking help for. Thanks for the suggestion.

[tbrtuning]

Is this the tune you posted how it was provided by Whipple other than your Driver Demand changes or was it tuned by someone else?

[FstdodgeKY]

TBRtuning will get you in the right direction, but to make adjustments to fueling you have to adjust the injector data pulse width vs airmass. Need to make a histogram logging these parameters which is easily found using the search function. https://forum.hptuners.com/showthrea...el+mass+tuning

[pezfighter99]

TBRtuning - The tune I attached was provided by Whipple. I made the Driver Demand changes after doing some research which actually helped driveability a lot. It's not perfect yet but I'm getting there.

FstdodgeKY - I'll check out the histogram link and see what I can do.

[tbrtuning]

TBRtuning - The tune I attached was provided by Whipple. I made the Driver Demand changes after doing some research which actually helped driveability a lot. It's not perfect yet but I'm getting there.

FstdodgeKY - I'll check out the histogram link and see what I can do.

Do you happen to know if your kit has the Deka 60 injectors like the newer ones?

[Moparmatty]

TBRtuning will get you in the right direction, but to make adjustments to fueling you have to adjust the injector data pulse width vs airmass. Need to make a histogram logging these parameters which is easily found using the search function. https://forum.hptuners.com/showthrea...el+mass+tuning

Since his car is not a NN equipped car he will need to adjust the VE tables to get fueling correct, not the pulse width vs airmass tables.

His data logs show the fuel trims are maxing out at 25%-30%. Comparing his VE tables to my N/A 6.1 VE table values, his are 25%-30% richer in the not in boost areas. Which would explain his issue.

[pezfighter99]

I can't see any numbers on the installed injectors however the original packing list from 06/10/2016 lists "8ea 63# Siemens Fuel Injectors w/o-rings". I looked them up on line and Siemens appears to be affiliated Deka. So I'd say I'm 90% sure they are.

[tbrtuning]

Since his car is not a NN equipped car he will need to adjust the VE tables to get fueling correct, not the pulse width vs airmass tables.

His data logs show the fuel trims are maxing out at 25%-30%. Comparing his VE tables to my N/A 6.1 VE table values, his are 25%-30% richer in the not in boost areas. Which would explain his issue.

The VE isn't that different. If you just do a straight compare it looks like it but they changed the axis so it's misleading

[tbrtuning]

Email me at [email protected] or send me a message at Facebook.com/TBRTuning

[Moparmatty]

The VE isn't that different. If you just do a straight compare it looks like it but they changed the axis so it's misleading

You're right! I wasn't fully paying attention when I looked at it the other day.

The injector data must be messed up or something.

[pezfighter99]

TBRtuning - Were you asking me to e-mail you???

If I added a wide-band, I'd add a DUAL wide-band as MOPARMATTY suggested. What brand, that is considered accurate AND doesn't cost 5 bills, should I be looking at???

Since the NN is disabled and VE is used instead of pulse-width vs air-flow, how "simple" is it to manipulate VE to lean out steady-state cruise somewhat??? I've looked at other posts that attempt to describe VE tuning but I didn't see how to adjust VE for temperature based changed in air density. I realize that higher ambient temperatures decrease air density which would lower VE for a given RPM and load.

In the VE charts in the editor, what exactly in the RATIO that's being compared to RPM??? There are no units and the HPTuner description offers no explanation.

[tbrtuning]

I can dial it in for you remotely if you want. Just send me an email or message. I noticed in your log you never even got into boost but gave a decent bit of throttle. Plenty of improvement to be had over that tune.

Wideband would be ideal but can get it running much better without one. I like the AEM X Series with OBD2 output. 30-0334 part number. It's not a dual wideband but is very easy to log and fast responding.

[Kmoney]

Before you go messing around with the tune for this, I would do a smoke test. I had this very issue for a year after my supercharged 6.1 build and found my intake gasket on bank 1 was blown out by boost. Car ran fine other than popping a bank 2 rich code.

[pezfighter99]

Kmoney -I appreciate your input and agree that it's possible there could be some underlying cause for the Bank 2 rich code. However, the scenario that throws the code is very specific and nothing has changed the way the engine idles or performs under cruse or power and seeing the extreme negative LTFT's leads me to believe the tune is "out of whack".

Tbrtuning - The low amount of throttle you observed is deceiving. After installing the SC kit, the throttle was SO sensitive, the car was almost undriveable and I've driven "hot rods" for almost 50 years. I had to completely relearn how to drive it. I got Whipple to send another tune and it "dumbed" the throttle so much, the car was boring except at WOT. From there I researched, adjusted and tested. Finally, I happened on a 6 speed Hellcat tune and interpolated some of those Driver Demand settings into my tune and now it's close to my ideal. It's still sensitive and I have to be judicious with the throttle to avoid running up someone's ass in lower gears.

I almost had another log to attach for your viewing with 3rd and 4th gear WOT (to 100 and 125) with extra chart parameters. However, in my haste, I saved the layout BUT not the log. Stupid me. I will run and (this time) SAVE another log for your perusal before the tune is adjusted. It might give you additional insight. Thanks.

[Kmoney]

Kmoney -I appreciate your input and agree that it's possible there could be some underlying cause for the Bank 2 rich code. However, the scenario that throws the code is very specific and nothing has changed the way the engine idles or performs under cruse or power and seeing the extreme negative LTFT's leads me to believe the tune is "out of whack".

Tbrtuning - The low amount of throttle you observed is deceiving. After installing the SC kit, the throttle was SO sensitive, the car was almost undriveable and I've driven "hot rods" for almost 50 years. I had to completely relearn how to drive it. I got Whipple to send another tune and it "dumbed" the throttle so much, the car was boring except at WOT. From there I researched, adjusted and tested. Finally, I happened on a 6 speed Hellcat tune and interpolated some of those Driver Demand settings into my tune and now it's close to my ideal. It's still sensitive and I have to be judicious with the throttle to avoid running up someone's ass in lower gears.

I almost had another log to attach for your viewing with 3rd and 4th gear WOT (to 100 and 125) with extra chart parameters. However, in my haste, I saved the layout BUT not the log. Stupid me. I will run and (this time) SAVE another log for your perusal before the tune is adjusted. It might give you additional insight. Thanks.

Reading your post looks just like mines back when I started out. MY car had no symptoms other than a periodic check engine light. Try running off one Ve Table. If it still pops up it is mechanical because nothing in the tune is separating bank 1 from bank 2. Those stock gaskets are known to fail. and the paper ones are even worst with boost.