Hemi surging idle. Please help

[mmasedawgg]

Hello all,

I picked up a hemi swapped Rubicon a few weeks ago. It needed lifters and some other things but it was such a screaming deal I just couldn't pass it up. Well, fast forward 3 weeks and about 20 long nights in the garage and I'm beginning to regret buying it.

The vehicle is a 2007 Jeep Rubicon with a 2014 truck motor, and a Getrag 238 6 speed transmission.
It has headers, a "cold air" intake, and I just put the Texas Speed 220/230 cam in it with new mopar non MDS lifters.

I have attempted to make adjustments to the ve tables, spark tables, TB airflow table and a few others to get it to idle properly but I just cant seem to get it right. I have also noticed B1 LTFT is indicating a very rich condition, Tested for vac leaks and no vac leaks.

The idle surges very badly and pops loudly like a backfire at idle (smells very rich) and when in low rpm/high load situations. I am assuming it is just so rich that it is igniting the raw fuel/air mixture and making the popping noise. Also, The red "lightning bolt" light will illuminate and i will lose throttle pedal if i come to a stop and idle too long. I'm at my wits end with this jeep and I'm really hoping one of you can chime in and help me out. I'm not looking for free help and im willing to compensate someone for their time. Its really difficult finding tuners local to me as I live in North Pole Alaska.

Cam Specs intake exhaust
Duration @.050 220 230
Lobe Lift .353 .353
Valve lift @ 1.65 .582 .582
Lobe separation 110
Intake Center Line 108 Drive from work 1.hplJK Hemi, Tune 1117.hptJK Hemi Stock tune.hpt

[N2speed]

according to your log you have an issue with bank 1 02 sensor

[mmasedawgg]

according to your log you have an issue with bank 1 02 sensor

That shouldnt affect my idle this bad though should it? i am contemplating disabling them. Any input on that?

[N2speed]

You can not disable the front 02s that is what helps controls the fueling. so yes it can cause issues as it is dumping fuel on bank 1

[rockystock]

Agree with N2Speed, looks like your front left side O2 sensor is failing. Probably a good idea to replace both, in case an engine issue hurt both...

No cats, right? God bless Alaska. If you do have cats, it would be worthwhile to inspect them, might be damaged...

Tune-wise, looks like:

- you're running a cam phaser lock. May as well disable the other variable camshaft switches ("1 Phaser System" "I Term Reset" "OCV Clean" and "Exh Cam 1 Phaser"). Fortunately, tuning fixed cam is much simpler.

- You may want to re-scale your VE ECT factor table and fan control setpoints for your 180 degree thermostat.


Suggestions attached (USE AT YOUR OWN RISK) - most of the changes are based on a stock 2014 Ram 5.7 tune. The Ram spark tables look a little safer, especially for tuning. Your initial tune was on the right track by raising any timing below 10 degrees up to 10 degrees. 10 is probably a good minimum number with your new cam's LSA.

- When tuning via speed density, you want to have your fuel injector tables set to stock.

- The attached tune also has the stock 2014 Ram VE tables. They are a bit higher than what you were working with, and you'll probably tune them even higher in some places. Let me know if you need help setting up your scanner to tune your speed density.

- I added my current idle settings, also running a mild cam. Hopefully they will give you a better starting point. As long as your idle isn't causing you to stall, you'll want to get your fueling dialed in (looking for zero fuel trims throughout your VE range) before focusing on the idle. I've found it's good to try to soften the spark proportional and make the throttle body handle most of the control. Start logging your idle desired RPM and make a math for Idle RPM Error: Engine RPM - Idle Desired RPM. Plot the error on your charts and you can more easily see what's going on with your idle. Here's a great thread on the idle controls:

https://forum.hptuners.com/showthrea...&highlight=ngc

You will want to invest in a wide band O2 sensor for your WOT tuning.

2022-11-19 JK Hemi Tune 001.hpt
2014 Ram 5.7 Hemi Stock 68153764AH 1429901266.hpt

[mmasedawgg]

Thanks so much Rockystock, here?s a little bit more information on what I?ve done to try and figure out the o2 sensor issue. Yes I do have Cats on my jeep. I?m not sure the condition of them though.

I have already replaced the b1 sensor and it did not fix the issue and that?s why I started testing everything.
P0031 - HO2S Heater Control Circuit Low (Bank 1, Sensor 1) (SES, Current)
P0138 - 02 Circuit High Voltage (Bank 1, Sensor 2) (Pending)
P0158 - 02 Circuit High Voltage (Bank 2, Sensor 2) (Pending)

I have recently unplugged the pcm and o2 sensor harnesses and checked resistance of all wires related to the oxygen sensor system and everything checked out flawlessly with 0.0 ohms on every single wire. The grounds all check out to engine ground with 0 ohms when the key is off and 2.5 ohm when the key is on. I have tested the o2 sensors with a multimeter and they all check out as well. (8 ohms across the heater element)
After that I did key on voltage for the heater circuits and sensor wires.
B1S1 tested as follows
Red: 2.5V
Orange: 4.25V
Brown: 2.7mV
Black: 2.5ohm to engine ground with key on

B1S2
Green: 2.5V
Grey: 4.25V
Violet: 2.5mV
Black: 2.5 ohm to engine ground with key on

B2S1
Red: 2.5V
Yellow: 4.25V
Tan: 2.9 mV
Black: 2.5 Ohm to engine ground w key on

B2S2
Green: 2.5V
Pink: 4.25V
Grey: 2.5mV
Black: 2.5 ohm to engine ground w key on

[rockystock]

Checking the cats - as a first step you could lightly rap them with either your fist or rubber mallet (lightly...). Any rattles = time to delete the cats, and try to blow out the rest of the exhaust (little pieces of ceramic might block exhaust downstream). I reverse-flowed my mufflers and mid-pipe / x-pipe using a shop vac using the vacuum discharge to blow, and tapped the pipes with a rubber mallet while blowing. Leaf blower might work well too.

Looks like your O2s are fine. Your log showed both banks tracking exactly the same, until airflow started going up. I'll bet the cats were ruined before you bought it - that starting tune was pretty messy. If your cats are done, I'd recommend deleting them first and get the tune fully dialed in. THEN replace the cats if you want.