Split LTFT - 15% Split

[ChaosActual]

Originally Posted by xc_SS/RS

Go buy a really good torque wrench too if you don't have one that goes low enough in inch pounds

I have a few torque wrenches. I used my 1/4” torque wrench last time and followed the instructions to the T, including the stage 1 torque at 10nm, sequence, and stage 2 +45 degrees for the lower manifold. Hopefully I’ll have better luck with the new gaskets on Monday.

[xc_SS/RS]

I don't think you need to be doing any degree angle after the torque sequence. It should be done like this:

Pass 1: 44 inch pounds (roughly 5nm) and there's a sequence to the bolts to tighten
Pass 2: 89 inch pounds (roughly 10 nm) following the same bolt sequence

No degree angle after either pass

[ChaosActual]

Originally Posted by xc_SS/RS

I don't think you need to be doing any degree angle after the torque sequence. It should be done like this:

Pass 1: 44 inch pounds (roughly 5nm) and there's a sequence to the bolts to tighten
Pass 2: 89 inch pounds (roughly 10 nm) following the same bolt sequence

No degree angle after either pass

Just going off of the instruction manual from SLP..

[xc_SS/RS]

Oh whoops I had no clue you were torquing a supercharger down. Don't mind that post then lol

[ChaosActual]

Alright, I am beyond stumped now. New lower intake manifold gaskets, new supercharger to intake manifold gasket, and new PCV hoses. STILL running 10% lean in bank 2. Unless a part I replaced was faulty I’m really out of ideas. I’m going to try re-flashing the tune tomorrow to start off with fresh fuel trims but other than that I am out of ideas.

[CamaroBarb]

I would check the ALL the valve springs and push rods carefully for problems. Check compression and leak down in all cylinders. Cold and warm. Check the exhaust temps with a infrared at each header runner. See how even they are. Read the plugs too. This should get you some idea where to start looking or not looking internally.

[lazerlemonta]

Try placing a ground wire from head to head and to the body.

[eLeSthree]

Did you change all the settings back to stock, or just the LTM?

I downloaded a 2014 1LE stock tune file from HPTuners repo, and you have several differences in the Fuel/Oxygen sensor tab. I believe I emailed you the file for comparison sake. Why on earth anyone would want to change those settings is beyond me, but I highly suggest putting them all back to stock.

Originally Posted by ChaosActual

Thanks again for that, that solves a lot of my confusion. After changing the value and flashing the new tune it will correct to a positive number but I still have a pretty large spread between banks. I’m about to head to the store to pick up some supplies so I can pressurize the exhaust and check for leaks again.


EDIT: eLeSthree, it appears you were spot on with your initial guess. I pressurized the exhaust pretty well and found a large leak on the front of the bank 2 connection pipe, and a pinhole leak on the exterior of the header flange around cylinder 3, 4, and 6. I’m going to try to inject some permatex copper gasket maker around the pinhole leaks and weld the connection pipes to the exhaust tomorrow. Fingers crossed that this fixes the issue.

[eLeSthree]

Originally Posted by ChaosActual

Alright, I am beyond stumped now. New lower intake manifold gaskets, new supercharger to intake manifold gasket, and new PCV hoses. STILL running 10% lean in bank 2. Unless a part I replaced was faulty I’m really out of ideas. I’m going to try re-flashing the tune tomorrow to start off with fresh fuel trims but other than that I am out of ideas.

Dont have to reflash to reset fuel trims. There is a Fuel Trims Reset button in the VCM Scanner under Vehicle Controls and Special Functions. It looks like a power button at the top.

[ChaosActual]

Originally Posted by lazerlemonta

Try placing a ground wire from head to head and to the body.

I have to run to the auto parts store today anyways so I’ll see if they have any ground straps so I can place a ground wire from head to head. Worth a shot I suppose.

Originally Posted by eLeSthree

Did you change all the settings back to stock, or just the LTM?

I downloaded a 2014 1LE stock tune file from HPTuners repo, and you have several differences in the Fuel/Oxygen sensor tab. I believe I emailed you the file for comparison sake. Why on earth anyone would want to change those settings is beyond me, but I highly suggest putting them all back to stock.

After talking with the tuner and doing a little research on the o2 Min/Max Rich/Lean mV values, they were changed because they were calibrated with a wideband to give a more accurate reading. Seeing as the bank 1/bank 2 values are the same it shouldn’t contribute to a split between banks..

[eLeSthree]

Originally Posted by ChaosActual

I have to run to the auto parts store today anyways so I’ll see if they have any ground straps so I can place a ground wire from head to head. Worth a shot I suppose.




After talking with the tuner and doing a little research on the o2 Min/Max Rich/Lean mV values, they were changed because they were calibrated with a wideband to give a more accurate reading. Seeing as the bank 1/bank 2 values are the same it shouldn’t contribute to a split between banks..

Your GM 02 sensors were calibrated with a wideband? They are narrow band sensors. I dont know everything, but something fishy is going on and I highly doubt the two aren't related. Good luck buddy, hope you get it figured out.

[ChaosActual]

Originally Posted by eLeSthree

Your GM 02 sensors were calibrated with a wideband? They are narrow band sensors. I dont know everything, but something fishy is going on and I highly doubt the two aren't related. Good luck buddy, hope you get it figured out.

Please take this with a grain of salt as I’m not trying to be argumentative and I value your input and the time you have taken to look in to this for me, I’m merely trying to explain my understanding and what I’ve been told by one of the most regarded tuners in my area. The factory tune has 450mV min/max. Meaning a reading under 450mv is lean and over 450mV is rich. 450mV is essentially the trigger point. Having headers followed by a full exhaust(not to mention the plethora of other modifications) is bound to change things. Adding a 100mV threshold before rich/lean is triggered would not cause a split between banks. I reviewed my previous tune(different tuner) before it was supercharged and saw very similar values. Maybe my previous post was too ambiguous as the factory sensors were not calibrated per se, but the tune has calibrated the sensor input required to qualify as rich/lean based upon wideband readings.. If anything, I think that this modification would lessen the split that would be seen by reverting the MIN/MAX to 450mV.

[sixty9fordkiller]

have you done a smoke test yet?

that alone will help you narrow down big time where your problem is....

the smoke test will reveal or rule out a vacuum leak. That alone is a win and a solid step in the right direction

[ChaosActual]

Originally Posted by CamaroBarb

I would check the ALL the valve springs and push rods carefully for problems. Check compression and leak down in all cylinders. Cold and warm. Check the exhaust temps with a infrared at each header runner. See how even they are. Read the plugs too. This should get you some idea where to start looking or not looking internally.

Compression and leak down will probably be the next step. Tried checking the exhaust runner temperature but was having trouble getting accurate readings since the headers are wrapped.

Originally Posted by lazerlemonta

Try placing a ground wire from head to head and to the body.

I gave this a shot since I happened to have a extra ground strap in the garage left over from a previous project. Ran the ground strap between the heads and verified the bolt holding ground to frame was tight. No change..

Originally Posted by sixty9fordkiller

have you done a smoke test yet?

that alone will help you narrow down big time where your problem is....

the smoke test will reveal or rule out a vacuum leak. That alone is a win and a solid step in the right direction

Don’t have access to a smoke machine however I’ve datalogged while doing 3 separate passes with propane, starting fluid, and carb cleaner. No significant changes to fuel trims during this time. I was inclined to believe it was a vacuum leak since the trims even out when holding RPM’s about 1,500-2,000 but after replacing intake manifold gaskets, supercharger gaskets, and throttle body gasket as well as all PCV hoses and clamps I’m stumped. I might buy a smoke machine just so I can be sure though..