Some turbo/tuning knowledge help

Just got my jeep back from the shop that did an install for me. They also tuned it. But immediately it started having issues. Intermittent issues.

Mainly Limp mode when parked at idle, in drive but full break at idle, and in reverse either stopped or slow rolling. Also got limp mode when shifting from 3rd to 4th at 4500 rpm. If I manually put it in 5th gear and ran the rpm past that point, no issues. and when normally driving, zero issues that I notice.

Attached is a code scan after initial start where limp mode came on.
Also attached is some data logs. I have no idea how to interpret the values on the data logs. But I do see patterns. The LTFT is crazy looking compared to youtube explanations of what it should be. And the STFT is also odd. The short term starts off in the negative and once limp mode comes on, it corrects itself to 0.0~. I also notice the TPS shows a value. I plan to recalibrate that tonight using the key method.

Jeep SRT8 2006 6.1 Hemi
2 CHM 67mm Billet Wheel Turbos, .81AR, T4, 3" V Band Outlet, 3" Compressor Inlet
2 CHM 38mm WasteGates
1 Tial 50mm Blow Off Valve
1 4" OnIII Core Intercooler, 3" In 3" Out
1 CHM Aluminum Custom 3.5" Piping From Intake To Intercooler
1 CHM Aluminum Custom 2.5 to 3 Piping From Turbos To Intercooler
2 CHM Stainless 2.5" Hot Side Piping Black Ceramic Coated
2 CHM Stainless 3" Exhaust Rear Center Exit Black Ceramic Coated
2 Turbo Filters Custom Intake Tubes
1 CHM Custom Stand Alone Oiling System For Rear Mount Twin Turbos
1 All T Bolt Clamps And Silicone Couplers
1 Boost Vacuum Block WIth Rubber Vacuum Lines and Barb Fittings
1 CHM Stage 1 Fuel System 850cc Injectors/Fuel Pump
1 3 Bar Map Sensor
1 CHM DYNO TUNE
1 Upgrade Stand Alone Oil System With Oil Cooler
1 Aluminum Coolant Tank
1 CHM Catch Can 10an Lines Black Fittings
2 5" Rolled Exhaust Tips
1 Powder Coat Cold Side Piping
2 Mobil 1 10w-30 Oil For Turbos

Thanks for any insight. I am talking with my tuner to solve the issues. But I like to have multiple inputs just in case.

https://drive.google.com/open?id=14T...y2u_8STFXs9kmw
https://drive.google.com/open?id=1yp...lHM4j9AHWGhzDf
https://drive.google.com/open?id=1vg...xJrPDX3tevt1h3
https://drive.google.com/open?id=1u2...-GKxPm-D6OjDS9

Cracked plug maybe? I have seen that same behavior before when working on my own car. Cracked a spark plug when loading the headers. Did they change the plugs?

-Geoff

As a matter of fact, last minute, they did. Hmm. Other than pulling every plug, is there an easy way to tell? If not, looks like I know what my plans are tonight.

No help on the time here, but I’m curious how it feels now with the twins?

Quote:

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Originally Posted by mikesfastss

No help on the time here, but I’m curious how it feels now with the twins?

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I haven't got into it really heavy yet. Mainly due to the fear of breaking something with the current issue. But at 25-30% throttle it pushes hard. The slow shift due to stock trans sucks and from a feel perspective, really limits the over all impact. But it is a noticeable difference. We picked up 140hp to the wheels at 7.5lbs of boost. Potentially, that may be with an issue. So we shall see.

Is the fuel system boost referenced or does a second pump come on or anything?
are the o2 sensors plugged into the correct locations?

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Originally Posted by 1BADAIR

Is the fuel system boost referenced or does a second pump come on or anything?
are the o2 sensors plugged into the correct locations?

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all valid questions. And honestly, I have no freaking clue at this point. The shop and the guy building the car does a lot of turbo vehicles. And his work was highly recommended in the mopar crowd down here. Construction and materials looked good. He said he made the tune by doing several driving scenarios shift point wise and then on the dyno. I will be in contact with him tonight and make sure I ask a ton of questions.

I do know that he bypassed a few sensors, like the one that goes into the intake. And programmed in a fixed value set.

Dyno pull info

https://drive.google.com/open?id=18y...4m1QnuD5bv_CYU
https://drive.google.com/open?id=1R7...7iDOC-6w8KvSiT

Quote:

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Originally Posted by furian76

As a matter of fact, last minute, they did. Hmm. Other than pulling every plug, is there an easy way to tell? If not, looks like I know what my plans are tonight.

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It is unlikely they are cracked if they did them after header install. It is hard to tell and you have to pull the spark plug boot. They usually crack on the ceramics, you will see faint gray lines on the white part of the plug. I looked on Google and there are a bunch of pics. A tiny line on it is all it takes.

-Geoff

Oh, and if you log it, you should be able to separate out the misfires by cylinder. That should tell you where to look. If they are all in one, that should be a pretty big clue.

-Geoff

That's good info. I have the shop coming to my house tonight. Pulling the plugs is a nightmare on this vehicle. Most of the coil packs are mounted below other accessories that have to be removed to even get the bolts out. but on the couple of cylinders I checked, they looked clean and new.

The tuner said that the data logs, which I linked above, shows it running rich. So he thinks an injector is stuck slightly open. But the vehicle was running flawless prior to install and tune. And I did a sea foam treatment 2 weeks prior to taking it into the shop for the work.

I will update with what we find tonight. Thanks for all the input and help.

With new tune installed, replaced oil pump as it died, it now has a nice idle and does not limp mode at idle speed so far.

After a few soft runs that spun a limp mode with zero codes or reference info, we think we found the culprit. Shift points. There must be some sort of safety built in some where that when the vehicle shifts, it will over rev slightly. But that over rev is sending the TCM into panic mode. So we backed the RPM range down and that feels like it fixed 70% of the issues. We still have a WOT limp mode issue and a limp mode above 80mph in 4th. But it feels like it could be a programming issue.

Final part is temperature. This thing does not like the cold. Throttle response is super laggy from a standing position to slow roll and it stutters until the temps warm up. Then it runs like a champ. And when full boost is reach at 7psi, I have to remember that just because my foot is off the gas, it doesn't mean the car is ready to slow down!

Update: So after many months of replacing parts (at the shops expense) they reset the tune back to stock. They thought maybe because they tuned it with the transfer case disconnected on a dyno, that maybe there is something there. Turned out, that is true. They have since did a street tune instead of a dyno tune on it. Zero stutter, no codes, no limp mode, and they said it feels noticeably faster than before. They have it for a few more days of driving it to make sure it gets a thorough shake down, but it sounds like the mystery is literally the programming of the TCM. I am just glad they figured it out without anything breaking and without costing my additional money.

I plan to take it to Louisville for an AWD dyno day to get some final numbers and review input. I will post up once it al that gets done.

That's pretty odd, glad they got it sorted out.

Jeeps back, feels solid. No failures so far, thankfully. But now I have some questions from people that may have dealt with similar issues.

Chrysler performance vehicles apparently always have that Chrysler snort/fart/whatever when shifting. Basically that time in between shifts. Now that I have the turbo's rolling, that went from a 1-2 second shift to what feels like an easy 5-8 second shift. the rpms get pushed into the redline area really quick and I believe its related to preventing the trans or motor from over revving or something.

If I use the auto stick, I can do a 1-2 shift at 4500 and it will shift right at 5800 rpm which prevents the snort, 2-3 at 5000 rpm, and 3-4-5 at 5500. And the vehicle will fully pull with no lag between shifts.

Is there a type of tuning that can be done for down shifting or up shifting when at WOT? That will not throw a fit when tuning for the trans and transfer case? Apparently there is 2 areas that need programming or something. Thoughts?


Future plans is 426 rebuild, top to bottom. Paramount or SHR trans (unless I can find a 3rd alternative) Paramount or SHR transfer case ( unless I can find a 3rd alternative).
Once these 3 items are done, I can turn the turbos up a bit. Also plan to get a dyno read from an AWD system in Louisville once the burn everything to the ground movement ends.

make sure your tuner is using hptuners

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Originally Posted by dline

make sure your tuner is using hptuners

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He is, But from what I am reading and hearing in my jeep forums, the 2006 has a different ECM/TCM/PCM or what ever from 2007 and up models. But honestly, I have no clue. He tunes tones of other Dodge vehicles and Jeeps. But mine is a bit of a weird one.

He had to pull almost all of the transmission tuning stuff out to make it work

Are there any good aftermarket controllers available? Spending some money on a good stand-alone might solve a lot of your problems.

-Geoff

Quote:

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Originally Posted by WhiteHawk

Are there any good aftermarket controllers available? Spending some money on a good stand-alone might solve a lot of your problems.

-Geoff

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That's the question of the hour I guess. I have asked on a few of the forums I am on. Several have recommended the tuners the use, but have also stated that if you have such and such PCM or TCM that you can brick your modules. I have seen the write up on how to find out which one you have, but the soft kick board that I should be able to move by hand is hard as a rock and I will have to remove my entire dash section or destroy the kickboard in order to get to where I can see or read the info. But maybe a real mechanic knows a trick lol.

Once I go out to Louisville and also start up some discussions with a few transmission places, Maybe they can give me some input. For now, I will just have to work around it.

I plan to take it to the track tonight if the weather works out. I want to see what my crappy launch times might produce.