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2018 PCP Scat Pack w/dynamics
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Discussion Starter · #1 · (Edited)
Hey guys, I'm in a bit of a pickle.

Backstory: Over the summer, I installed kooks LT headers w/catless midpipes and had it tuned. After receiving it, I felt it just wasn't running right (weird warm starts, rough idle). I spoke with the tuner, and he said it was more than likely a mechanical issue. After a few weeks the engine light came on. I let it go for a little bit, but finally took it to a dealer to have it checked out. I was told every time they tried to hookup to the pcm, it would just crash their system and they would have to start over. They basically told me there is nothing they can do, and to visit a professional tuner for further assistance. I visited a different tuner, they ran the obd scanner, and said it was related to the o2 sensors. Today, I was going through the carwash, and the engine light started flashing (I read this is serious and could be a cylinder misfire). I turned off the car and back on, and I was just shown a solid check engine light again.

I guess I'm just not sure what to do from here. I don't know if its the tune itself or something actually mechanical. I don't want to dish out $600 on a tune and have the same issue, but I guess I'm running out of options. Any advice guys? Should I get it retuned? Take it to another dealer? Replace the o2 sensors? Any input would be greatly appreciated, thanks.
 

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The Bacon Hauler (‘12 Cop Charger)
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Hey guys, I'm in a bit of a pickle.

Backstory: Over the summer, I installed kooks LT headers w/catless midpipes and had it tuned. After receiving it, I felt it just wasn't running right (weird warm starts, rough idle). I spoke with the tuner, and he said it was more than likely a mechanical issue.
This seems like an oddly dismissive response by the tuner. I would have expected him to at least see what’s in the datalogs, but I guess if you do not have a handheld tuner to generate any, it would be hard to provide them to him...

After a few weeks the engine light came on. I let it go for a little bit, but finally took it to a dealer to have it checked out. I was told every time they tried to hookup to the pcm, it would just crash their system and they would have to start over. They basically told me there is nothing they can do, and to visit a professional tuner for further assistance.
This sounds like a cop-out. Did you tell them beforehand that you had a non-stock tune? My guess is they didnt want to get involved and cooked up that story about the crashing scanner.

I visited a different tuner, they ran the obd scanner, and said it was related to the o2 sensors. Today, I was going through the carwash, and the engine light started flashing (I read this is serious and could be a cylinder misfire). I turned off the car and back on, and I was just shown a solid check engine light again.
Did they provide anymore details than that? The O2 sensors are only listened to after it’s warmed up, are the rear ones turned off?

I guess I'm just not sure what to do from here. I don't know if its the tune itself or something actually mechanical. I don't want to dish out $600 on a tune and have the same issue, but I guess I'm running out of options. Any advice guys? Should I get it retuned? Take it to another dealer? Replace the o2 sensors? Any input would be greatly appreciated, thanks.
You need to start from scratch IMO. The exhaust mods shouldn’t require a modified tune to run. Get the stock tune reloaded and go from there. If the CEL returns, have the codes pulled and start working them. If not, leave the tune stock, it won’t hurt anything.
 

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Discussion Starter · #3 ·
This sounds like a cop-out. Did you tell them beforehand that you had a non-stock tune? My guess is they didnt want to get involved and cooked up that story about the crashing scanner.
I didn't mention the tune, but they found out pretty quickly.

Did they provide anymore details than that? The O2 sensors are only listened to after it’s warmed up, are the rear ones turned off?
I need to double check the obd reading, I can't remember the specifics. The tuner didn't tell me what sensors he turned off, but everything seemed to be good the first week or so (no CEL). I can ask him tomorrow to confirm.

You need to start from scratch IMO. The exhaust mods shouldn’t require a modified tune to run. Get the stock tune reloaded and go from there. If the CEL returns, have the codes pulled and start working them. If not, leave the tune stock, it won’t hurt anything.
Yeah this might be the way to go. Narrow down the issues. Thanks for the input!
 

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...finally took it to a dealer to have it checked out. I was told every time they tried to hookup to the pcm, it would just crash their system and they would have to start over. They basically told me there is nothing they can do, and to visit a professional tuner for further assistance.
There's nothing you can do to your car that would prevent a dealer's from communicating with it, especially to just retrieve fault codes. My best guess is because of your mods they just didn't want to help you out which IMO is shitty. Or you got hooked up w/some lazy and/or ignorant advisor, which unfortunately can happen.

You've got misfire (flashing CEL) so do the obvious - check all plug & coil wires/connections, and the condition of the plugs themselves - make sure you didn't crossthread/crack the insulators/etc during the header install. If you don't find anything out of the ordinary I would suggest another dealership. So long as you didn't directly damage anything during the install they can push any other repair through under warranty. Headers/tunes aren't that big of a deal.

PS - as others mentioned, put the factory engine cal back in it as well to see if this is a tune-induced misfire (unlikely) or if you're chasing something else.
 

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Since you've eliminated the cats putting the stock tune back will illuminate the CEL right away IDK if it will go into limp mode or not but if it reads zero cat performance it might.
 

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Since you've eliminated the cats putting the stock tune back will illuminate the CEL right away IDK if it will go into limp mode or not but if it reads zero cat performance it might.
^Yes there will be P0420/0430 faults (and possibly O2 slow response/performance faults) but the point is to see how the misfire condition changes, if at all. That said cat efficiency and/or O2 faults will not put the veh into limp in.
 

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Discussion Starter · #7 ·
There's nothing you can do to your car that would prevent a dealer's from communicating with it, especially to just retrieve fault codes. My best guess is because of your mods they just didn't want to help you out which IMO is shitty. Or you got hooked up w/some lazy and/or ignorant advisor, which unfortunately can happen.

You've got misfire (flashing CEL) so do the obvious - check all plug & coil wires/connections, and the condition of the plugs themselves - make sure you didn't crossthread/crack the insulators/etc during the header install. If you don't find anything out of the ordinary I would suggest another dealership. So long as you didn't directly damage anything during the install they can push any other repair through under warranty. Headers/tunes aren't that big of a deal.

PS - as others mentioned, put the factory engine cal back in it as well to see if this is a tune-induced misfire (unlikely) or if you're chasing something else.
Unfortunately, I don't have the factory pcm. I wish I had kept the original. Is it possible to do a factory reset on the unlocked one? I might just run it by another dealership, because I think you might be right (about the first dealer not wanting to work on modded cars).
 

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2020 Dodge Challenger Hellraisin Scat Pack
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While the tuner's attitude appears dismissive he probably is on to something.

Last thing touched first thing suspect is the saying.

Except in this case 2nd thing touched, the exhaust system, is suspect. You need to be sure the exhaust system is leak free. There is some indication a smoke test is recommended to ensure a completely leak free exhaust.

You also need to be sure the O2 sensors are securely connected to the wiring harness and harness and sensor leads are properly routed and secure.

Hopefully you didn't touch, clean the O2 sensor tips or use anti-seize during assembly.

Once you are sure mechanically there is no reason for the behavior assuming it remains then you can go back to the tuner and be on firmer ground. 'course one hopes you have chosen a tuner and your car is not his first or 2nd car he's ever worked on.
 

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Ok, first rule of Rocket Travel is "when in doubt, return to baseline"

I agree that your Tuner is not giving you straight scoop and that headers alone will not cause fault codes. My guess is that your tuner "over compensated" for an engine that does not need over compensating.

So..... ditch the "tune" and return to the stock programming. What happened to your factory PCM?
 

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Unfortunately, I don't have the factory pcm. I wish I had kept the original. Is it possible to do a factory reset on the unlocked one? I might just run it by another dealership, because I think you might be right (about the first dealer not wanting to work on modded cars).
Can't say I have experience working on 'unlocked' controllers but so long as the EEPROM is writeable (which I'm confident it is) then you should be good to go - the dealer's service tool uses your VIN to look up the 'factory' engine calibration at which point they should be able to reflash to latest/greatest PCM software.

EDIT - there may be some caveats here since I don't know exactly what has been done to you PCM, ie, VIN mismatch/other memory alterations (there is a chance that whatever was done to your PCM really does cause issues when a dealer tries to use wiTech/their diag tool). Worst-case you may need to buy a replacement PCM and have that programmed. But if the ultimate outcome is that you have driveable car I'd say it's money well spent, IMO.

PS - what part of the country are you in?
 

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Can you read the codes in the EVIC (center of the dash)?

On many of these cars you can scroll through the menu to diagnostic and it will read the codes one by one by pressing OK after each code is displayed.

Let us know if you can do that and what the codes are.

Without knowing the codes - we're guessing. My best guess would be one of the oxygen sensors or it's wires are damaged.

Do you have a wideband Air/Fuel gauge installed?
 

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Discussion Starter · #13 ·
Ok, first rule of Rocket Travel is "when in doubt, return to baseline"

I agree that your Tuner is not giving you straight scoop and that headers alone will not cause fault codes. My guess is that your tuner "over compensated" for an engine that does not need over compensating.

So..... ditch the "tune" and return to the stock programming. What happened to your factory PCM?
So the tuner sent off my PCM to a 3rd party to have it unlocked. I believe it is the same unit.

Can't say I have experience working on 'unlocked' controllers but so long as the EEPROM is writeable (which I'm confident it is) then you should be good to go - the dealer's service tool uses your VIN to look up the 'factory' engine calibration at which point they should be able to reflash to latest/greatest PCM software.

EDIT - there may be some caveats here since I don't know exactly what has been done to you PCM, ie, VIN mismatch/other memory alterations (there is a chance that whatever was done to your PCM really does cause issues when a dealer tries to use wiTech/their diag tool). Worst-case you may need to buy a replacement PCM and have that programmed. But if the ultimate outcome is that you have driveable car I'd say it's money well spent, IMO.

PS - what part of the country are you in?
I'm currently located in central texas.
Can you read the codes in the EVIC (center of the dash)?

On many of these cars you can scroll through the menu to diagnostic and it will read the codes one by one by pressing OK after each code is displayed.

Let us know if you can do that and what the codes are.

Without knowing the codes - we're guessing. My best guess would be one of the oxygen sensors or it's wires are damaged.

Do you have a wideband Air/Fuel gauge installed?
I wasn't aware of this feature. I'll go check in a bit and report back.
 

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Discussion Starter · #14 ·
Also guys, not to change the subject, but how would you guys go about finding the right tuner? I have several local shops around here, which seem to have good feedback. But I'm also a few hours away from houston, which has some of the best tuners across texas.
 

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Also guys, not to change the subject, but how would you guys go about finding the right tuner? I have several local shops around here, which seem to have good feedback. But I'm also a few hours away from houston, which has some of the best tuners across texas.
Simple. If you're in Central Texas go to Tapped Performance. Done. He will get you fixed up. I cannot recommend most others, maybe Flyin Ryan near Houston.
 
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