[angryBits]

Let me give you some back story...

I've bought 3 Supercharged GM products in the last 4 years.
2015 ZL1
2017 Z06
2018 ZL1 1LE

All Manual transmission
All NPP exhaust
All supercharged
All run like $#!T essentially from day one.

The 2015 ZL1 was tuned and then problem free after.
The Z06 always ran like poop, I never figured it out.
My ZL1 1LE is now behaving exactly like the Z06 -- like its constantly in and out of limp mode.

For all three I had wired in the same switch to disable the NPP fuse. Basically when the switch is off, its like the fuse is out. When the switch is on, the fuse is in. I do this because I want to be able to quiet down the car while in the neighborhood and then make it LOUD AS F elsewhere.

As a desperate last attempt to figure out why I'm having these problems I put the NPP switch back to normal (fuse in) and pulled the negative battery cable. I have no other mods to put back...

After putting the cable back, the car was perfect! I drove it around for 2 weeks problem free. So today I flipped my NPP switch and boom, limp mode. Not the next day, not hours later -- it happened within minutes!

Whats weird is, both my Z06 and my ZL1 1LE both gave me the same O2 sensor error code about the time this started (I forget the #). No Check Engine Light. But there's a code.

I'm literally pulling the negative battery cable again right now and going to try to repeat this... Could it be some electrical issue? Could the NPP switch somehow cause an electrical issue thats messing with the O2 sensors? It doesn't make much sense. Unless the car thinks a fuse was blown and just goes into limp mode? Why the O2 sensor error?

Of course the dealer is no help.
"That's just how these cars are..." Seriously?

Sorry for the novel.
Thanks for the help.

EDIT:
HO2S Heater Control Circuit (Bank 2. Sensor 1) (Pending, Permanent. History)
HO2S Heater Control Circuit Low (Bank 2, Sensor 1) (Pending, Permanent. History)

The symptom for the above codes is the car runs rough, just like mine. Stumbling, hesitating, choking on acceleration.


Update: May 7. NPP switch is not the cause.

Since I expected the problem to be from the switch, I decided before I broke my car again, that I would rule out some lesser theories first.

100% stock, battery was pulled all last night, car ran great this morning.

On the drive home, I put the car in 5th gear at 2500rpm and did a 75% WOT.
Instant limp mode. Check engine light came on. Same code as before.
The car just shudders and hesitates and chokes like usual.

I don't believe this is user failure. I understand that lugging the engine is bad, but 5th gear at 2500rpm and 75% WOT = Instant Limp mode after one try and requires pulling the negative battery cable to fix it? Something isn't right.

Dealer wont help me. What else can I do?
I'm tempted to trade the car in on a non GM product.
And I dont think this is a rash decision.

The last 4 GM products I've owned:
2015 ZL1 knocked until I voided my warranty and had it tuned.
2017 Grand Sport, rod knock cyl#5, engine replaced under warranty, then it happened again.
2017 Z06, limp mode all the time, dealer wont help.
2018 ZL1 1LE, limp mode all the time, dealer wont help.

I think I've been more than forgiving! I think I've been dumb to retry GM so many times.
But I tell myself, how can one guy get so unlucky so many times, it must be me.

Except, every non-GM car I've had was great.

W. T. F.

[Alain]

I would think that whatever that switch is doing when you activate it, it is messing with the car.

I would just pull the fuse and don't get on the car while you're in your neighborhood. These cars are (too) quiet when you're driving around town. Just modulate your exhaust with your foot ;-)

[LT4Greg]

I agree with Alain. Just pull the fuse out and take your switch off the car. I pulled my fuse about a month ago and no problems for mine except the outer tailpipes are blacker than the inner pipes. No big deal for me!

[joe944]

Get rid of the switch. Honestly I couldn't even really tell the difference with the fuse pulled.

Get a catback if you want it to sound good.

[jjgi5150]

Hi angry,

Is there any possibility that the earlier accident you had and the subsequent repairs may have something to do with these problems? I'm wondering of they may have pinched a wire somewhere that might be causing all these issues???

Either way, good luck with all this and keep us posted...

JJ

[angryBits]

Originally Posted by jjgi5150

Hi angry,

Is there any possibility that the earlier accident you had and the subsequent repairs may have something to do with these problems? I'm wondering of they may have pinched a wire somewhere that might be causing all these issues???

Either way, good luck with all this and keep us posted...

JJ

Anything is possible, but I'd guess that is unrelated since I never had any work done on my Z06 and it experienced the exact same issue.

[angryBits]

I pulled the battery cable last night and this morning everything was great.

So on the drive home I'm going to flip the switch and see what happens. If it causes the problem then I know for sure.

Yeah I think I'm going to just pull the fuse out and leave it out.

[angryBits]

Update: NPP switch is not the cause.

Since I expected the problem to be from the switch, I decided before I broke my car again, that I would rule out some lesser theories first.

100% stock, battery was pulled all last night, car ran great this morning.

On the drive home, I put the car in 5th gear at 2500rpm and did a 75% WOT.
Instant limp mode. Check engine light came on. Same code as before.
The car just shudders and hesitates and chokes like usual.

I don't believe this is user failure. I understand that lugging the engine is bad, but 5th gear at 2500rpm and 75% WOT = Instant Limp mode after one try and requires pulling the negative battery cable to fix it? Something isn't right.

Dealer wont help me. What else can I do?
I'm tempted to trade the car in on a non GM product.
And I dont think this is a rash decision.

The last 4 GM products I've owned:
2015 ZL1 knocked until I voided my warranty and had it tuned.
2017 Grand Sport, rod knock cyl#5, engine replaced under warranty, then it happened again.
2017 Z06, limp mode all the time, dealer wont help.
2018 ZL1 1LE, limp mode all the time, dealer wont help.

I think I've been more than forgiving! I think I've been dumb to retry GM so many times.
But I tell myself, how can one guy get so unlucky so many times, it must be me.

Except, every non-GM car I've had was great.

W. T. F.

[rlarsen462]

Originally Posted by angryBits

Update: NPP switch is not the cause.

Since I expected the problem to be from the switch, I decided before I broke my car again, that I would rule out some lesser theories first.

100% stock, battery was pulled all last night, car ran great this morning.

On the drive home, I put the car in 5th gear at 2500rpm and did a 75% WOT.
Instant limp mode. Check engine light came on. Same code as before.
The car just shudders and hesitates and chokes like usual.

I don't believe this is user failure. I understand that lugging the engine is bad, but 5th gear at 2500rpm and 75% WOT = Instant Limp mode after one try and requires pulling the negative battery cable to fix it? Something isn't right.

Dealer wont help me. What else can I do?
I'm tempted to trade the car in on a non GM product.
And I dont think this is a rash decision.

The last 4 GM products I've owned:
2015 ZL1 knocked until I voided my warranty and had it tuned.
2017 Grand Sport, rod knock cyl#5, engine replaced under warranty, then it happened again.
2017 Z06, limp mode all the time, dealer wont help.
2018 ZL1 1LE, limp mode all the time, dealer wont help.

I think I've been more than forgiving! I think I've been dumb to retry GM so many times.
But I tell myself, how can one guy get so unlucky so many times, it must be me.

Except, every non-GM car I've had was great.

W. T. F.

Wow. I don't think I could blame you moving on at this point. It's weird that no one else seems to be having the same kind of issues (especially with back to back LT4 cars...).

This is my first GM performance product an so far so good at about 600 miles but I'm definitely probably doing too much tinkering already and as I said in your other thread also chasing throttle response weirdness. No codes or limp mode ever though.

[kwav8r]

What do you mean that the dealer won't help you?

What you're describing certainly sounds like an electrical issue.

Have all of the warranty repairs (i.e. wiring harness/bundles) on the car been completed?

If the dealer has effectively voided the warranty then I suggest you get it tuned. Every ZL1 owner I've heard that had a tune done absolutely loves the result.

[Scottyz]

Dealer won’t help you????
That seems odd even if you jacked around with the NPP fuse.
Hey man she’s junk. Get rid of it. Adios
Good luck on your next beast. They are all fun.

[angryBits]

Originally Posted by kwav8r

What do you mean that the dealer won't help you?

What you're describing certainly sounds like an electrical issue.

Have all of the warranty repairs (i.e. wiring harness/bundles) on the car been completed?

If the dealer has effectively voided the warranty then I suggest you get it tuned. Every ZL1 owner I've heard that had a tune done absolutely loves the result.

Originally Posted by Scottyz

Dealer won’t help you????
That seems odd even if you jacked around with the NPP fuse.
Hey man she’s junk. Get rid of it. Adios
Good luck on your next beast. They are all fun.

I admit I have not tried yet with my ZL1, but I went through this exact same thing, same symptoms same codes, same story with my Z06 and they literally said: "That's just how these cars are." Multiple dealers similar response. I was so upset I sold my Z06. I didn't want to tune it because the 2017 Grand Sport I had prior to my Z06 had an engine failure so it was too fresh for me to risk voiding my warranty.

I never imagined I'd get the exact same thing again with my ZL1.
However I did **JUST NOW** find this post about a recall that may have affected both my Z06 and ZL1: https://www.camaro6.com/forums/showthread.php?t=527188

I'm going to try this.

[17CamaroZL1]

Originally Posted by angryBits

I admit I have not tried yet with my ZL1, but I went through this exact same thing, same symptoms same codes, same story with my Z06 and they literally said: "That's just how these cars are." Multiple dealers similar response. I was so upset I sold my Z06. I didn't want to tune it because the 2017 Grand Sport I had prior to my Z06 had an engine failure so it was too fresh for me to risk voiding my warranty.

I never imagined I'd get the exact same thing again with my ZL1.
However I did **JUST NOW** find this post about a recall that may have affected both my Z06 and ZL1: https://www.camaro6.com/forums/showthread.php?t=527188

I'm going to try this.

GM has added this same fix to 3 or 4 different areas of the wiring on our cars. Anytime the car is brought to the dealer, they are supposed to add the conduit and protective tape to any of these areas that hasn't been addressed yet. Pretty sure my dealer has done this 3 different times as GM has added more areas of concern and I've had the car in for oil changes or other service. If you haven't taken it in yet, definitely try that first. Good luck. Hope to hear good results.