$20 to whoever figures this out - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

L99problems · 08-14-2021, 12:53 AM

I’m not joking. I’m at that point where I need some ideas..

Centrifugal setup, 388CI motor on e85. Bank 2 O2 sensor reads lean almost all the time. Seems lazy and doesn’t switch properly. Lives around 55-60mv at idle and will switch lazily while cruising but hover around 55mv. Bank 1 seems to switch properly if anything a little on the rich side. Car has a miss or stumble at low rpm high load and seems to misfire a bit on cold start. I’ve attached a log and you can see the miss around 3800-4000 rpm the bank 2 sensor stays lean while the bank 1 sensor switches up and down.

So far I have tried multiple sets of plugs (br7ef gapped .022) and wires. Two sets of coil packs, two sets of GM 02 sensors, two different extension harnesses. I’ve gone over all the grounds and sanded them and re-attached. Checked the injector harness with a noid light. Visually inspected the engine harness for broken or bare wires. Pulled both valve covers to check for a broken valve spring. Injectors were flow tested about 1500 miles ago but I haven’t ruled them out quite yet. No misfire codes or any CEL of any kind.

Open to new ideas.. if nothing else works I will pull the injectors and have them tested again. My tuner and I both feel it’s an ignition issue but I have been wrong once or twice before. Thanks for any input

AlanRubin · 08-14-2021, 02:25 AM

Gap seems too small for that application, not being boosted. IF you are, it's still
too small. .028 is a good boosted gap setting. You can also run a hotter plug
if you plan on being E85 exclusive. 0.33 gap not boosted.

Running E85 is tricky without the sensor kit, or an ECU tuned for E85. You need
more E85 to do the same job as regular fuel. If you do not have a check engine
light, the ECU doesn't see a problem. It will code out if stuck lean or stuck rich.
The voltages are supposed to bounce up and down. IF they stay high, or low too
long, is when they're rich or lean.

If you go back to RUG, and you don't see these conditions, it is a direct relation
to the E85 fuel mixture.

Not looking to make $20, just some observations. I run E85 on my V6, and I
do not have any issues, motor being stock.

We need more information, like long-tube headers, and all that. We need a
complete list of what the motor has on it to help. Tuned or not, and so forth.

acutron42 · 08-14-2021, 08:35 AM

Possible intake leak on bank 2? It is unlikely but just throwing it out there. No cel or specific cylinder misfire reported is interesting. I am sure you will get an answer here.

ADVMax · 08-14-2021, 08:42 AM

So what if the 02 sensor is sending bad data? Has that been checked? Can give same diag results as an air leak in a lot of cases.

EDIT: re read and see at least 2 02 sensor swaps. Reading are hard.

EDIT EDIT: see if there’s a plug wire touching an 02 sensor wire somewhere on that side of the engine. Simple magnetic inductance can cause weird stuff.

silversleeper · 08-14-2021, 09:56 AM

Any burned cats?
I think it's not in the ignition as you suspect. I would look harder at ground connections first. Find the post that lists them, or i'll try to post a pic someone provided.
I lean (oops pun there) towards injector system issues, could be a bad ground, not the injectors themselves as you've already tested.
Also on that lean note, there isn't any injector info on your hp tuner pic, again could be a hint. Could be simply wrong pid selected or something, but get that sorted out so it shows too. Someone smart here can figure it out with enough info (I'm only semi-smart).
Could be something like injector driver in the ecu, but if grounds inadequate that could cause that too, not necessarily a bad ecu. So make sure you're checking the other ground connections that help ecu and injectors not only big ones for the starter. I think someone mentioned a bad ground either near the ecu or fuse box so make sure. Harness pinched and wire messed up is also possible especialy after engine R and R. Harness and ecu connections good.

L99problems · 08-14-2021, 12:13 PM

Thanks to everyone who has responded so far.

I’m going to try another set of plugs at 0.26 gap which is what the Br7ef plugs come pre-gapped at. I would think if it was the gap it would do it on both banks instead of just bank 2. I am going to go over all my grounds again. A harness issue will be very difficult to find and if it comes to it I may just buy a complete new engine harness. Injector issue is a very real possibility at this point as I’ve changed pretty much everything in the ignition system with no avail. I may swap the injectors from bank to bank to see if the lean condition follows.

acutron42 · 08-14-2021, 12:24 PM

I have an alldata subscription & if you need any diagrams let me know.

silversleeper · 08-14-2021, 01:07 PM

Still can't see fuel pressure or injector duty cycle info on the log. I'd start there after looking over grounds to make sure they are all there and no visible broken wires.

L99problems · 08-14-2021, 04:02 PM

Yes I will try another log to see if I can get fuel pressure and injector data. A vacuum leak on that bank would show up in the STFT’s would it not? Fuel trims seem to be in spec.

TheFlyingBananaSS · 08-14-2021, 06:28 PM

Intermittent short or open in ecm.

acutron42 · 08-14-2021, 06:33 PM

Quote:

Originally Posted by TheFlyingBananaSS

Intermittent short or open in ecm.

Could be that bank is reporting but the ecm is not correcting.

L99problems · 08-14-2021, 08:39 PM

Update:

Something I forgot to add. The first attempt at solving this issue was to swap the passenger side coil packs with a set of known good set of coil packs. All I did was swap the packs and all of the sudden the car would not start. Long crank and sputter to life and die. After a few tries it will start real rough and eventually run. Come to find out cylinders 4,8, and 5 are not firing on a cold start. Coincidence? Or possibly something to do with messing around on the passenger side wiring harness? Since then I have tried all of the basics minus swapping the injectors around. The problem was only the stumble/breakup under load but it always cold started just fine.

prod · 08-14-2021, 09:08 PM

I think injectors would be the next thing to check. Are they new?
Try switching them around or get them tested for flow and pattern.

L99problems · 08-14-2021, 10:09 PM

Another update:

Cylinder 5 has been a trouble cylinder on cold starts and is the easiest to access. I swapped cylinder 5 and 3 injectors. I will have to let the car sit and cool for a while to see if it effects cold start. Changed plugs yet again with a 0.26 gap and triple checked grounds. Car started and idled like garbage and cleaned up after about 10 seconds. Took the car for a spin around the block and it runs even worse. Bank 2 O2 sensor is pretty much flatlined at this point. Not really moving at all and stuck between 20-60mv. Any load at all and the car breaks up and runs poorly. Something is not happy on bank 2 but I’ve basically tried everything at this point. I’ve attached another photo of the log and you can see bank 2 dead.

08-14-2021, 12:53 AM	#1
L99problems Drives: 2010 Camaro 2ss Join Date: Mar 2018 Location: Gilbert, AZ Posts: 59	$20 to whoever figures this out I’m not joking. I’m at that point where I need some ideas.. Centrifugal setup, 388CI motor on e85. Bank 2 O2 sensor reads lean almost all the time. Seems lazy and doesn’t switch properly. Lives around 55-60mv at idle and will switch lazily while cruising but hover around 55mv. Bank 1 seems to switch properly if anything a little on the rich side. Car has a miss or stumble at low rpm high load and seems to misfire a bit on cold start. I’ve attached a log and you can see the miss around 3800-4000 rpm the bank 2 sensor stays lean while the bank 1 sensor switches up and down. So far I have tried multiple sets of plugs (br7ef gapped .022) and wires. Two sets of coil packs, two sets of GM 02 sensors, two different extension harnesses. I’ve gone over all the grounds and sanded them and re-attached. Checked the injector harness with a noid light. Visually inspected the engine harness for broken or bare wires. Pulled both valve covers to check for a broken valve spring. Injectors were flow tested about 1500 miles ago but I haven’t ruled them out quite yet. No misfire codes or any CEL of any kind. Open to new ideas.. if nothing else works I will pull the injectors and have them tested again. My tuner and I both feel it’s an ignition issue but I have been wrong once or twice before. Thanks for any input Attached Images

08-14-2021, 09:56 AM	#5
silversleeper Big Crow Drives: '13 ZL1 Join Date: Mar 2017 Location: California Posts: 1,483	Any burned cats? I think it's not in the ignition as you suspect. I would look harder at ground connections first. Find the post that lists them, or i'll try to post a pic someone provided. I lean (oops pun there) towards injector system issues, could be a bad ground, not the injectors themselves as you've already tested. Also on that lean note, there isn't any injector info on your hp tuner pic, again could be a hint. Could be simply wrong pid selected or something, but get that sorted out so it shows too. Someone smart here can figure it out with enough info (I'm only semi-smart). Could be something like injector driver in the ecu, but if grounds inadequate that could cause that too, not necessarily a bad ecu. So make sure you're checking the other ground connections that help ecu and injectors not only big ones for the starter. I think someone mentioned a bad ground either near the ecu or fuse box so make sure. Harness pinched and wire messed up is also possible especialy after engine R and R. Harness and ecu connections good. Attached Images

08-14-2021, 06:28 PM	#10
TheFlyingBananaSS Evil Genius of Chevrolet Drives: 2017 Z06, 2019 XTS, 2013 SS Join Date: Feb 2017 Location: New York Posts: 3,260	Intermittent short or open in ecm. __________________ GPI SS2 VVT cam, ECS Novi 1500 supercharger, Corsa Extreme, Detroit Speed and BMR suspension, Circle D triple disc, Melling oil pump, LS2 chain tensioner, ATI 10% UD, DSX E85 kit, High Energy coils, BTR springs, LS2 Lifter trays, Titanium retainers, hardened push rods, FIC 1000 injectors, ZL1 pump, Mighty Mouse catch can, AEM gauges, Tial BOV, Richmond 3.91 gears, Custom gauge bezels, Speed Engineering headers, Stainless Works HF cats, DSX Aux pump, 710rwhp on E85.

08-14-2021, 10:09 PM	#14
L99problems Drives: 2010 Camaro 2ss Join Date: Mar 2018 Location: Gilbert, AZ Posts: 59	Another update: Cylinder 5 has been a trouble cylinder on cold starts and is the easiest to access. I swapped cylinder 5 and 3 injectors. I will have to let the car sit and cool for a while to see if it effects cold start. Changed plugs yet again with a 0.26 gap and triple checked grounds. Car started and idled like garbage and cleaned up after about 10 seconds. Took the car for a spin around the block and it runs even worse. Bank 2 O2 sensor is pretty much flatlined at this point. Not really moving at all and stuck between 20-60mv. Any load at all and the car breaks up and runs poorly. Something is not happy on bank 2 but I’ve basically tried everything at this point. I’ve attached another photo of the log and you can see bank 2 dead. Attached Images

08-14-2021, 02:25 AM	#2
AlanRubin Banned Drives: 2010 LS Join Date: Feb 2021 Location: Pgh Posts: 411	Gap seems too small for that application, not being boosted. IF you are, it's still too small. .028 is a good boosted gap setting. You can also run a hotter plug if you plan on being E85 exclusive. 0.33 gap not boosted. Running E85 is tricky without the sensor kit, or an ECU tuned for E85. You need more E85 to do the same job as regular fuel. If you do not have a check engine light, the ECU doesn't see a problem. It will code out if stuck lean or stuck rich. The voltages are supposed to bounce up and down. IF they stay high, or low too long, is when they're rich or lean. If you go back to RUG, and you don't see these conditions, it is a direct relation to the E85 fuel mixture. Not looking to make $20, just some observations. I run E85 on my V6, and I do not have any issues, motor being stock. We need more information, like long-tube headers, and all that. We need a complete list of what the motor has on it to help. Tuned or not, and so forth.

08-14-2021, 08:35 AM	#3
acutron42 Drives: 2013 Camaro 2SS AGM Join Date: Apr 2020 Location: WNY Posts: 732	Possible intake leak on bank 2? It is unlikely but just throwing it out there. No cel or specific cylinder misfire reported is interesting. I am sure you will get an answer here.

08-14-2021, 08:42 AM	#4
ADVMax Sporting Foole Drives: 2010 Camaro SS Join Date: Sep 2019 Location: Alabama Posts: 500	So what if the 02 sensor is sending bad data? Has that been checked? Can give same diag results as an air leak in a lot of cases. EDIT: re read and see at least 2 02 sensor swaps. Reading are hard. EDIT EDIT: see if there’s a plug wire touching an 02 sensor wire somewhere on that side of the engine. Simple magnetic inductance can cause weird stuff.

08-14-2021, 12:13 PM	#6
L99problems Drives: 2010 Camaro 2ss Join Date: Mar 2018 Location: Gilbert, AZ Posts: 59	Thanks to everyone who has responded so far. I’m going to try another set of plugs at 0.26 gap which is what the Br7ef plugs come pre-gapped at. I would think if it was the gap it would do it on both banks instead of just bank 2. I am going to go over all my grounds again. A harness issue will be very difficult to find and if it comes to it I may just buy a complete new engine harness. Injector issue is a very real possibility at this point as I’ve changed pretty much everything in the ignition system with no avail. I may swap the injectors from bank to bank to see if the lean condition follows.

08-14-2021, 12:24 PM	#7
acutron42 Drives: 2013 Camaro 2SS AGM Join Date: Apr 2020 Location: WNY Posts: 732	I have an alldata subscription & if you need any diagrams let me know.

08-14-2021, 01:07 PM	#8
silversleeper Big Crow Drives: '13 ZL1 Join Date: Mar 2017 Location: California Posts: 1,483	Still can't see fuel pressure or injector duty cycle info on the log. I'd start there after looking over grounds to make sure they are all there and no visible broken wires.

08-14-2021, 04:02 PM	#9
L99problems Drives: 2010 Camaro 2ss Join Date: Mar 2018 Location: Gilbert, AZ Posts: 59	Yes I will try another log to see if I can get fuel pressure and injector data. A vacuum leak on that bank would show up in the STFT’s would it not? Fuel trims seem to be in spec.

08-14-2021, 08:39 PM	#12
L99problems Drives: 2010 Camaro 2ss Join Date: Mar 2018 Location: Gilbert, AZ Posts: 59	Update: Something I forgot to add. The first attempt at solving this issue was to swap the passenger side coil packs with a set of known good set of coil packs. All I did was swap the packs and all of the sudden the car would not start. Long crank and sputter to life and die. After a few tries it will start real rough and eventually run. Come to find out cylinders 4,8, and 5 are not firing on a cold start. Coincidence? Or possibly something to do with messing around on the passenger side wiring harness? Since then I have tried all of the basics minus swapping the injectors around. The problem was only the stumble/breakup under load but it always cold started just fine.

08-14-2021, 09:08 PM	#13
prod Drives: HHR Join Date: Dec 2015 Location: GTA ON CA Posts: 451	I think injectors would be the next thing to check. Are they new? Try switching them around or get them tested for flow and pattern.