Weird misfire problem - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Rob-1SS · 04-18-2023, 03:21 PM

So I've been having an issue with some cylinders not firing particularly 3, 5, 7. I put in new spark plugs (twice) and same issue. I swapped ignition coils and tried some new ones and wires. Same issue. I removed and cleaned the injectors and didn't plug in cylinder number 1 all the way however when I turned it on cylinders 7 and 5 were firing and 1 and 3 were not. I then plugged injector 1 back in and unplugged cylinder 3 and cylinder 1 and five were firing. I'm really not sure what this is possibly wiring? ECM? Battery test great. I am in a state of confusion and rage.

What I'm running:
1SS
Cam (forget the size)
LT
Magnuson 2650 (6lbs boost) has been tuned.
ZL1 fuel Pump

Rob-1SS · 04-18-2023, 04:32 PM

Also, no codes and o2 and MAF sensors have been replaced. One thing I noticed was the battery's negative terminal was a little loose. I've tightened it but the problem persists.

gtstorey · 04-18-2023, 04:41 PM

Sounds like a wiring issue. When you say you are plugging and unplugging injectors and this makes it fire, do you mean it runs on those cylinders or the plugs actually spark.

Rob-1SS · 04-18-2023, 05:31 PM

Quote:

Originally Posted by gtstorey

Sounds like a wiring issue. When you say you are plugging and unplugging injectors and this makes it fire, do you mean it runs on those cylinders or the plugs actually spark.

No sparks. Normally right now cylinders 3,5,7 won't fire. If I unplug the fuel injector to number 1 then cylinder 5 and 7 fire. If I plug them all in and unplug number 3 cylinders 1 and 5 (I think it was 5, that or 7) fire up. I'm not going to rule out the supernatural just yet either.

gtstorey · 04-19-2023, 08:58 AM

Still sounds like a wiring issue or an ECM. And by wiring, I'm including grounding issues. And by ECM, I'm including problems within the ECM with it's grounding drivers/bus.

But in particular it sounds like a short between the injector and coil wirings so that when injectors are plugged in, it's "stealing" the signal for the coil to fire.

Or you just have a loose connection/broken wires that all of this plugging and unplugging causes to make contact.

Aqua Blue RS/SS · 04-19-2023, 11:20 AM

Quote:

Originally Posted by gtstorey

Still sounds like a wiring issue or an ECM. And buy wiring, I'm including grounding issues. And by ECM, I'm including problems within the ECM with it's grounding drivers/bus.

But in particular it sounds like a short between the injector and coil wirings so that when injectors are plugged in, it's "stealing" the signal for the coil to fire.

Or you just have a loose connection/broken wires that all of this plugging and unplugging causes to make contact.

Exactly what I was gonna say, you’ve got wiring/ground issues somewhere.

Rob-1SS · 04-19-2023, 12:24 PM

Quote:

Originally Posted by gtstorey

Still sounds like a wiring issue or an ECM. And buy wiring, I'm including grounding issues. And by ECM, I'm including problems within the ECM with it's grounding drivers/bus.

But in particular it sounds like a short between the injector and coil wirings so that when injectors are plugged in, it's "stealing" the signal for the coil to fire.

Or you just have a loose connection/broken wires that all of this plugging and unplugging causes to make contact.

Thanks, thats what I'm thinking to, wiring or ECM. I'll be getting some needle nose probes (ones i have are too big) for my meter today but I work nights so I'll be getting up early and spending my off time messing with this lol.

acutron42 · 04-19-2023, 05:40 PM

Here are the injector & 1-3-5-7 coil diagrams if it helps any.

Rob-1SS · 04-19-2023, 05:51 PM

Quote:

Originally Posted by acutron42

Here are the injector & 1-3-5-7 coil diagrams if it helps any.

Yes ty!

gtstorey · 04-19-2023, 06:01 PM

I would start by tracing out/inspecting circuit 5291 since the injectors and coils have that in common.

acutron42 · 04-19-2023, 06:25 PM

Your welcome! Let us know what you find.

acutron42 · 04-20-2023, 06:34 AM

Start with the J113 connector. When I click on it the whole circuit lights up all of your problem areas. I will try to get some full pages posted @ work today.

Rob-1SS · 04-20-2023, 07:12 PM

Quote:

Originally Posted by acutron42

Start with the J113 connector. When I click on it the whole circuit lights up all of your problem areas. I will try to get some full pages posted @ work today.

Thanks again. Didn't find anything today but I'll try again over the weekend. If I still can't figure it out I'm taking it to a friend's repair shop Monday.

Rob-1SS · 04-24-2023, 11:05 PM

Gave up, it's at a friend's shop. I'll still post an update on what they find in case anyone else has a similar issue in the future.

04-18-2023, 03:21 PM	#1
Rob-1SS Drives: Chevy Camaro 1SS Join Date: Apr 2023 Location: Florida Posts: 10	Weird misfire problem So I've been having an issue with some cylinders not firing particularly 3, 5, 7. I put in new spark plugs (twice) and same issue. I swapped ignition coils and tried some new ones and wires. Same issue. I removed and cleaned the injectors and didn't plug in cylinder number 1 all the way however when I turned it on cylinders 7 and 5 were firing and 1 and 3 were not. I then plugged injector 1 back in and unplugged cylinder 3 and cylinder 1 and five were firing. I'm really not sure what this is possibly wiring? ECM? Battery test great. I am in a state of confusion and rage. What I'm running: 1SS Cam (forget the size) LT Magnuson 2650 (6lbs boost) has been tuned. ZL1 fuel Pump

04-19-2023, 08:58 AM	#5
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,450	Still sounds like a wiring issue or an ECM. And by wiring, I'm including grounding issues. And by ECM, I'm including problems within the ECM with it's grounding drivers/bus. But in particular it sounds like a short between the injector and coil wirings so that when injectors are plugged in, it's "stealing" the signal for the coil to fire. Or you just have a loose connection/broken wires that all of this plugging and unplugging causes to make contact. Last edited by gtstorey; 04-19-2023 at 12:53 PM. Reason: typo fix

04-19-2023, 05:40 PM	#8
acutron42 Drives: 2013 Camaro 2SS AGM Join Date: Apr 2020 Location: WNY Posts: 957	Here are the injector & 1-3-5-7 coil diagrams if it helps any. Attached Images __________________ 2013 2SS GPI built & tuned 415, spec'd by Andrew Cammer. GPI ported intake/tb/heads, Tooley springs, CHE trunnions, Callies rotating assembly, Diamond pistons, GPI SS3 VVT, ATI 10% ud damper, Circle D 3800, Kooks ceramic coated lt's with green cats, Mishimoto rad & oil cooler, Derale trans cooler, Holley efi rails. DSS driveshaft, trutrac with 3.91's, G-Force renegades, Hendrix solid cradle bushings Bmr: poly diff bushings, Strange adjustable coilovers, sub frame connectors, ZL1 npps, controlled with a vac pump & mac boost control solenoid.

04-19-2023, 06:25 PM	#11
acutron42 Drives: 2013 Camaro 2SS AGM Join Date: Apr 2020 Location: WNY Posts: 957	Your welcome! Let us know what you find. __________________ 2013 2SS GPI built & tuned 415, spec'd by Andrew Cammer. GPI ported intake/tb/heads, Tooley springs, CHE trunnions, Callies rotating assembly, Diamond pistons, GPI SS3 VVT, ATI 10% ud damper, Circle D 3800, Kooks ceramic coated lt's with green cats, Mishimoto rad & oil cooler, Derale trans cooler, Holley efi rails. DSS driveshaft, trutrac with 3.91's, G-Force renegades, Hendrix solid cradle bushings Bmr: poly diff bushings, Strange adjustable coilovers, sub frame connectors, ZL1 npps, controlled with a vac pump & mac boost control solenoid.

04-20-2023, 06:34 AM	#12
acutron42 Drives: 2013 Camaro 2SS AGM Join Date: Apr 2020 Location: WNY Posts: 957	Start with the J113 connector. When I click on it the whole circuit lights up all of your problem areas. I will try to get some full pages posted @ work today. Attached Images __________________ 2013 2SS GPI built & tuned 415, spec'd by Andrew Cammer. GPI ported intake/tb/heads, Tooley springs, CHE trunnions, Callies rotating assembly, Diamond pistons, GPI SS3 VVT, ATI 10% ud damper, Circle D 3800, Kooks ceramic coated lt's with green cats, Mishimoto rad & oil cooler, Derale trans cooler, Holley efi rails. DSS driveshaft, trutrac with 3.91's, G-Force renegades, Hendrix solid cradle bushings Bmr: poly diff bushings, Strange adjustable coilovers, sub frame connectors, ZL1 npps, controlled with a vac pump & mac boost control solenoid.

04-18-2023, 04:32 PM	#2
Rob-1SS Drives: Chevy Camaro 1SS Join Date: Apr 2023 Location: Florida Posts: 10	Also, no codes and o2 and MAF sensors have been replaced. One thing I noticed was the battery's negative terminal was a little loose. I've tightened it but the problem persists.

04-18-2023, 04:41 PM	#3
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,450	Sounds like a wiring issue. When you say you are plugging and unplugging injectors and this makes it fire, do you mean it runs on those cylinders or the plugs actually spark.

04-19-2023, 06:01 PM	#10
gtstorey Drives: 2010 Camaro SS2,L99, LSA SC Join Date: Aug 2017 Location: Huntsville, AL Posts: 2,450	I would start by tracing out/inspecting circuit 5291 since the injectors and coils have that in common.

04-24-2023, 11:05 PM	#14
Rob-1SS Drives: Chevy Camaro 1SS Join Date: Apr 2023 Location: Florida Posts: 10	Gave up, it's at a friend's shop. I'll still post an update on what they find in case anyone else has a similar issue in the future.