Persistent Misfire cylinder 3

[Nap73]

P0353, as James stated, is a coil specific code. Your mechanic swapped coils and it stayed with #3. I think you stated that the mechanic even swapped injectors and it stayed with #3, but that wasn’t clear. I would make sure I have thoroughly checked the wiring harness going to your coils to make sure they don’t have any corrosion or possible loose connections or damage before going any further. If that checks out, then as the others have indicated, you will need to deal with your ECM.

1-Mechanic swapped coils not injectors and the issue stayed with # 3.

2-We also inspected / manipulated the wiring to see if the misfire could be triggered that way. But nothing.

I’m almost to the point that I change the wiring out anyway. It’s cheap and easy. Only thing stopping me is the possibility it won’t fix the issue.

There is no test to verify that the ECM is at fault here? From what I understand there are “drivers” that control the current sent to the coils correct?









Sent from my iPhone using Tapatalk

 

[kbuskill]

1-Mechanic swapped coils not injectors and the issue stayed with # 3.

2-We also inspected / manipulated the wiring to see if the misfire could be triggered that way. But nothing.

I’m almost to the point that I change the wiring out anyway. It’s cheap and easy. Only thing stopping me is the possibility it won’t fix the issue.

There is no test to verify that the ECM is at fault here? From what I understand there are “drivers” that control the current sent to the coils correct?


Sent from my iPhone using Tapatalk

The ECM is the driver. It pulses the ground wire of the coil when it wants the coil to spark. The other wire going to the coil will be 12v positive all the time when the ignition is on.

Use a volt meter and check for 12v on one of the wires at the coil. If you don't have 12v on one of them with the ignition on then that is your problem.

If you have 12V on one wire at the coil then use the volt meter on the Hertz scale to look for a pulsing signal on the coils ground wire while the engine is running.

You could also check the same "ground" wire on the coil for continuity to ground with the engine off. If you have continuity to ground then you have a short to ground and that is your problem.
You could also check it for voltage as it could be shorted to voltage instead.

You could also unplug the ECM and check for continuity between the same wire on the coil and which ever pin it connects to on the ECM. If you don't have continuity then you have a break in the wire somewhere and that is your problem.

 

[swathdiver]

1-Mechanic swapped coils not injectors and the issue stayed with # 3.

2-We also inspected / manipulated the wiring to see if the misfire could be triggered that way. But nothing.

I’m almost to the point that I change the wiring out anyway. It’s cheap and easy. Only thing stopping me is the possibility it won’t fix the issue.

There is no test to verify that the ECM is at fault here? From what I understand there are “drivers” that control the current sent to the coils correct?









Sent from my iPhone using Tapatalk

I shared with you how to do it, it's the process of elimination. If the first two check out ok, it can only be the ECM.

 

[Nap73]

I wouldn't jump to replacing the ecm unless all other parts checked first, the ecm is the last resort and yes it would need to be flashed. you would be better of investing the money in a tech2 then you can have dealer level diagnostics in your own hands and it would only cost you $40 to flash the ecm yourself if it came down to that, the tech2 will pay for it's self over time.

I’ve got my eye on a Tech2. What do I need to look for?


Sent from my iPhone using Tapatalk

 

[HiHoeSilver]

I’ve got my eye on a Tech2. What do I need to look for?


Sent from my iPhone using Tapatalk

Software 33.004

 

[Doubeleive]

I’ve got my eye on a Tech2. What do I need to look for?


Sent from my iPhone using Tapatalk

I would just look for one from a usa seller in case there was any issue with it upon receipt easier to send one back in the usa than to china

 

[Nap73]

I would just look for one from a usa seller in case there was any issue with it upon receipt easier to send one back in the usa than to china

It’s a US based seller. He’s looking for $300 for it. More than likely buying it. Just want to make sure it’s running the correct software.


Sent from my iPhone using Tapatalk

 

[Doubeleive]

It’s a US based seller. He’s looking for $300 for it. More than likely buying it. Just want to make sure it’s running the correct software.


Sent from my iPhone using Tapatalk

the last software update was done quit a while ago unless it's a old used one pretty sure anything "new" on the market will have the current software (or should anyway)

 

[Nap73]

Software 33.004

Guy doesn’t know how to check what software it’s running. What do I tell him ?

Thanks


Sent from my iPhone using Tapatalk

 

[HiHoeSilver]

Guy doesn’t know how to check what software it’s running. What do I tell him ?

Thanks


Sent from my iPhone using Tapatalk

Boot up screen, I believe. @swathdiver @Doubeleive

 

[Fless]

Have him power it up with the AC converter or the OBD port in the truck, after a short diagnostic few seconds it will display the software version at the bottom of the screen. Latest is 33.004.

EDIT: like this

Make sure you're getting the Candi module and all the connectors. Is it new or used? Come with a case?

 

[thompsoj22]

Guy doesn’t know how to check what software it’s running. What do I tell him ?

Thanks


Sent from my iPhone using Tapatalk

"RUN" Find another seller! There are so many "new" knockoffs out there that it just dosent make sense to purchase from someone that dosent know what he is selling? Also i bought mine from aliexpress from china, $350 shipped fedex to my door. However if it ever craps i would not consider trying to return it, to much involved so a state side vendor is the way to go.

 

[Nap73]

Truck went from last Saturday to this Friday throwing zero codes. In that time it was driven many miles. On Friday my wife got the P0303 & P0353 codes again. I cleared the codes put some sea foam in the tank and continued driving code free.

It’s worth it noting that those codes only seem to come up even intermittent when the truck has 1/4 tank of gas or less.

Now I know the most knowledgeable guys here have all been saying from the beginning it’s either the coil wires or the ECM. Question is I have to take a 2 1/2 trip upstate today. And on Monday have to go to Manhattan twice. On a long shot I ordered the AC delco coil wires from Amazon and they will be here tomorrow.

After swapping these out the only other thing is the ECM or a short somewhere correct ?

Also I can not find a video on how to instal the coil wires. Can anyone direct Me to one.

Thanks




Sent from my iPhone using Tapatalk

 

[Nap73]

Truck went from last Saturday to this Friday throwing zero codes. In that time it was driven many miles. On Friday my wife got the P0303 & P0353 codes again. I cleared the codes put some sea foam in the tank and continued driving code free.

It’s worth it noting that those codes only seem to come up even intermittent when the truck has 1/4 tank of gas or less.

Now I know the most knowledgeable guys here have all been saying from the beginning it’s either the coil wires or the ECM. Question is I have to take a 2 1/2 trip upstate today. And on Monday have to go to Manhattan twice. On a long shot I ordered the AC delco coil wires from Amazon and they will be here tomorrow.

After swapping these out the only other thing is the ECM or a short somewhere correct ?

Also I can not find a video on how to instal the coil wires. Can anyone direct Me to one.

Thanks




Sent from my iPhone using Tapatalk

These are what I purchased

ACDelco 357A GM Original Equipment Ignition Coil Wire https://www.amazon.com/dp/B001KSAQNM/ref=cm_sw_r_cp_api_i_dh76DbF5W3QDN



Sent from my iPhone using Tapatalk

 

[Nap73]

Have him power it up with the AC converter or the OBD port in the truck, after a short diagnostic few seconds it will display the software version at the bottom of the screen. Latest is 33.004.

EDIT: like this

View attachment 236036

Make sure you're getting the Candi module and all the connectors. Is it new or used? Come with a case?

It’s used with the Candi module and connectors + the case.


Sent from my iPhone using Tapatalk

 

[Nap73]

It’s used with the Candi module and connectors + the case.


Sent from my iPhone using Tapatalk

Changed out the wire harness that connects to the coils. Was pretty simple/self explanatory. Just took a 40 min drive and no misfire/codes. I’ll be driving back and forth to Manhattan twice tomorrow about 180 miles in total. If I make it with no issue then that was the problem if not I’ll buy an ECM.

Sent from my iPhone using Tapatalk

 

[Nap73]

Changed out the wire harness that connects to the coils. Was pretty simple/self explanatory. Just took a 40 min drive and no misfire/codes. I’ll be driving back and forth to Manhattan twice tomorrow about 180 miles in total. If I make it with no issue then that was the problem if not I’ll buy an ECM.

Sent from my iPhone using Tapatalk

Sent from my iPhone using Tapatalk

 

[Nap73]

Sent from my iPhone using Tapatalk

Anyone use this service?

http://alldatadiy.com/?gclid=CjwKCA...Fho9BoDiZtUyX0S1bAogfOUgoJLpaaLBoCaUwQAvD_BwE

Also what’s everyone think of Delphi parts ?


Sent from my iPhone using Tapatalk

 

[wjburken]

Changed out the wire harness that connects to the coils. Was pretty simple/self explanatory. Just took a 40 min drive and no misfire/codes. I’ll be driving back and forth to Manhattan twice tomorrow about 180 miles in total. If I make it with no issue then that was the problem if not I’ll buy an ECM.

Sent from my iPhone using Tapatalk

I hope this is the end of your issues my friend.

 

[Nap73]

I hope this is the end of your issues my friend.

So do I Brother. There will always be a little something to do though. Thing is the more I do myself the more I learn. Parts are a lot cheaper than labor.


Sent from my iPhone using Tapatalk