2G P0302

[OldGregg]

Hey guys,

Having an odd cylinder 2 misfire that’s intermittent. Pulls code on start up and revs pretty sluggish. Turn it off and turn back on and no misfire. Does this sound like a plug or coil pack issue? Mechanic said there’s brand new plugs in there (have yet to pull them) and I recently put some new ngk8100 wires in which fixed some power-band sputtering. Any ideas?

 

[pauleyman]

Hey guys,

Having an odd cylinder 2 misfire that’s intermittent. Pulls code on start up and revs pretty sluggish. Turn it off and turn back on and no misfire. Does this sound like a plug or coil pack issue? Mechanic said there’s brand new plugs in there (have yet to pull them) and I recently put some new ngk8100 wires in which fixed some power-band sputtering. Any ideas?

Biggest clue is you just touched something. Go back over your work. Make sure wires are seated well on both ends, Check coil towers for cracks etc. Check your new wires for arc spots. Just because they're new doesn't mean anything. It's a different part than what you had.

 

[OldGregg]

Hey guys,

Troubleshooting a P0302 cyl 2 misfire that’s intermittent and upon looking at the coil pack I noticed that one of my injectors is discolored. Could this be a bad injector and potentially causing the misfire? Misfire only happens intermittently on start up and goes away if I turn off and back on again. Pic below- ID1050x injectors

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[93xsg]

Hmmmm I mean that just looks like an anodized metal cap. Without testing the injector in some way, I don't think anyone from a picture can accurately determine if that's from corrosion, heat, electrical issues, bad injector etc. Maybe I'm wrong....
Seems a little suss that its a cylinder 2 misfire and that looks like the number 2 injector??? Hmm


With intermittent issues, I typically try to think of what is different or what triggers the event. Often times that will point you in the right direction. Could be as simple as a loose/corroded connection.


There's some easy redneck ways to test injectors as working. You could disconnect ignition (aka spark, you don't want to blow up or catch your car on fire). Rig the injectors up on the fuel rail, and crank it and watch the spray. If they all look they same, its probably good to go.



There is something to say about noticing something off and investigating into it...follow that intuition and at least knock that off the list of possibilities. (On my dirtbike I fixed recently, I noticed an empty plastic block off plug fell out of the back of the ECU connector, leading me to suspect wear and tear on the ECU harness, and the culprit was a bad power feed in the harness to the ECU)

Really diagnosis is starting with the basics, and eliminating everything through testing, until you are left with the only solution. Sometimes its not fun and seems useless. But eventually you can figure it out.

Honestly....every time I've had to fix my DSM. The checklist to post for a tune has always solved it. See the post below. And go through all of those tests. If it still ain't fixed, I bet your car runs better! Boost leaks, throttle body adjustments are major. It's also good to ensure motor health, leak down and compression. I know yours is a misfire, but that means it could be spark, air, fuel, timing or compression causing to not fire properly. Not a bad place to start. (the big 5, spark, air, fuel, timing, compression aka what a motor needs to run)

ECMlink - Want help from ECMlink experts? Read this or receive no replies from the Wisemen

In order for us to help with your tuning issues, certain assumptions about the mechanical state of your car have to be made on our end, since we can't see the car in person. Because of this, it is very important that you do everything possible to ensure that we are looking at what we think we...

www.dsmtuners.com

KISS = Keep It Simple Stupid. A lot of times problems are a lot simpler than we think! Never overlook the simple stuff or rule something out you think you've already checked before.

Good luck

edit thoughts....you could also look up an ohms resistance test for those injectors. If one of them is no good electrically it may show up this way with minimal effort.
Also, don't be sad when tests performed don't give a solution, its one more thing it isn't and one step closer to the solution

 

[luv2rallye]

Or swap #2 injector with a different cylinder one and see effect.

 

[OldGregg]

Biggest clue is you just touched something. Go back over your work. Make sure wires are seated well on both ends, Check coil towers for cracks etc. Check your new wires for arc spots. Just because they're new doesn't mean anything. It's a different part than what you had.

Thank you Pauleyman. I checked all spark plugs, swapped plugs, checked wires, replaced ignition coil. Still Cyl 2 misfire... I guess the next step would be injectors? Also, out of curiosity, could fuel or MAF adjustments in EcmLink fix this problem? I'm trying to make changes in EcmLink to smooth everything out but can't get there now that the misfire is constant. I'm running a 2.3L stroker with ID1050x injectors on E85 and 16G. My mechanic said he did a compression test before he sold me the car and said they were all at 200. Any ideas would be greatly appreciated. I've read through all of the other threads and understand there could be a sleuth of different things causing misfire- CAS/Wiring Harness/ECU/o2/etc..but would like to work my way up to having to bring it into the shop.

 

[OldGregg]

Hmmmm I mean that just looks like an anodized metal cap. Without testing the injector in some way, I don't think anyone from a picture can accurately determine if that's from corrosion, heat, electrical issues, bad injector etc. Maybe I'm wrong....
Seems a little suss that its a cylinder 2 misfire and that looks like the number 2 injector??? Hmm


With intermittent issues, I typically try to think of what is different or what triggers the event. Often times that will point you in the right direction. Could be as simple as a loose/corroded connection.


There's some easy redneck ways to test injectors as working. You could disconnect ignition (aka spark, you don't want to blow up or catch your car on fire). Rig the injectors up on the fuel rail, and crank it and watch the spray. If they all look they same, its probably good to go.



There is something to say about noticing something off and investigating into it...follow that intuition and at least knock that off the list of possibilities. (On my dirtbike I fixed recently, I noticed an empty plastic block off plug fell out of the back of the ECU connector, leading me to suspect wear and tear on the ECU harness, and the culprit was a bad power feed in the harness to the ECU)

Really diagnosis is starting with the basics, and eliminating everything through testing, until you are left with the only solution. Sometimes its not fun and seems useless. But eventually you can figure it out.

Honestly....every time I've had to fix my DSM. The checklist to post for a tune has always solved it. See the post below. And go through all of those tests. If it still ain't fixed, I bet your car runs better! Boost leaks, throttle body adjustments are major. It's also good to ensure motor health, leak down and compression. I know yours is a misfire, but that means it could be spark, air, fuel, timing or compression causing to not fire properly. Not a bad place to start. (the big 5, spark, air, fuel, timing, compression aka what a motor needs to run)

ECMlink - Want help from ECMlink experts? Read this or receive no replies from the Wisemen

In order for us to help with your tuning issues, certain assumptions about the mechanical state of your car have to be made on our end, since we can't see the car in person. Because of this, it is very important that you do everything possible to ensure that we are looking at what we think we...

www.dsmtuners.com

KISS = Keep It Simple Stupid. A lot of times problems are a lot simpler than we think! Never overlook the simple stuff or rule something out you think you've already checked before.

Good luck

edit thoughts....you could also look up an ohms resistance test for those injectors. If one of them is no good electrically it may show up this way with minimal effort.
Also, don't be sad when tests performed don't give a solution, its one more thing it isn't and one step closer to the solution

Thank you for your guidance. I'm definitely trying to keep it simple and work my way back to having to get it into the shop.

I checked all spark plugs, swapped plugs, checked wires, replaced ignition coil. Still Cyl 2 misfire. Time to test the injectors! Out of curiosity, could fuel, MAF or timing adjustments in ECMLink fix this problem? I'm trying to make changes in ECMLink to smooth everything out but can't get there now that the misfire is constant. I'm running a 2.3L stroker with ID1050x injectors on E85 and 16G. My mechanic said he did a compression test before he sold me the car and said they were all at 200.

Any ideas would be greatly appreciated. I've read through all of the other threads and understand there could be a sleuth of different things causing misfire- CAS/Wiring Harness/ECU/o2/etc., but just trying to figure this out myself.

 

[pauleyman]

Id still swap as much as I can to see if it stays on number 2. You could swap two spark plug wires and see if the problem moves. Same for injectors. Swap two. No you cannot tune this out if its isolated to one cylinder how could it be tune? Adjustments affect all cylinders. Leakdown on number 2 would be a good idea.

 

[OldGregg]

So update here, I didn’t have my injector size and global fuel set correctly. Got that and CAS set correctly, cleared code (P0302) and drove around for a few minutes ran fine. After engine was warmed up at idle, the car switched from closed loop to open loop and threw a P0304 Cyl 4 misfire! I suspect maybe the afr isn’t set correctly in the narrowband simulation? Any ideas would be greatly appreciated.