Maxima with a Cylinder 2 misfire

Zakk Technician Texas Posted   Latest  
Resolved
Driveability
2010 Nissan Maxima S 3.5L (VQ35DE) (RE0F09B)
P0302 — Cylinder 2 Misfire Detected
Misfire

Vehicle has a cylinder 2 misfire that's almost a dead misfire but isn't a full dead misfire. Found cylinder 2 and 4 were both misfiring. Performed a RC and all looked even. Found the plugs super worn and when I swapped the plugs around it seemed to kinda follow but it was hard to tell exactly (this vehicle doesn't have misfire counters on the scantool) and I only had cylinder 6 to swap to, Swapping coils has no change. Tried to look at secondary ignition waveforms but can't seem to get a clear waveform. Cylinder 2 and 6 (good cylinder) both look the same when looking at secondary ignition. So ended up selling plugs and cylinder 2 is still misfiring but cylinder 4 seems good now, misfire is at idle and seems to get better with higher rpm. Performed a fuel leak down test and cylinders 2,4,and 6 all leak down the same. Here are some waveform captures of cylinder 2 and 6 with in cylinder and coil control and injector voltage. When comparing cylinder 2 with 6 all looks the same to me. Does anything stand out to anyone?

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Cody Diagnostician
Illinois
Cody
   

Misfire at idle that goes away at higher engine speeds could be a valve leaking. Might want to do a leak down on cylinder 2. The fuel leak down test you stated is that checking fuel pressure and commanding 1 fuel injector on at a time? Injector flow rate in other words?

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Zakk Technician
Texas
Zakk
 

yes, it was injector flow rate test. Also I provided waveforms of in cylinder pressures which indicate good compression. I don't see anything weird with the intake valves in the waveform but I am not an expert at analyzing these waveforms.

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Ray Diagnostician
Ontario
Ray
 

A pressure transducer in the intake, while cranking will compare each cylinder's intake stroke vacuum pulls. A pressure transducer in the exhaust, while cranking, will compare each cylinder's exhaust stroke pressure pulses.

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Rusty Owner/Technician
Massachusetts
Rusty
 

I agree with Cody. Idle misfires are almost always indicative of compression loss (valve leakage), camshaft or valve spring problems, or a vacuum leak close to the intake port for that cylinder.

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Ray Diagnostician
Ontario
Ray
 

Zakk, disable the fuel system, connect a pressure transducer in the intake and in the tailpipe, then crank the engine.

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Zakk Technician
Texas
Zakk
 

I will do these tests a little later today. I have to finish some other cars before going back to this one. Thanks

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Zakk Technician
Texas
Zakk
 

Ray, here are the 2 waveforms. One is cranking intake pulls and the other is cranking exhaust pulls both synced with cylinder 2 ignition coil firing signal. I am confused on the exhaust waveform because there are more then 6 pulls between the firing events?? I only have one pulse sensor so that's why they are 2 separate waveforms. Thanks

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Dmitriy Analyst
Ontario
Dmitriy
 

Well, that's a lot more pulls than usual, but 2 and 6 look similar… diag​.​net/file/f5rmq1c48… ​

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Ray Diagnostician
Ontario
Ray
 

In the cranking intake pulls, cylinder 2 has two weak intake stroke vacuum pulls.

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Helpful
Rod Diagnostician
California
Rod
 

What are your ltft+stft at idle and at 2000 rpms ?

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Zakk Technician
Texas
Zakk
 

So I did notice that STFT on bank 2 is more lean at idle then bank 1. Idle Bank 2 = STFT 10 LTFT 0. Idle Bank 1 = STFT 4 LTFT 0 (battery was disconnected before gathering these readings). Above idle they seem normal. (between -3 and 3)

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Rod Diagnostician
California
Rod
 

Can not tell you what is wrong , but I can tell you what I would concentrate on , vacuum leak, injector flow pattern possible carbon on intake vale.

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Zakk Technician
Texas
Zakk
 

I performed an injector flow test and the front 3 cylinders all leaked down the same PSI. I haven't performed a smoke test on the intake but fuel trims aren't to bad other then the positive 10 on bank 2 but it fluctuates up and down and 10 is the worst. Wouldn't that be from the misfiring cylinder? Also I did a BG induction service with no change in the misfire after words. I put a camera down…

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Jesse Engineer
Missouri
Jesse
 

First I'd do is a compression test on 2,4,6. Then a leak down test if the compression test is over 150 psi per cylinder. If there's any problems, it won't be. I would put 3 new plugs in the 3 cylinders if it passes compression test. Check plugs for carbon tracking down the side of the plug to the base. Even though you swap coil packs or plugs, carbon tracking will stay with both and make…

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Zakk Technician
Texas
Zakk
 

Cylinders 2,4,6 are all about 180 psi compression. All plugs are new and the back bank got new coils and I swapped those back coils onto the front. Have not done cylinder leak down yet. I will later today.

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Paul Mechanic
Illinois
Paul
 

I believe Ray has shown you your cylinder 2 deviation indicating mechanical (if that is your sample he is depicting- my phone won't open waveform). Does not mean cylinder 2 is issue, however, unless exhaust valve is leaking, some other cylinders intake may not be fully sealing for a number of reasons. If Ray's image is not your capture- disregard as to your particular issue. Dimitriys image…

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Ray Diagnostician
Ontario
Ray
 

Paul, the GIF file that I posted is from Zakk's PSD file.

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Dmitriy Analyst
Ontario
Dmitriy
 

There is more to that: the deviation for the intake waveform only happens around second 2, and disappears afterwards. Even if it is real (and not a result of something like low oil pressure at the start of the crank), could this produce an almost dead misfire? diag​.​net/file/f54w1voq8… ​

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Ray Diagnostician
Ontario
Ray
 

Dmitriy, yes, the intermittent deviation in the vacuum pulses can cause the misfires at idle and I will try to find my captures from a Dodge 3.6.

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Ray Diagnostician
Ontario
Ray
 

Zakk, with the fuel system disabled, can you do a long cranking capture with your transducer in cylinder 2. All of the compression peaks should all measure the same compression.

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Zakk Technician
Texas
Zakk
 

Sorry for the late responses, my manager wanted me to finish some other cars before continuing on this one. I attached the longer cranking you asked for Ray, but this vehicle has a push to start and it only cranks for a short period of time before stopping itself so I did 2 cranks. Also I added a waveform of cylinder 2 running with a snap. Then added a pic of a close up on the decel on the snap…

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Ray Diagnostician
Ontario
Ray
   

Zakk, I can't open the files so I'll download a newer version of the pico software. I just called Autonerdz and I already have the latest and the best version of the pico 6 software.

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Zakk Technician
Texas
Zakk
 

Yeah, I am using picoscope 7. I am able to download and open the files on my end. I don't have time today to recapture everything on picoscope 6. You can download picoscope 7 for free and then I'm sure you'll be able to open them. Sorry

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Ray Diagnostician
Ontario
Ray
 

You should repeat the same tests that you did with another cylinder for comparison.

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Glenn Owner/Technician
Texas
Glenn
 

Hi Zakk, Not sure if anyone mentioned this, but did you try a plain old fashioned vacuum gauge? A needle bounce in time with the mis would narrow this down, usually. I don't have PICO 7; I am running a 32-BIT system w/ PICO 6. PICO 7 requires 64-BIT. A camera shot might be good for those of us who are not on the cutting edge of technology currently. (I'm not prepared to buy another new…

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Geoff Diagnostician
Hawaii
Geoff
 

"this vehicle doesn't have misfire counters on the scantool" Nissan expects you to use the Power Balance function, to kill injectors one at a time. Monitor live data for the rear O2 sensors (warmed up!) while you do it. When you kill an injector, and the engine does NOT get rougher, that is the dead cylinder. If the injector is working properly, when killed, that bank O2 will drop to 0 mV. I'm…

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Zakk Technician
Texas
Zakk Resolution
 

Ended up finding the ignition coil wiring was rubbed against the head in a weird location and would only short when the coil was inserted into it's original location. Once I pulled the coil up and out it would come back to life and start sparking. That's why every time I would check spark it would be fine until I reinserted the coil. I don't know why it wasn't setting any other code with the…

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Dmitriy Analyst
Ontario
Dmitriy
 

Good job, Zakk!

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Ray Diagnostician
Ontario
Ray
 

Some COP secondary Wands don't work well on some COPs. 2 wire distributor inductive pickup coils work well to get good signals on any COP. In the animated GIF, the top trace is 3 Honda distributor pick up coils on 3 COPs. I'm accelerating into a 1500 rpm brake torque and the CH B shows the secondary spark burn voltage rising because the injector is disconnected. I'm using an injector voltage…

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