Per-Cylinder Misfire Counts and Fuel Trims on Infiniti and Nissan with ELM327
Canfiti shows a misfire counter for every cylinder, fuel trims for each bank, and fuel pressure. Here’s how to read those numbers and when it’s time to look at a plug or a coil.
Misfires are the first warning about spark plugs, coils, injectors, or compression. While a cylinder only stumbles now and then, you barely feel it, and without data you’re left guessing which of eight is to blame. Since version 0.5.4, Canfiti shows misfires for every cylinder separately, and current versions add fuel trims for each bank and fuel pressure.
The app doesn’t read trouble codes. What it shows instead are the live counters and trims themselves, which often tell you more than a single code.
Where it works
The misfire screen is verified on an Infiniti QX56 Z62 with the VK56 V8, the same engine as the QX80 Z62. An Infiniti FX (S51) owner used it to find a burnt coil.
Canfiti reads engine data over standard OBD-II, not Nissan’s proprietary diagnostics. That means the screen may also work on other cars with a CAN bus: connect and see.
On some engines the data doesn’t display correctly yet. One QX70 owner saw eight cylinders instead of six and no misfires at all.
Opening the screens
Plug the adapter into the OBD2 port, start the engine, and connect in Canfiti. On the main screen, tap “Engine”. You’ll see three cards: “Misfires”, “Fuel trim”, and “Fuel pressure”. Below them are engine oil temperature (if the engine computer reports it) and the VIN.
Misfires
Current cycle vs. 10-cycle average
The screen has two cards: “Misfires (current cycle)” and “Misfires (average over 10 cycles)”. Each cylinder gets its own row: “Cylinder 1”, “Cylinder 2”, and so on. The app works out the cylinder count from the engine computer’s response; the VK56 has eight.
The first card shows what’s happening right now. The second catches intermittent misfires that happen every few minutes and are easy to miss in the current cycle. A cylinder that stands out in both is your prime suspect.
Read the numbers, not the bar length
Each bar is scaled to the highest value on the card. The cylinder with the most misfires always gets a full bar, even if it has just one. So go by the number to the right of the bar.
Cylinder diagram
For V6 and V8 engines, the app shows an engine diagram under the counters and picks the right one automatically. On the VK56 diagram, row A is Bank 2 with cylinders 2, 4, 6, 8, and row B is Bank 1 with cylinders 1, 3, 5, 7. The arrow points to the front of the engine. A V6 gets its own diagram and labels, so go by the legend under the picture.
There’s no diagram for 4-cylinder engines: layouts vary, and the author couldn’t find a reliable one in the official service manual.
How many is too many
A few stray misfires don’t mean a repair. In the author’s experience, 4–5 misfires per hour of driving are nothing to worry about. The warning sign is one cylinder pulling away from the others and climbing in both counters.
A real example: on an Infiniti FX, the app showed 33,870 misfires on cylinder 1 in the current cycle and 4,433 on average, with the other cylinders nearly clean. The owner had just come back from a long road trip. The cause was confirmed: the coil on cylinder 1 had burned out.
Fuel trim
The “Fuel trim” card shows how much the engine computer is correcting the amount of fuel right now. Each bank (“Bank 1”, “Bank 2”) has two bars, “Short term” and “Long term”, plus a “Total” on the right. Short term reacts instantly and jumps around; long term is what the computer has learned over time. The total is the overall correction.
Normal is ±10 %, and the card says so in its subtitle. The color tells you where you stand:
| Total trim | Color | Meaning |
|---|---|---|
| −10 to +10 % | green | normal |
| 10 to 20 % either way | orange | keep an eye on it |
| over 20 % | red | problem |
The bars run from −25 to +25 %, with a green band marking the normal zone.
Positive means the computer is adding fuel because the mixture is lean: too much air or not enough fuel. Negative means it’s pulling fuel because the mixture is rich.
Compare the banks. If only one bank has drifted, look for the cause on that side of the engine. If both have drifted the same way, the cause is probably shared by the whole engine. And misfires on a single cylinder with normal trims on both banks point to that cylinder itself: plug, coil, or injector.
Reading the patterns
Misfires and trims together narrow things down. These are pointers, not a diagnosis:
| What you see | Where to look |
|---|---|
| One cylinder stands out, both banks’ trims normal | that cylinder’s plug, coil, or injector |
| Misfires on several cylinders of one bank, that bank’s trim positive | a cause shared by that bank |
| Almost no misfires, both banks well positive | something engine-wide, like fuel delivery or airflow metering; check “Fuel pressure” |
| Occasional misfires on random cylinders, a few per hour | per the author, nothing to worry about |
| Numbers never change, or more cylinders than the engine has | a reading limitation on that engine, not a failure |
Before you pull coils, double-check the diagram: on a V8 the odd cylinders sit in one bank and the even ones in the other, and it’s easy to mix them up.
Fuel pressure
The “Fuel pressure” screen shows only what the engine computer reports. The first card has four rows: “Fuel pressure (gauge)”, “Fuel rail pressure relative to intake”, “Fuel rail pressure (gauge)”, and “Fuel rail pressure (absolute)”. Rows the computer doesn’t support say “Not supported by ECU”. That’s normal and doesn’t mean anything is wrong.
The second card, “Fuel rail pressure control”, compares the pressure the computer commands with what the sensor actually reads. A deviation within ±10 % is normal, with the same green, orange, and red colors. Engine computers usually report this from around 2015 onward; older ones show “Not supported by ECU”. The third card is injection control pressure for hydraulic injectors (HEUI). On the gas QX56 and QX80 it reads “Not supported by ECU”.
Pick psi, bar, kPa, or kgf/cm² under “Options” → “Pressure unit”.
Quick routine
- Warm up the engine and drive your usual route for 15–20 minutes.
- Pull over, leave the engine running, and open “Misfires”.
- Find the cylinder that stands out in both counters and check its bank on the diagram.
- Open “Fuel trim” and compare the banks.
- If both banks are well into the positive, take a look at “Fuel pressure”.
You can check the transmission on the same drive; see the transmission diagnostics guide. Everything on the “Engine” screen is covered on the engine page.