Challenging to Diagnose Misfire on a 2012 Dodge Charger 8-Cylinder

Bernie heads out to diagnose a 2012 Dodge Charger with a misfire. The misfire is said to be worse at idle and clears up off idle or when driving.

After more than a year of trying to fix this Dodge Charger, it has been labeled unfixable. The vehicle has had almost every part replaced to remedy this misfire and it is still present. New lifters, camshafts, rings, heads and coils.

In this video we see the importance of trusting and understanding the data you gather when diagnosing a vehicle. Advanced tools like the Intelligent Engine Analyzer (IEA) gives precise direction and displays what is happening inside the combustion chamber.

During his diagnosis, we first see how fuel trim shows the issue is more likely ignition, not mechanical or fuel related and both banks of the engine are affected the same.

Using scan data, fuel trim and mode 6 data, we know it’s time to hook up the scope. Bernie uses his IEA tailpipe sensor along with a scope lead connected to cylinder 1 to synchronize his data.

Using the IEA software, a cylinder 1 misfire is confirmed. As the shop described, the misfire did in fact clear up as the RPM was raised.

Moving on, the power having of an 8-channel scope is shown. Each cylinder is connected to a single channel on the eSCOPE. Stacking all the primary signals shows no turbulence in cylinder 1, compared to all other cylinder. But Why?

Fuel injector patterns looked a little different, so we perform a fuel injector flow test, which shows normal flow rates, and a new injector on cylinder 1.

Through strict analysis of cylinder and intake pressure, Bernie sees a problem with cylinder 1 when compared to other cylinders. In the end, Bernie finds the wrong lifter installed in cylinder 1.

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