Long Tube Header Dyno results & Photo

[WolfWings]

Originally Posted by ddongbap

Unless you're missing fuel injectors in two of the cly. jk=]

Not how it works. Only diesel engines and direct-injection engines have individual fuel injectors 'in' each cylinder. Most have multiple injectors to equalize the air/fuel ratio across the cylinders, but even if you have a single fuel injector fail it should cause a global drop in overall fuel available, with a minor to major additional localized drop on the closest cylinders to the fuel injector that failed. The global drop should still be picked up regardless of which exhaust runner the sensor is in.

And then there's cars that only have SPFI (one injector for the whole engine) instead of MPFI, and even among MPFI there's sequential (one spurt per cylinder timed with the intake stroke to fine-tune the air/fuel ratio beyond just flattening it across all cylinders, what all super-modern engines like our Yaris use, admitedly maximized local effect from a single failed injector), simultaneous (timed spurts from all injectors at the same time, pure air/fuel levelling across all cylinders, least impact from a failed injector), and batched/hybrid that fires injectors more often than needed (more than once per stroke), but vaguely synced with the intake cycle, usually I've seen that only on engines that also have a waste-spark ignition system or V engines to simplify the ECU logic and use a wiring harness that just Y-forks to each bank for the injectors instead of running individual control circuits for each injector.