Fuel Injectors: Larger Size & Timing Adjustment

Hello everyone,

"About 15,000 km ago, I replaced the injectors in my 1Z engine with 205 injectors (AFN) – without taking any other measures. Since then, the car has generally run great, although it occasionally smokes a bit."

On Monday, the engine will receive a new timing belt from the authorized dealer. Should I advise the mechanic to consider using larger injectors and to adjust the injection timing in a specific direction?

Edit:
"without taking any further action" wasn't quite right: The AGR (air control valve) is sealed, and I also cleaned the mass airflow sensor, which means it's no longer positioned exactly where it was before - although I'm not sure if that's relevant to the question/answer."

Hello Tino,

Since the opening pressure should be the same for all injectors, nothing else needs to be considered during the replacement of the injectors or when setting/testing the initial spray pattern.

Best regards, Rainer.

Okay, thank you!

I thought that because the injected amount might pass through the nozzle faster, the injection end would be before the normal end, and therefore the start of the injection might have been delayed slightly to still reach the optimal "center." However, I suspect that the tolerance range is so large that the deviation doesn't matter .

Once all my repair work is completed, I will definitely reach out to you again - a corresponding software adjustment (chip tuning) could certainly be beneficial in that case .

Hi Tino.

You've made a small mistake in your thinking. The injection duration doesn't change because the EDC system doesn't know anything about larger injectors. It simply injects more fuel within the same injection time.