Quote:
Originally Posted by Red ones
On that basis, why the jerkiness we all remove by adjusting the TPS? Is the mapping just carp?
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The SV uses an engine load sensing scheme called Alpha-N (alpha=throttle angle, N=engine RPM) to estimate how much air the engine is consuming, so it can work out how much fuel to inject. This means the throttle position sensor is a primary sensor for the fuel injection, it has no other way to determine the engines air demand.
At low RPM, a tiny throttle opening causes a big change in airflow (e.g. a few degrees opening could easily double or triple the airflow and fuel demand). The ECU has to be able to accurately detect a very small change in the throttle angle to be able to deliver the correct amount of fuel, so it should be obvious that even a tiny error in the TPS calibration can really mess things up at low RPM. This is what causes the jerkiness and why setting up the TPS properly fixes it.