A Suzuki GSX1400 fitted with an ignition advancer to the crankshaft, which gives 4° advance. Now in the old days of carb-fed engines banging on an ignition advancer would instantly make the bike feel crisper and sharper. The owner fitted an advancer and a Power Commander to his bike in the hope of the same effect, and as the GSX14 is a fairly conservative bike in a modest state of tune there will be some benefits, but the problem is with the engine’s ECU – because the pick-up point is in a different place its cables are corrupted.
The 4° advance means that it is in effect 4° on from where the ECU thinks the pick-up should be, throwing out the TPS (Throttle Position Sensor) and causing a snatchiness to the power delivery at the bottom end. To compensate for this we’ve adjusted the TPS sensor to compensate for the change and added fuel, because the ECU thinks it’s in a different place on the fuel table than it actually is. This is an example of the unforeseen knock-on effects that can happen when modifying a fuel injected bike.