




At some point during my trip back to Omaha a few weeks ago, My Guzzi Breva started to run not quite as smoothly as usual. The low speed throttle transitions were choppier than usual, resulting in a herky jerky low speed condition. On the way back from Omaha I stopped off at a Guzzi dealer to have them give the bike a once-over. It really did not help with the low speed jerkiness and the idle speed actually increased quite a bit, about 300-400 rpm above factory specification.
After having read a lot on the web about the sophistication of the new fuel injection systems in these newer bikes, I decided to purchase a piece of software and a cable called Technoresearch. This software and the specialized cable allows one to hook directly to the ECU (computer) which controls many things on the bike. The Technoresearch software and cable arrived in a keen looking black case. Neat! I opened it to find a cd rom and the rather elaborate looking cable.
So I was pretty darned excited to try to hook it up and see what was going on with my bike this morning. Once I got the bike's computer talking to my laptop, I could run all sorts of diagnostic tests on various parts of the bike, like the fuel injectors, gauges, fuel pump, etc. It also allows me to check to make sure certain values are set to factory specification. Well, one value was outside of factory spec by a fairly significant margin. This value is called the Throttle Position Sensor (TPS) voltage.
Now for a little lesson courtesy of Wikipedia.com:
A TPS is a sensor used to monitor the position of the throttle in an engine. The sensor signal is used by the ECU as an input to its control system. The ignition timing and fuel injection timing (and potentially other parameters) are altered depending upon the position of the throttle, and also depending on the rate of change of that position.
So, essentially, the TPS is pretty crucial to the proper running of a modern, fuel injected motor. Well, my TPS value was, as indicated earlier, out of spec. The new software allowed me to reset the TPS value back to factory spec with the click of a button! You can see from the screenshots how I hooked the cable to the bike and before and after screenshots showing the TPS value being changed from 3.70 to 4.60.....sweet!
The result? The low speed herky jerky behavior has nearly disappeared! So I am a happy camper right now! :=)