Tach and PC3 readings do not match

[BusaCorona]

See! What had happened was,.....

I was putting a new map on my PC3 the other day and I noticed that my Tach on the bike was around 1100-1200rpm and my PC3 software was reading and fluctuating from 1256 - 1430rpm up and down. It is a 99, I had just finished syncing the TB's. I have done the small air box mod and have removed the PAIR system.

What could cause the two to read differently? And, is there a fix to the fluctuating rpm?

I am taking her to get dynoed and tuned next week and hope to have most of this fixed before then.

Thanks in Advance for any and all assistance!!!

 

[GPW]

set your TPS when the bike is warm...sounds like the TPS inputs are off

 

[dadofthree]

 

[turbobusa2000]

set your TPS when the bike is warm...sounds like the TPS inputs are off

That would explain the fluctuations in rpm but not why the bike and the pc are reading different rpms.

 

[BlueHaya]

maybe your gauge reads bad.

I worked on a friends drag bike that was previously wrecked and the gauge is around 500-600 rpm's higher.

What does the PCIII read from?

 

[Professor]

The tach is off. I've seen it on mine (and a few others). My PCIII, data logger, and shift light all match. The factory tach is the odd man out.
They also matched the Dyno tach.

BlueHaya, the PCIII reads the crank trigger. My data logger uses the injector pulse, and my shift connects to the tach output of the ECU.

 

[BusaCorona]

Thank you all for your input, I have researched setting the TPS and will get on it this weekend!!!

 

[01LANDROCKET]

Mine was off also but I have aftermarket gauges so I just blamed it on that.

 

[tex_garza]

 

[BusaCorona]

Thanks again all, got on it this weekend. Set the TPS (what a PITA job)!, and all is well!! The bike is going up tonight for Dyno Tuning at Evan Steel Performance in Tucson, cant wait to see the results!!

 

[suzuka1980]

yes, TPS problem

 

[davrai]