I have a PC-V on my bike and was under the impression that the PC-V sends fake misinformation to the ECM? So in reality the PC-V fools the ECM and the ECM runs the engine with that info?

 

The PCV is downstream of the ECM and the latter doesn't even know the former is attached. The PCV intercepts and alters the data going to the coils and injectors and doesn't send anything to the ECM. In your PCV software, a "10" in one cell of the fuel-adj. tables means it is adding 10% more fuel to the amount dictated by the ECM. In the ignition-advance table it is adding or subtracting in degrees, and is also an alteration of the ECM data. Thus if the ECM is adding 7° at a given point and the PCV tables show "3" there, you will have a total of 10° of advance.

OTOH the O2-sensor eliminators, if used, do send a signal to the ECM telling it the AFR is correct and to provide no change.

 

Lots of info there but I get the picture.

Thanks.

 

how does the rev X tend work? I was under the impression that PC interupts the tach signal going to the ECM and "tricks" it (ECM) into thinking the bike is running lower RPM's than it actually is. That's why with Rev Xtend enabled the tach stops working at around 5000 RPM (or so) even though the bike revs higher. The way I understand the PC is that it both send and recieves info to/from the ECM.

 

Isn't it amazing how much wrong information is floating around the dealerships? Remember that these "technicians" as they are fond of being called are not trained by Harley Davidson. Most of them come to the dealerships after going to a school such as MMI or others. They are not Harley trained although the name Harley Davidson might have been mentioned a time or two while in class. I hate to say this because there are exceptions but most get their real world experience by trial and error, at our expense, usually at $75-$100.00 per hour for labor.

 

ditto..same here

 

The PC III and PC-V read input channels from the ECM and use a microprocessor to interpret this data and in turn drive the injectors and igntion timing. They do not use sensor or signal offset as the original PC and PC II did previous to 2003. Due to specific strategies of the 08 and newer DBW ECM and where the tach signal picks up from, when RevXtend is enabled the tach will only read to 5K as above that the PC is driving the igntion.

 

Awesome, thanks for the help.

 

Makes sense, I installed my PCV last week and have noticed it is hard to start when I wait for it to cycle through the lights. Went out and tried it without waiting and she cranked right over. Thanks for the tip gunny

 

I too have a issue with starting.. IF I wait until the eng light goes out I have to crank it alot, if I start it right away it fires up and revs for a few micro secs.. jamie has been great with questions and answers, good to see that kind of customer service in this day and age