Isolating the Throttle Bodies from Each Other to Defeat Port Robbing

Good information. Look forward to your progress .

pingu-nz said:

Just spoke with Steve at powerhouse,
The power commander can be setup for dual map which will fuel each injector separately ,
He also suggested leaving the iac balance hose in place as there is no adjustment for the vacuum for each throttle body , but did say it will make little difference when the throttle is wide open.
This is a recommendation for the setup on my bike with the PC fitted and iac blocked .
Tony
I have left the iac plugged in and installed at this stage . But will look to remove and plug at the t piece in the future .

Cheers
Paul

Click to expand...

If you don't have a problem it's probably best to just leave things as they are. This whole charge stealing saga only kicked off as I was trying to sort the idle out - it's not mission critical. I'd still like to see results from other bikes in case it's just an issue with mine i.e. I've stuffed something up!

But it only seems to be a problem at idle - although I'll be taking a look under load when it goes back on the dyno.

At this point I'm not really sure what was causing the problems with idle. I suspected that the IAC valve was faulty, but couldn't sort out a good way to test it without modifying the wiring harness, which I was reluctant to do. Similarly, when I removed the narrowband O2 sensors, I suspected part of the problem was that one of the sensors was bad. Now I'm not so sure of that. The poor values that the ECU reported for AFR could also be explained by the port robbing theory. The one thing I am sure of at this point is that the bike now idles properly, and the difference is very noticeable. In hindsight, it probably would have been better to plug the IACV hose first, and see if that improved the idle performance, and then block the connecting passage to see if there was more improvement. In future, I hope to fit wideband O2 sensors with the newer Delta 400 ECU, which has the ability to use them for closed loop control and auto-mapping. But for the moment, I'm happy to enjoy riding the bike as is, and experimenting with some fuel and ignition map changes.

Ken