| Author | Message | ||
     Dave_02_1200 |
Fuel Injection Gurus: I have a question. Based on my limited understanding of the way the DDFI works, it seems to me that one could achieve a richer mixture throughout the RPM range by simply altering the oxygen sensor signal to the ECU. If I am correct about that, it could avoid the complexities of changing ECUs and, because the stock ECU would provide a richer-than-stock mixture in response to an apparent voltage that would be somewhat lower than the actual O2 condition would normally indicate, nothing else would have to change. If I could find an appropriate way to introduce some resistance of a known value to reduce the O2 sensor voltage signal to the ECU by, say .100 volts, it seems to me that the ECU would enrich the mixture to an amount that would otherwise send a signal of .580 volts to the ECU but the ECU would "think" it was delivering the right mixture based on the apparent .480 volt signal. This approach would be different than the one used by Power Commander etc. that alter the ECU signal to the injectors. That might work fine on other "open loop" systems but I don't see how that would work properly on an "open loop" system. It seems that, with a closed-loop system like our Buells have, the Power Commander approach would alter the signal to the injectors and temporarily enrichen the mixture only to have the ECU read the over-rich O2 signal and correct the richness back to a stock mixture. (Back to square 1.) The approach I am attempting to describe would, in theory, avoid that problem in a closed-loop system because the ECU would be delivering a mixture that "looks right" to the stock map. I know it might seem like I have had too much coffee today but my S3T is my first DDFI bike and I am just trying to get to know it better. Any thoughts would be appreciated. Dave | ||
| Pikeslayer |
I like the way you think. Sorry I can't offer any advice, but it sounds like it is worth a try. That would be awesome. A little dial mounted in the dash so you could adjust on the fly! | ||
| Natexlh1000 |
Sounds logical. You would need to use a voltage divider though not just a straight series resistance. I had thought of doing similar things with mine but found the root of my problems to be in a poorly mounted muffler that was intermittently interrupting the groundpath of the sensor. What wrong things is your bike doing? | ||
| Dave_02_1200 |
My bike is running great. It has a Buell race kit with ECM, pipe, etc. That bike is fine "as is". My interest is based on curiosity and a desire to be able to have greater mixture control like I do with my other bikes that have carburetors. Who knows, It might be fun if something so simple would actually work like a jet kit. | ||
| Natexlh1000 |
In theory, it adjust the mixture offset when it is running in closed loop. It then extrapolates out the rest of the curve. The "race" brain is non-EPA and allows for more flexibility in the mixture. | ||
| Davefl |
Check out the ECMSPY thread in the Knowledge Vault. You can have full control of the mixture control. | ||
| Oldog |
the PC1 & PC2 were input foolers PC3 adjusted injector pulse width the ecm also uses map values at various points on the curve |
