I've been having problems with my 2003 SE Road King fouling plugs. I've got a twin scan and used it to measure AFR's and they are way to low, in the 11-12 range. The map that is loaded in the ECM has most set in the mid to upper 13's and some in the 14's so it's running super rich. But, I can't determine what in the world is causing all that. I've replaced most sensors and there are no diagnostic codes being reported. Does this mean the ECM is bad? And if it is should I replace with an aftermarket one or go back to original part and then reload my map? BTW, I also have an original SERT along with the Twin Scan so I can make changes to the ECM programing and then see the results with the twin scan. Just lost right now as to what might be causing it. TIA for any suggestions

 

It means your VE tables have never been properly calibrated. Get it to someone who knows how to use the software and has a dyno with dual sniffers.

 

It ran fine for a few years and just started this lately. It has been dyno tuned at least twice over the years and ran fine, so the VE tables should be close. Something must have changed recently.

 

How is it running now? Besides the fouled plugs are there any other symptoms? When was the last time you cleaned the air filter?

 

You could collect data with the SE unit. Check to see if IAT, engine temp and rest of the readings are normal.

 

I will do that, just haven't got to it yet. I actually haven't rode the bike since I got the SERT hooked to it (took a new cable to work with newer computers) but the readings I got with the TwinScan looked normal. But I haven't collected any data riding it yet. Air cleaner is a K&N that was recently cleaned and oiled so it should be good.

 

Cool. Take a look at your map readings, at sea level it should be close to 5 volts or 100kpa. I have found map sensors to be off showing 1000ft above sea level when the vehicle was at sea level, this caused a rich condition.
Other things that can cause a rich condition are leaky injectors, weak spark, bad plugs, restricted air flow.. I'm sure there are a few other things that I missed.

 

Thanks, I'm going to check the plug wires and I'll check the voltage, although I am about 1000' above sea level so that will be different. Any idea what it should be?

 

Try this.

 

Thanks, hopefully I get all this checked today. It's going to be too hot for me to work much outside, so I'll try to get somewhere on this.