BP EGT Temp question

[Dean Dorsey]

I got one I can't figure out, on my modified 2.4 BP. I have a converted digital 2.4 BP makes roughly 280 hp. exhaust is opened to 260 specs digital A-40 Rapair box, chip and steamwheel. When I last ran this motor in the heat of summer last season at 90+ degrees to make 1,100 degrees I was at about 96 percent on the steamwheel the box itself is not adjustable. Now in the cool spring about 58 degrees I have to turn the steamwheel down to about 75 percent to accomplish 1,100 degrees the power still seems to be there. Water temps are alot cooler and head temps are also cooler at running speeds. Logic says that if air temps are cooler a 2-stroke will run leaner rather than richer, my 260 motors run this way and are extremely lean right now. The only change since I ran it last was I converted from the BP tuner to an oval 260 tuner to match the exhaust chest and to breath better, this I also expected would lean me out more, but result is just the opposite, could a MAP sensor be to blame or something else rpms are even about 100 higher than I ran in summer , bottom end is also much richer. I thought my box itself my be overcompensating for the cooler temps, but if so why is this not happening on my 260 with either my Rapair A-48 or my PCU, both are running really lean and have to be watched carefully upon deceleration . Any ideas are appreciated. Thanks, Dean

[us1]

Hi Dean the temp sensors in the ECU and the motor should be adjusting the mixture for the different air temp changes. Sometimes this does not happed accurately. It’s just the way the ECU is processing the info. I have had the same problem with certain ECUs and not with others. Just use your steam wheel to make the compensation. What was you electrical problem?????????????