I have a forty eight mod with V & H short shots, stage 1 SE air cleaner, dealer stage 1 download remap, and power commander V, my question is does PCV overwrites Harley’s stage 1 map ECM? I am getting different answers from Dynojet and Fuel Moto.

I am getting very low fuel mileage (between 26 – 31 MPG), Dynojet said because I am running two maps, so the fuel must be too rich, but Fuel Moto said the HD stage 1 map shouldn’t make significant changes and should not affect PCV map, should I flush the ECM to stock map and run only map from PCV.

 

It doesn't matter I had a stage 1 download before doing full exhaust and I don't have anywhere near the MPG you're getting. I get over 40mpg. Don't forget you only have a 2.1 gallon tank.

 

I've been having low MPG since day one after the stage 1 & exhaust mod, I only get 43 miles per 1.4 gallon, I suspect the dealer mapped it too rich in the beginning.

 

Yeah 43 per 1.4 gallon is really low. I usually get somewhere between 55 and 75 per 1.4 depending on how and where I am riding. I have the stage 1 v&h fuelpak short shots and SE heavy breather.

 

I had the stage 1 put on my 48 when I bought it and now have the PCV on it. The PCV will over ride all the other maps in the ecm. I did end up taking mine to a dyno shop to get it totally re-programmed and tuned and it runs way better now plus I gained 7Hp out of it. Gas mileage did go down with all my mods and tuning though.

 

This is true. The PCV will OVER-RIDE, but not over-write, the maps in the ECM. To the OP, remember that the PCV does not write anything to the ECM...all it does is take the commands from the ECM, modify them, then send them off to the Fuel and Ignition systems then takes the readings from the bikes sensors, modify some of them, and return that information to the ECM.

So both companies could be correct. IIRC the Stage 1 download from Harley doesn't do much to fueling. However, such poor gas milage usually is caused by running too rich and if you're running off a canned tune on your PCV, which is designed to run on a stock ECM and thus adds fuel, you could have an issue if the Stage 1 download DID richen the mixture since you now have the PCV richening up an already rich mixture.

I'd suggest either getting some dyno time and having their tuner adjust your PCV, reflash the ECM with the stock tune, or remove the PCV and just run on the Stage 1 ECM.

 

Why did you add the PCV to a stage 1 download? Were you having issues?

I have a 2012 48 and get 35 mpg. I also have a high flow a/c without any fuel or exhaust mods.

 

When first got my bike I had stage 1 download and exhaust installed, the MPG was low already, that's before I installed PCV, I think I'll have HD dealer reflash ECM first, if it didn't improve my MPG then I'll get a Dyno tune.

 

I love it when I see a technically correct response! If I recall correctly about the PCM, it does expect to see the stock map on a bike. I don't own one but did plenty of research prior to going SERT/dyno on my bikes.