Ok, 2008 FLHTCU. P0502, P1510, P2127, P2138. I know what the codes are, I cleared them and im hoping the 0502 doesn't come back. As far as the other 3 I've pulled and cleaned and greased every associated connection and it still comes back.

It will idle all day long and never throw those 3 but as soon as I get on the bike they show up. Which brings me to my question. It's a stage 1 with a Dynojet Power Commander 3. I know it's no longer supported. Can I bypass that and plug straight back into the ECM to see if the power commander is taking a crap?

 

Just remove the power commander and plug the ECM in directly and see what happens. It would help if you told us what the codes mean, as I’m not going to look them up.

 

Sorry, the 0502 is vehicle speed sensor, 1510 is limited performance mode and 2127 and 2138 have to do with the twist grip sensor. Im just worried if i bypass the tuner I'm going to do some damage bye trying to run it without it.

 

Yes... you can disconnect the Power Commander on a Stage I, to see if the Power Commander is the issue...

I don't know what you mean by "Can I bypass that and plug straight back into the ECM to see if the power commander is taking a crap?"....

I believe the Power Commander is a piggy back tuner.... meaning it stays plugged into the diagnostic port to work... So just unplug the Power Commander and see if the problem goes away... The ECM will run as designed with the OEM tune, without the Power Commander plugged into the diagnostic port..

Many go Stage I without ever changing the tune, expecting the ECM to handle the increase of airflow.

I don't agree with that philosophy... but... I absolutely believe that at a Stage I, you can ride the bike without damage for the short term, if you unplug the Power Commander.

 

Pull the OEM connector out of the power commander, pull the Power Commander connector out of the OEM computer, plug the OEM harness into the OEM computer.

Clear the codes, ride and see if they come back.

If they do come on back and we will start tracing wires, looking for damaged wires, checking for values on sensors, etc



IF it goes into the diagnostic plug just unplug the P.O.S.

I hate those things, they are garbage

 

Thanks for that info...

Having never used one or worked on one, I didn't realize the Power Commander plugs in between the ECM and it's OEM connector..... I just looked it up and watched a video about their installation on a Harley.

Now I know....

And I have to agree with you, I've never been a fan of any of the piggyback tuners.....

 

Thanks for the info. I'm kind of hoping it is the issue so I can get rid of it. It takes up a lot of space underneath the seat not to mention the ton of extra wiring.

I have duals on it and i thought it originally came with O2 sensors. Hence my worry. Air cleaner and plugs are Screaming Eagle so I assumed it was Stage 1.

 

probably one of more broken or partially broken wires at the throttle body connector. codes sounds like it went into limp mode.

 

Well, I pulled the power commander and with the exception of the speed sensor the codes came back.

3 observations though, I think the bike actually runs better with it off. Yesterday it was idling about 700 rpm, now it's back up to 950 to 1k rpm when it's been warmed up. My voltage gauge has always read 15 volts when running and now it's down to a believable 13 at idle and 14 when on the road.

So I think it's going to stay off for good. Now, to get to chasing wiring.

 

Not being familiar with the Power Commanders, I looked up the install instructions....

The Power Commanders change your tune Map to an all Open loop map, no need for O2 sensor feedback.... The O2 sensors are not used with a Power Commander...

If you remove the Power Commander for more than a test... I would suggest reinstalling your O2 sensors... you may or may not have caps on the wiring harness O2 sensor connectors... The PowerCommander Install instructions I found online (different year) says the kits include "O2 Optimizers" that plug into the wire harness in place of the O2 sensors.

The default OEM tune has a portion of the map that is closed loop, needing the O2 sensor feedback.... Without the Power Commander, you'll be back to the OEM tune.

I am not sure of the issues with running an OEM tune without the O2 sensors.... but at the least I would assume that would trip an O2 sensor code, and could negatively affect performance and fuel mileage...

IMHO..... I wouldn't run the bike with the OEM tune, without reinstalling the O2 sensors, for more than a short test run to see if the Power Commander was causing the issues...