Hi guys, have a 2014 Super Glide Custom, 96ci, it has developed a high idle problem, just happened out of the blue. Keeps throwing error code P0507, started out as intermittent problem but its now persistent, as soon as you take off, it goes to high idle, between 2,200 and 4,200. Replaced the IAC, checked throttle cable adjustment, all good the butterfly is returning all the way, replaced engine temp sensor, no change. Battery is good, 13.08v engine off, 13.6v at idle. If you clear the error code and re-start, idle is OK, until you take off again. It's not the throttle butterfly, have sprayed around the intake looking for air leaks, idle doesn't increase. It was not rideable, so the interim fix is that I cleared the error code, and while the idle speed was at just over 1k which is the lowest I could get it, I disconnected the IAC so it stays in position, just makes it a bitch and it stalls till it heats up. I've now taken it for a fair few rides, and the idle does not go up, just doesn't have that nice low lumpy idle we all love. So, its definitely something telling the IAC to open excessively, but I am running out of ideas. Harley shop is booked out for 3 weeks ... any ideas??, do you think loading a new Stage 1 Map might help??? (It has Vance and Hines Long Shots and Screaming Eagle Intake, otherwise standard)

 

Have you followed the reset procedure for the IAC? It is in the service manual but Google can find it too.

 

Thanks djl, yeah tried that, there are a few version of it, 3 times, 5 times, wait 5 seconds etc, tried them all, goes back to normal idle, until you get 5 min down the road, then progressively starts getting idling higher, that's why I thought it was temp sensor as it seemed to change with engine temp, and temp sensor was about 100 ohms out at 90 degrees C, new genuine sensor, no change

 

Leaky injector?

 

More than likely a vacuum leak.

 

OP says checked and no leak.

 

You're right!I read through it pretty quick and missed that.

 

Thanks Baird, I like your thinking, so you think maybe oxygen sensor sends signal to open IAC to compensate for being so rich?, thanks heaps i'll check that out

 

if that was the case the oxygen sensor would spike and stay there and that normally would trigger an O2 code.In most FI systems the O2 doesn't have that much influence to cause the idle to jump that muchA leaky injector would make it hard starting after shutting it down hot.The fuel pressure would all dump into the cylinder with the leaky injector and run rough until it cleaned the excess fuel out after it did start.I could be totally wrong having never worked on Harley FI but they pretty much all work the same way.JMHO after wrenching for a living for a long time.Any chance the ECM could've gotten a voltage spike like from jump starting it.A bad ECM ground or even a weak battery can cause lots of strange ****.

 

Thanks will check the ECM ground, it has been jump started, but the issue started a week after that. The guy I bought it off trailered it to my place, and the alarm was going off in the trailer the whole way and flattened the battery. I jump started it once with protected leads, then ran it around the block and has been good ever since. 13.08V engine off, 13.6 at idle. I also use a trickle charger but not always. The only thing that was different was that the issue started after the first time I filled it with fuel, I thought maybe a bad batch but i've gone through 2 tanks since and no change