free website stats program loss of idle speed control | Page 2 | Harley Davidson Forums

loss of idle speed control

Is the PC currently installed and wired in. What was the DTC code you pull from the error log? Was it the only code you had. When the rear wheel stop turning, does the the engine idle down to the CORRECT idle speed. Not just idle down but idle down to the CORRECT idle speed.
 
Yes, the PC is on.

The code is "loss of engine idle speed"

When the wheels stop the engine returns to normal idle speed. Mechanic also discovered when engine is killed at highway speed and restarted it idles at normal rpm.
 
jsnewk said:
When the wheels stop the engine returns to normal idle speed. Mechanic also discovered when engine is killed at highway speed and restarted it idles at normal rpm.
Click to expand...

Until you get a handle on what is going on, you need to unplug the PC. You must unplug it just for the duration of this problem. With the PC wired in, it now becomes an interface between the ECM and all I/O devices. The ECM is no longer in DIRECT control.
This is the way I would diagnose/repair this problem.

In entry point #3 when you said the "Mechanic replaced trans sensor and wheel sensors". When you say "wheel sensors" you mean the bearing sensors as in ABS? You have ABS?

There is a target idle value stored in the ECM. There also MAY be a target value stored for idle in the PC. The IAC stepper has two extreme limit stepper counts. A max Low count and a max high count. A P0505 means the ecm has pegged the instructed IAC stepper count and the RPM of the engine still can not be matched to the target RPM value.

One more time. Is this the ONLY stored code you have in the error log.
 
jsnewk said:
The problem is not the Power Commander as it does it with or without it installed.
Click to expand...

Based on what you said in entry point #3, you may actually have two problems. I think you already know what my next move would be. Unhook the PC & clear the P0505 error code. Yes, you still may have an idle issue but you need to see if you post another P0505 DTC quickly.

If you quickly post another P0505 DTC, your down to just a couple of things it can be. If you don't post another P0505, you once again are down to just a couple of things it can be. (different but few)

Since you are not the one actually fixing the bike, your in a bad position because relaying info from a web site to your mechanic does not usually go over very well.
 
Was 2007 still a cable pull throttle and not throttle by wire.

You never explained the events that take place during an abnormal high idle event. Lets start with a stone cold bike. Standing still, when started, does the bike have a stepped up idle during warm up like it should. As long as you standing still, does the engine idle settle down on it's own while warming up like it should. It should come off "choke" on it's own and idle down to normal.
Does it.

Now lets fast-forward to a engine that is fully warmed up. You start the bike and the engine speed is at a normal idle. As long as the rear wheel is NOT turning, you can twist the grip (race engine) and the engine returns to a normal RPM. But once you set out moving, the lowest RPM NOW becomes 2800. Once the engine goes above 2800, the rpm never comes below that point until the rear wheel stops turning.
Does it.

Entry point #8-2nd sentence implies that your having this bike serviced by a dealership. If it is at a dealership, their Digital Tech (or even a SEST will work even better) tells you what step number the ECM believes the IAC is at during any running RPM. When the RPM is at 2800, what step number does the ECM think the IAC is at?
It is easy to view the screen and seen what the step count is vs the RPM on the tach. Or using play back mode with a SEST VCI it is even easier.

If your no longer at a dealership, your Indy will at least need a SEST, VCI, or a HD-41199 LED IAC tester to see what is going on.

As the "step count" goes to Zero, the pintle of the IAC is fully extended thereby cutting off the throttle body air bypass and lowering the RPM. If the step count does not match the RPM range of the tach, then you have a bad IAC. You really need to see what happens to the step count when the wheel stops turning. (This can very easily be done with a SEST (VCI) in record mode)

**The important thing to realize is the IAC does not send any position information to the ECM. The ECM sends out enough steps to perform an IAC "reset". It now uses that position as a reference point. This explains why a key re-cycle (entry point #12 last sentence) temporarily clears up the problem.**

I am not there in person but based on what you have said, I have this feeling the PC is still hooked up at this time. If that is true, in my opinion your making a big mistake by doing that.
 
I am sending your reply to the Mechanic. It is not at the dealer now but he has enlisted the mechanics there for help. Thank you again. I will pass on what they find.
 
You must log in or register to reply here.
Back
Top