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[highwayking]

Recently I have noticed an abnormal drop in rpms when I come to a fast stop or down shift when slowing down.  It doesn't happen all the time, but it will occur at least once during a ride.  It usually happens after I have ridden a while and if I blip the throttle, it makes the pop sound like when you are starting the engine.  By a drop in rpm, I mean it drops to somewhere between 800 and 900.  I always thought EFI engines never dropped below 1,000 rpm.  Anybody care to speculate what's happening and if this something I need to be concerned about?

[dartman]

My 07 SE Ultra had a similar problem, IF i ran a  distance at highway speeds and  got off on an exit ramp  it would drop to about 600 rpms or stall, it would correct itself after about 20 min of normal driving , the dealer checked it repeatedly over the 2 yr period I had it but could never find a code or get it to malfunction when in their possession. I have been told that there was an ECM glitch on a number of the 07-s that could be corrected by installing an aftermarket ECM, I swapped the bike for an 09  instead.
good Luck

[Trapperdog]

My '07 did that too, or at times would idle high,13-1400. PC111 took care of it though.

[tazmun]

My '07 did that too, or at times would idle high,13-1400. PC111 took care of it though.

Sorry, but what is PC111? I have the same problem with my 06.

[Fired00d]

Sorry, but what is PC111? I have the same problem with my 06.

Dynojet Power Commander III.

 
Ride Safe,
Fired00d
 

[tazmun]

Dynojet Power Commander III.

 
Ride Safe,
Fired00d
 

Thanks! Mine has done it since new, and I have the SE race tuner pack, so I don't
know what causes it then.

[Admiral]

Anybody with SSERT or Mastertune had this problem?

[opee6969]

I had an idle problem on my 00' UC and it ended up being the idle motor. It occassionally would drop around the 600 RPM area and sometimes it would stall. Apparently there's a motor on EFI motors that controls the idle similar to a governor. Replacing the idle motor corrected the problem and it never happened again.  I'm not a motor head by any means, but that's what they told me lol.

Opee

[grc]

I had an idle problem on my 00' UC and it ended up being the idle motor. It occassionally would drop around the 600 RPM area and sometimes it would stall. Apparently there's a motor on EFI motors that controls the idle similar to a governor. Replacing the idle motor corrected the problem and it never happened again.  I'm not a motor head by any means, but that's what they told me lol.

Opee

The Delphi injection on the current models has an Idle Air Control valve which performs a similar function to the idle motor you mentioned on the Marelli injection used on the '00.  It controls idle speed by adjusting the amount of air admitted to the engine, not by moving the throttle plate but by opening a separate air passage that bypasses the throttle plate.  This is the same system used by modern automotive injection systems.  There are many reasons why this system may be erratic in controlling idle speed, but some of the possible causes are a vacuum leak, leaking or dirty fuel injectors, a Throttle Position Sensor (TPS) malfunction, or an Idle Air Control (IAC) actuator problem.  It is also possible for someone to misadjust the mechanical throttle stop, but that is rare as it requires someone to purposely drill out a plug to access the throttle stop screw.  A competent tech should be able to test the various components to determine which if any are causing the problem.

One reason I've found for erratic idle, assuming all the components check OK, has to do with the very lean mixture at idle.  Often the idle can be stabilized just by adjusting the fuel setting at idle for each cylinder.  While you might expect that a tuner would automatically do that, many do not.  That's most likely why one person had their problem corrected with a PCIII ( or SERT, etc.) while another person saw no change.  If one has the inclination to look through a collection of canned maps from Power Commander or other sources, they might notice the same thing I have.  Most maps don't seem to change the stock fuel and/or timing settings at idle.

Jerry

[Gettinold]

The Delphi injection on the current models has an Idle Air Control valve which performs a similar function to the idle motor you mentioned on the Marelli injection used on the '00.  It controls idle speed by adjusting the amount of air admitted to the engine, not by moving the throttle plate but by opening a separate air passage that bypasses the throttle plate.  This is the same system used by modern automotive injection systems.  There are many reasons why this system may be erratic in controlling idle speed, but some of the possible causes are a vacuum leak, leaking or dirty fuel injectors, a Throttle Position Sensor (TPS) malfunction, or an Idle Air Control (IAC) actuator problem.  It is also possible for someone to misadjust the mechanical throttle stop, but that is rare as it requires someone to purposely drill out a plug to access the throttle stop screw.  A competent tech should be able to test the various components to determine which if any are causing the problem.

One reason I've found for erratic idle, assuming all the components check OK, has to do with the very lean mixture at idle.  Often the idle can be stabilized just by adjusting the fuel setting at idle for each cylinder.  While you might expect that a tuner would automatically do that, many do not.  That's most likely why one person had their problem corrected with a PCIII ( or SERT, etc.) while another person saw no change.  If one has the inclination to look through a collection of canned maps from Power Commander or other sources, they might notice the same thing I have.  Most maps don't seem to change the stock fuel and/or timing settings at idle.

Jerry

Jerry
I have also been having a idle problem but mine seems like the rear cyl intermittently mis- fires. Realy idles like chit when the bike is warm and not so noticable cold. I'm leaning toward a inj problem and have a "known good set" I'm going to drop in. Normaly you would get a ck eng lite if there was a TPS or IAC. Any advice on this. ??

    Thx Dave

[highwayking]

Took the bike in to the dealer today.  Seems I had a manifold intake leak that caused the rpm drop.  They replaced the two O-rings on the cyclinder heads, so we will see if that solves it. 

[Trapperdog]

Took the bike in to the dealer today.  Seems I had a manifold intake leak that caused the rpm drop.  They replaced the two O-rings on the cyclinder heads, so we will see if that solves it. 

Hmmm...seems to me my previous bikes with intake leaks idled higher and more eractically. Either I am being sisdlexic or oem specs are so lean to begin with now that yours was trying to stall out.

[grc]

Jerry
I have also been having a idle problem but mine seems like the rear cyl intermittently mis- fires. Realy idles like chit when the bike is warm and not so noticable cold. I'm leaning toward a inj problem and have a "known good set" I'm going to drop in. Normaly you would get a ck eng lite if there was a TPS or IAC. Any advice on this. ??

    Thx Dave

Hey Dave,

You could have a dirty or leaky injector, so since you have another known good set, swapping them out is a decent idea.  It's a simple and quick job once the fuel tank is out of the way.  Worth a shot.

As for the idle being worse hot than cold, that tends to indicate a lean mixture.  When cold the ECM adds extra fuel, so it would tend to mask the issue until you get up to normal operating temp.  While that could be a dirty injector, it's more likely to be an intake air leak.  If your injector swap doesn't make any difference, check for a vacuum leak at the manifold to heads. 

Jerry

[Gettinold]

Thx Jerry. I will let you know what I find.
      Dave

[highwayking]

Took the bike in to the dealer today.  Seems I had a manifold intake leak that caused the rpm drop.  They replaced the two O-rings on the cyclinder heads, so we will see if that solves it. 

Now, I'm really frustrated.  After they replaced the intake O-rings, the bike performed well for the first two short rides.  Yesterday it was 68 and sunny so I took it for about a two hour ride.  Everything went great until I got home and slowed down to turn into my driveway.  RPMs dropped to 600.  I pulled into the garage and the rpms gradually climbed back to 1000.  So now I'm thinking my problem relates to either the outside temperature or the length of time I ride, i.e. engine heat buildup.  I really hate taking it back to the dealer again, because I'm guessing they will just trial and error this thing until I just give up in frustration.  Isn't there a code that should show up in the diagnostics as why the rpms are dropping?