stumbles, miss off idle

[tdrglide]

03 roadglide, injected, power commander, stumbles, misses just off idle. Better if I open up the throttle. No codes. Runs fine at startup when motor cold but as soon as warm the problem starts. Poor slow idle when comming to a stop. Misses on accelleration until rpms get up but not as much if I give a lot of throttle. I checked TPS. Checked for vacuum leaks. Drained and put in new fuel. I don't think it was bad fuel. Changed plugs. Plugs look fine. Could be lots of things. I'm stumped

[FLTRI]

You describe a lean situation.
Not quite enough info:
1) When did this condition start?
2) Any work done on the bike that afterward, the problem started?
3) Is the condition reliably repeatable?
Answer these and maybe we can help,
Bob

[tdrglide]

Ok
Condition started last week and has gotten worse
No work was done reciently on the bike
Yes the condition is repeatable
Start the bike up cold and runs normal for a few blocks then it starts to stumble at barely part throttle. When I say cold I mean 65 deg or so. If I let it warm up fully then it happens right off.

110", 10.4-1 cr, tman 590 cams, hpi 51mm throttle body, pcIII usb
thanks

[apendejo]

Check for pinhole leaks in the in-tank fuel lines.
AP

[kdietz]

Check for exhaust and intake leaks

[tdrglide]

Pulled the fuel pump assembly yesterday but then company showed up. Didn't see anything obvious, will take a closer look this afternoon. Might as well change the fuel filter anyways.. About the fuel pressure regulator; should I be able to blow air through it with no restriction? Because I can.
No exhaust or intake leaks

[RevJim708]

tdrglide,
What kind of plugs do you have.  If they are the ones with the screw on tops that could be your problem. I had to go back to the Champion plug with the solid top cause the screw on top would always come loose and the bike would run just like yours.
One more thing to look at
Rev Jim..............

[harleydudesam]

Try opening post "2002 RKC - trouble code P1357 « on: Today at 05:00:34 AM »

[crazybastid83]

Check for pinhole leaks in the in-tank fuel lines.
AP

I agree. With the bike running, open u the gas cap, you will hear the fuel spraying.

[Paniolo]

After checking for leaks you may want to take the Power Commander out of the loop to see if it is a contributing factor. Nothing extensive, just try the bike without it hooked up and see what happens. If the bike improves then maybe you need a tweak or adjustment. If the problem persists then it is NOT the PC and you can continue to look elsewhere,

[tdrglide]

Will check for fuel leaks but don't think thats it, but you never know. I have another pcIII but it is not a USB, it is a pcIIIr, it has a serial port so I got to go find a USB-serial port adaptor to load the map. They are cheap enough. I am also going to pull the intake manifold and check, replace seals. Wont be able to do most of this till weekend. Day job gets in the way
This bike has had some weird idle issues through several build configurations. Different heads, manifolds, maps, ect. After cruising for awhile when coming to a stop would sometimes stall or idle real low rpms for 10 to 20 seconds and the idle normal. IAC is fine and clean

[apendejo]

Again, check for leaking fuel lines inside the tank. Pull the gas cap off, listen to the inside of the tank while cycling the ignition. If you hear any hissing or gurgling sounds that is pressurized fuel. After cycling the ignition 2 or 3 times wait about 30 seconds then do it again, the fuel pump should not come on again because the system is already pressurized. If the fuel pump comes on, you have leaks.
If the leaks are minor and the fuel level is above the pinhole the pressure differential will be such that you may not notice much of a problem. It is when the holes get bigger or the fuel level isbelow the holes that you have problems with stalling, pooridle and general overall performance.
AP

[apendejo]

They look like this.

AP

[Don D]

Would suggest a compression test just to take that off the list

[tdrglide]

Fuel pump is out of the bike already, replacing filter. I will check fuel hoses carefully
Compression is fine 195+psi cold both cylinders.
Question about the fuel pressure regulator: Should I be able to blow air through the regulator unrestricted? because I can.

[04glide]

I had the same problem once and it turned out to be the engine temp sensor.

[tdrglide]

This bike has had some weird idle issues through several build configurations. Different heads, manifolds, maps, ect. After cruising for awhile when coming to a stop would sometimes stall or idle real low rpms for 10 to 20 seconds and the idle normal. IAC is fine and clean

Replaced temp sensor awhile back when chasing the low idle gremlin. No change.

Don't know if I have two different problems or one that has suddenly gotten worse.

I'll check and re-check everything I can think of

[ICANTD55]

I had a week coil do this once. It would stumble when I took off and clear when I hammered it.  See if you can borrow a coil to try.

[tdrglide]

Sorry I didn't get back to anybody on this one. But the stumble problem was really simple. There was water in the plug that connects the pcIII to the harness. Probably from washing the bike. Blew it dry, a little wd, problem gone. I should have known. I've seen it before.

The low idle when comming to a stop in cool weather issue is still there. Idles slow for 10 seconds or so then picks up to normal. Cool weather only, wierd.